Closed Landfills as Power Parks: Technical and Economic Feasibility
of Solar Energy Harvesting at Florida’s Closed Landfills
Berrin Tansel
Florida International University
Department of Civil and Environmental Engineering
Victor Londono Marin (Graduate Student)
Florida International University
Department of Civil and Environmental Engineering
Praveen Kumar Varala (Graduate Student)
Florida International University
Department of Civil and Environmental Engineering
Banu Sizirici Yildiz
Florida International University (Research Associate)
Department of Civil and Environmental Engineering
Hinkley Center for Solid and Hazardous Waste Management
University of Florida
4635 NW 53rd Avenue, Suite 205
Gainesville, FL 32653-3418
www.hinkleycenter.org
Report
FINAL REPORT
July 1, 2009 – August 31, 2010
PROJECT TITLE: Closed Landfills as Power Parks: Technical and Economic Feasibility of
Solar Energy Harvesting at Florida’s Closed Landfills
PRINCIPAL INVESTIGATOR:
Berrin Tansel, Ph.D., P.E., Florida International University, Civil and Environmental
Engineering, Associate Professor, Department, Miami, FL 33174
Ph (305) 348 2928
Fax (305) 348 2802
e-mail tanselb@fiu.edu
COMPLETION DATE: August 31, 2010
KEY WORDS: Closed landfills, solar energy harvesting, sustainable development, power parks
ABSTRACT:
Florida is one of the nation’s fastest growing states. Therefore demand for energy is growing
significantly. Florida ranks nationally among the top 5 states in the amount of energy consumed per
capita. As a result of increasingly constrained production and availability fossil fuels and
environmental concerns, renewable energy sources are gaining acceptance and are expected to play
a key role in sustainable growth and development in the coming future. For this project, suitability
of closed landfills for use as power parks was investigated. Based on the orientation, topography,
status and cover make up; two landfills were selected in south Florida (North Dade Landfill and
NW 58th street landfill). Technical and economic analyses were conducted to assess the site closure
and development needs, and design and operational factors to evaluate the suitability of closed
landfill sites for capturing solar energy. Compatibility of the closed landfill site conditions with the
structural and infrastructural needs of sustainable solar energy capture systems, optimum placement
and geographic orientation of the solar capture systems and auxiliary equipment, how much power
can be generated and the costs and benefits of using Florida’s closed landfills as power parks were
analyzed. The solar empirical model results helped to obtain the values of energy yield. At the
NW 58th street landfill the solar energy generation potential is 38.33 MW/h and the delivery of
energy could reach 20.64 MW/h. At the North-Dade Landfill, solar energy generation potential is
58.50 MW/h and the delivery energy could reach 31.37 MW/h. The Unit Cost of Energy for a
gridded PV system on a closed landfill in an urban area would be is about $ 0.100 /kW, which is
close to the average cost of energy in Florida $ 0.112 /kW. Wind load analysis on solar panels
was conducted for both landfills for wind speeds of 120-150 mph. Analysis performed on North
West 58th Street Landfill resulted in wind pressures of 58.02 lbs/sq ft and 44.17 lbs/sq ft and
wind forces corresponding to flat and south facing sloped surfaces. At the North Dade Landfill,
wind pressures were estimated as 46.40 lbs/sq ft and 38.36 lbs/sq ft for flat and south facing
sloped surfaces. The suitability assessment scores were 130.4 point for the 58th street landfill and
127.4 points for the North-Dade landfill 127.4 out of 180 total points (ideal site). This study
provides guideline to establish some criteria to implement PV system at Florida Florida’s closed
landfills to generate electricity and promote solar technology in response to growing demand for
sustainable energy sources.
Closed Landfills as Power Parks: Technical and Economic Feasibility
of Solar Energy Harvesting at Florida’s Closed Landfills
Berrin Tansel
Victor Londono Marin
Praveen Kumar Varala
Banu Sizirici Yildiz
Florida International University
Department of Civil and Environmental Engineering
ACKNOWLEDGEMENTS
The Florida State University System Hinkley Center for Solid and Hazardous Waste
Management provided financial support for this research project.
TABLE OF CONTENTS
TABLE OF CONTENTS ........................................................................................................................................... I LIST OF TABLES .................................................................................................................................................. III LIST OF FIGURES ................................................................................................................................................ IV LIST OF ACRONYMS ........................................................................................................................................... VI ABSTRACT ........................................................................................................................................................ VII EXECUTIVE SUMMARY .................................................................................................................................... VIII LIST OF KEY WORDS ......................................................................................................................................... XII Solar Thermal Technology ................................................................................................................................. xii 1. INTRODUCTION ......................................................................................................................................... 1 1.1 OBJECTIVES ................................................................................................................................................... 3 1.2 METHODOLOGY ............................................................................................................................................ 4 2. BACKGROUND........................................................................................................................................... 6 2.1 LANDFILL CHARACTERISTICS................................................................................................................... 6 2.1.1 Available Landfills ..................................................................................................................................... 6 2.1.2 Main Characteristics in Landfills .............................................................................................................. 9 2.2 SOLAR ENERGY PROFILE .......................................................................................................................... 10 2.2.1 Photovoltaic Technology .......................................................................................................................... 10 2.2.2 Solar Thermal Technology ....................................................................................................................... 10 2.2.3 Solar Energy Systems ................................................................................................................................ 11 2.2.4 Type of Solar Energy Systems Suitable for Landfills ............................................................................... 17 2.2.5 Electricity Generation and Needs for Solar Energy Systems ................................................................... 18 2.2.6 Solar Energy Case Studies ....................................................................................................................... 21 2.3 SOLAR RADIATION ON TILTED SURFACES ............................................................................................ 26 2.3.1 Solar Radiation Fundamentals .................................................................................................................. 26 2.3.2 Solar Angles ............................................................................................................................................. 27 3. METHODOLOGY ....................................................................................................................................... 31 3.1 SCREENING AND SELECTION METHODOLOGY .................................................................................... 31 3.1.1 Site Preparation ....................................................................................................................................... 31 3.1.2 Major Factors .......................................................................................................................................... 31 3.1.3 Additional Technical Factors ................................................................................................................... 35 3.2 SOLAR ENERGY GENERATION ON LADNFILLS .................................................................................... 45 3.2.1 Criteria for Screening of Solar Technology Suitability on Landfills ......................................................... 45 3.2.2 Available Solar Insolation and Sunny days/year for Florida .................................................................... 45 3.2.3 Design Approach for a Tilted Surface Model............................................................................................ 48 3.2.4 Solar Photovoltaic Power System ............................................................................................................ 56 3.2.5 Energy to Be Generated In Closed Landfills by PV System ..................................................................... 57 3.3 FOUNDATION REQUIREMENTS AND DESIGN ........................................................................................ 58 3.3.1 Factors Considered For Solar Energy Systems Placement ....................................................................... 58 3.3.2 Challenges in Using Closed Landfills For Solar Energy Generation ....................................................... 64 3.3.3 Site Preparation Needs for Panel Installation .......................................................................................... 64 3.3.4 Types of Foundations for Installing Solar Panels ..................................................................................... 65 3.3.5 Considerations for Panel Placement ......................................................................................................... 67 3.3.6 Wind Load Analyses ................................................................................................................................. 68 i
3.3.6.2. WIND LOAD ANALYSES FOR CASE STUDY LANDFILLS ............................................................................. 70 WIND LOAD ANALYSES FOR THE CASE STUDY LANDFILLS ARE PROVIDED IN APPENDIX C.TECHNCIAL, ECONOMICAL, ENVIRONMENTAL AND SOCIAL ASSESMENT ............................................................................... 70 TECHNCIAL, ECONOMICAL, ENVIRONMENTAL AND SOCIAL ASSESMENT ............................................................ 71 4.1 TECHNICAL ASSESSMENT ......................................................................................................................... 71 4.1.1 Cap Improvement and Maintenance ......................................................................................................... 71 4.1.2 Grid Distance ............................................................................................................................................ 72 4.1.3 Compatibility ............................................................................................................................................. 72 4.1.4 Control of Leachate and Gas ................................................................................................................... 73 4.1.5 Site Maintenance ................................................................................................................................. 73 4.1.6 Surface Water Control ............................................................................................................................. 73 4.1.7 Infrastructure Needs ................................................................................................................................. 73 4.1.8 Layout and Arrangement .......................................................................................................................... 74 4.1.9 Rated Capacity ......................................................................................................................................... 74 4.2 ECONOMICAL ASSESSMENT ..................................................................................................................... 74 4.2.1 Energy Delivery Factor ............................................................................................................................. 75 4.2.2 Initial Capital Cost ................................................................................................................................... 75 4.2.3 Availability and Maintenance .................................................................................................................. 76 4.2.4 Energy Cost Estimates ............................................................................................................................. 76 4.2.5 Sensitivity Analysis ................................................................................................................................... 77 4.2.6 Profitability Index .................................................................................................................................... 77 4.2.7 Fund for Post Closure Care ..................................................................................................................... 77 4.3 ENVIRONMENTAL SUITABILITY ANALYSIS ......................................................................................... 77 4.3.1 Reduction of Greenhouse Emissions ........................................................................................................ 77 4.3.2 Environmental Sustainability ................................................................................................................... 78 4.3.3 Visual Impacts .......................................................................................................................................... 80 4.3.4 Index of Renewable Energy for Power Production .................................................................................. 80 4.4 SOCIAL ASSESSMENT ................................................................................................................................. 80 4.5 TECHNICAL, ECONOMICAL, ENVIRONMENTAL, AND SOCIAL ASSESSMENT SUMMARY ...................................... 80 4.5 FUTURE DESIGN CONSIDERATION FOR LANDFILL ............................................................................. 83 4.6 COST AND BENEFITS OF USING FLORIDA’S CLOSED LANDFILLS AS POWER PARKS .................. 84 4.6.1 Cost of Solar Panels ................................................................................................................................. 84 4.6.2 Dimensions ............................................................................................................................................... 84 4.6.3 Weight ....................................................................................................................................................... 84 5. CONCLUSIONS ............................................................................................................................................... 87 6. REFERENCES .................................................................................................................................................. 89 7. APPENDICES .................................................................................................................................................. 94 ii
LIST OF TABLES
Table 1. Inventory of solid waste facilities in Florida .................................................................... 7 Table 2. Class I Landfills in Miami-Dade area ............................................................................... 8 Table 3. Class II Landfills in Miami-Dade area ............................................................................. 8 Table 4. Class III Landfill in Miami-Dade area .............................................................................. 8 Table 5. Differences between Fixed tilt and Tracking Systems ................................................... 13 Table 6. Screening of landfillts to implement PV systems in Florida .......................................... 33 Table 7. 58th Street Landfill optimum placement configuration .................................................. 35 Table 8. North Dade Landfill optimum placement configuration ................................................ 36 Table 9. The specific locations of the landfill sites ...................................................................... 37 Table 10. Typical landfill gas composition................................................................................... 44 Table 11. Screening solar technology suitability on landfills ....................................................... 46 Table 12. Solar insulation values for various locations in Florida ............................................... 46 Table 13. Averagely available clear (sunny days), partly cloudy and cloudy days in a year ....... 47 Table 14. Possible average sunshine percentages for certain locations in Florida ....................... 47 Table 15. Data header ................................................................................................................... 51 Table 16. Data fields ..................................................................................................................... 51 Table 17. Station selected in TMY3 data records provided by NSRDB ...................................... 52 Table 18. Standard energy Yield for a place within the Miami Dade area. .................................. 57 Table 19. Shading angle calculation for panels in winter season ................................................. 62 Table 20. Complications and solutions to the solar panels installation ........................................ 65 Table 21. Grid distance criteria valuation ..................................................................................... 72 Table 22. Upfront cost for a PV system in the next 10 years ....................................................... 76 Table 23. Existing renewable energy installations ....................................................................... 79 Table 24. Projected renewable energy installations ..................................................................... 79 Table 25. Suitability assessment for photovoltaic implementation in closed landfills ................. 81 Table 26. Solar panel dimensions ................................................................................................. 84 Table 27. Solar power system costs .............................................................................................. 86 iii
LIST OF FIGURES
Figure 1. Average residential electricity price in 2007.......................................................................1 Figure 2. Change in average cost PV cells ......................................................................................2 Figure 3. Isocost curves of solar insolation .....................................................................................2 Figure 4. General outline of project methodology ...........................................................................4 Figure 5. Utilization of solar energy to generate electricity ..........................................................11 Figure 6. Fixed tilt system schematic. ...........................................................................................11 Figure 7. Single axis tracking system schematic ...........................................................................12 Figure 8. Double axis tracking system schematic ..........................................................................13 Figure 9. Examples of solar thermal technology ...........................................................................14 Figure 10. Schematic diagram of Fresnel lens ...............................................................................15 Figure 11. Parabolic collectors: a) Mechanism b) Schematic........................................................16 Figure 12. Schematic diagram of parabolic collector ....................................................................16 Figure 13. Schematic layout of power tower system. ....................................................................17 Figure 14. Formation of p-n junction ............................................................................................18 Figure 15. Movement of electrons and holes in a solar cell resulting in Electricity (DC) ............19 Figure 16. Flow chart explaining the conversion of DC to AC .....................................................19 Figure17. Typical diagram of solar thermal system ......................................................................20 Figure 18. Pennsauken Landfill solar project ................................................................................22 Figure 19. Solar panels installation diagram..................................................................................22 Figure 20. Final view of the site ....................................................................................................22 Figure 21. Flexible panels installation diagram at the Tessman Road Landfill Site .....................23 Figure 24: Solar panels installation at Holmes Road Landfill site ................................................25 Figure 25. Technical feasibility of solar energy harvesting ..........................................................26 Figure 26. Angle of incidence in a tilted surface ...........................................................................28 Figure 27. Azimuth angles .............................................................................................................28 Figure 28. Zenith angle ..................................................................................................................29 Figure 29. Solar declination angles during the year ......................................................................29 Figure 30. Hour angle ....................................................................................................................30 Figure 31. 58th Landfill Satellite view ..........................................................................................35 Figure 32. North-Dade landfill satellite view ................................................................................36 Figure 33. View of 58th Street Landfill .........................................................................................37 Figure 34. View of North-Dade Landfill .......................................................................................38 Figure 35. Cover profile proposed to develop a PV landfill project ..............................................39 Figure 36. Basic components for a stand-alone solar system ........................................................39 Figure 37. Major components of a photovoltaic power system ....................................................40 Figure 38. Typical landfill water collection system.......................................................................41 Figure 39. A simplified cover layer to control runoff in the PV system for a landfill site ..........42 Figure 40. Cover system ................................................................................................................42 Figure 41. A proposed cover layer system for a Landfill site with PV system .............................42 Figure 42. Typical current fluctuation in the 58th landfill.............................................................44 Figure 43. Radiation on a flat plate surface at different angles .....................................................53 Figure 45. Winter maximum sun elevation at a 20° tilted surface.................................................54 Figure 44. Solar altitude .................................................................................................................54 iv
Figure 46. Winter maximum sun elevation at a 50° tilted surface.................................................55 Figure 47. Summer maximum sun elevation at a 20° tilted surface ..............................................55 Figure 48. Summer maximum sun elevation at a 50° tilted surface ..............................................55 Figure 49. Stand-alone PV or line extension cost ..........................................................................57 Figure 50. Energy yield and orientation ........................................................................................58 Figure 51. Placement of solar panels on horizontal and sloped surfaces on landfill. ....................58 Figure 52. Wind speed chart for Florida (3-second-peak-gust method) ........................................59 Figure 53. Effect of wind loads on solar systems based on wind direction ...................................60 Figure 54. Wind effects on solar panels with ballasted frame foundation.....................................66 Figure 55. Wind effects on solar panels with concrete slab foundation. .......................................66 Figure 56. Wind effects on solar panels with pre-cast concrete footings. .....................................66 Figure 57. Landfill settlement over time........................................................................................67 Figure 58. Solar module retail price index.....................................................................................75 Figure 59. US primary energy consumption by source and sector 2008. .....................................78 Figure 60. Cover set up for panel installation ................................................................................83 Figure 61. Price of panels per KW.................................................................................................86 v
LIST OF ACRONYMS
USEPA
MSW
FPL
PV
FDEP
GIS
NRDB
NSRDB
TMY
AC
DC
United States Environmental Protection Agency
Municipal Solid Waste
Florida Power& Light
Photovoltaic
Florida Department of Environmental Protection
Geographic Information System
National Radiation Data Base
National Solar Radiation Data Base
typical meteorological year
Alternating Current
Direct Current
vi
ABSTRACT
Florida is one of the nation’s fastest growing states; therefore, demand for energy is growing
significantly. Florida ranks nationally among the top 5 states in the amount of energy consumed per
capita. As a result of increasingly constrained production and availability of fossil fuels and
environmental concerns, renewable energy sources are gaining acceptance and are expected to play
a key role in sustainable growth and development. The solar energy capture systems are becoming
economically feasible at locations with low land values. Lands which are used for solar capture are
called power parks. For this project, suitability of closed landfills for use as power parks was
investigated. Based on the orientation, topography, operational status and cover/cap design, two
landfills were selected in south Florida (North Dade Landfill and 58th street landfill) for in-depth
assessment. Technical and economic analyses were conducted to evaluate the site closure and
development needs, and design and operational factors to assess the suitability of the closed landfill
sites for solar energy harvesting. Compatibility of the closed landfill site conditions with the
structural and infrastructural needs of sustainable solar energy capture systems, optimum placement
and geographic orientation of the solar capture systems and auxiliary equipment, energy yiled,
costs and benefits of using Florida’s closed landfills as power parks were analyzed.
The empirical models for solar energy yield were used to estimate the energy yield. In
the 58th street landfill, the solar energy potential was estimated at 38.33 MW/h and the delivery
of energy could reach 20.64 MW/h. In the North-Dade landfill, the solar energy potential was
estimated at 58.50 MW/h and the corresponding delivery energy would be 31.37 MW/h. The
feasibility of energy harvesting from closed landfills in Florida was determined by the upfront
cost of the technology and energy yield efficiency. Based on the analysis carried out, the unit
cost of energy for a gridded PV system (no batteries) on a closed landfill in an urban area would
be about $ 0.100 /kW, which is close to the actual average cost of energy in Florida $ 0.112 /kW
(EIA 2007). Wind load analysis on solar panels was evaluated at both landfills. Analysis were
performed for wind speeds 120-150 mph. The analysis performed on both flat and south facing
sloped surfaces of North Dade Landfill resulted in wind pressures of 46.40 lbs/sq ft and 38.36
lbs/sq ft, respectively. The wind forces corresponding to effective area of panels resulted in
wind pressures of 58.02 lbs/sq ft and 44 17 lbs/sq ft for flat and south facing sloped surfaces,
respectively. The overall suitability assessment scores were 130.4 point for the 58th street landfill
and 127.4 points for the North-Dade landfill 127.4 out of 180 total points (ideal site).
This study provides preliminary guideline to establish design criteria to implement PV
system on closed landfills in Florida to generate sustainable electricity. Development of closed
landfills as power parks would be a feasible passive use option in Florida while making the
closed landfills to be functional for sustainable energy harvesting.
vii
EXECUTIVE SUMMARY
1. INTRODUCTION
Florida is one of the nation’s fastest growing states. With about 1,000 new residents every
day, overall demand for energy is growing significantly, increasing stress on the energy delivery
infrastructure. Even with substantial lifestyle changes, conservation and energy efficiency
improvements; global energy demand is likely to more than triple within the next fifty years. The
solar energy capture systems are becoming economically feasible for use at several national and
international power parks. For this project, suitability of closed landfills for use as power parks
(partially and totally) was investigated. Technical and economic analyses were conducted to assess
the site closure and development needs, as well as design and operational factors to evaluate the
suitability of closed landfills for capturing solar energy. Compatibility of the closed landfill site
conditions with the structural and infrastructural needs of sustainable solar energy capture systems,
optimum placementand geographic orientation of the solar capture systems, auxiliary equipment
needs, and sustainability of the land use as power parks were evaluated. This project was
responsive to two of the research priorities listed in the 2009-10 Research Agenda (No. 7 and No.
12) of the Hinkley Center for Solid and Hazardous Waste Management.
2. OBJECTIVES
The objectives of this project are;
•
•
•
•
•
•
Evaluate the feasibility of using Florida’s closed landfills as power parks to capture
solar energy. Evaluate suitability of Florida’s landfills for installation of solar
energy capture units;
Analyze site conditions and energy yield;
Conduct feasibility analysis from technical, economic, and environmental
perspectives;
Evaluate site conditions and maintenance requirements for sustainable energy
generation.
Estimate how much power can be generated if closed landfills are used as solar
power parks in Florida?
Analyze the costs and benefits of using Florida’s closed landfills as power parks.
3. METHODOLOGY
During this research project, suitability of closed landfills for use as power parks (partially
and totally) was investigated. Technical and economic analyses were conducted to assess the site
closure and development needs, and design and operational factors to evaluate the suitability of
closed landfill sites for capturing solar energy. Compatibility of the closed landfill site conditions
with the structural and infrastructural needs of sustainable solar energy capture systems, optimum
viii
placement and geographic orientation of the solar capture systems, auxiliary equipment needs, and
sustainability of the end use as for renewable energy generation were evaluated.
4. CONCLUSIONS
Comprehensive analyses were conducted to evaluate the suitability closed landfill sites
for use as power parks in the State of Florida. Wind loads, site slope, panel weight, foundation
design considerations, landfill settlement, control of leachate and gas, shading effects,
economical, environmental, and social aspects were considered for effective installation of solar
energy harvesting systems on closed landfills sites. For the suitability analyses, technical and
economic factors such as suitability of efficient solar energy harvesting systems based on landfill
characteristics, selection of suitable landfill area for maximum solar energy capture, availability
of nearest utility grid system, preparation of suitable landfill cap to support foundations (if
needed), landfill cap maintenance and vegetation, panel maintenance, structural and
infrastructural needs, auxiliary equipment and structures, public awareness and acceptance were
also considered.
A total of 18 criteria were identified and evaluated for the suitability analysis. These
included 10 technical criteria, 4 economical criteria, 3 environmental criteria, and 1 social
criterion. For each of the criterion, intrinsic values were evaluated and surrogate values were
assigned out of 180 total points in deciding suitability of the site for solar energy harvesting.
Due to the large amount of sites in the State of Florida, selected technical criteria were
identified for screening the sites. The screening criteria included site orientation, topography,
status (closed or active), and cover. Based on the preliminary screening, two landfills in the
southeast Florida were selected to conduct detailed analysis. The detailed analyses were
conducted to evaluate technical, economical, environmental, and social factors. Site visits and
topographic assessment were performed to evaluate the technical conditions at each site.
Furthermore, solar radiation values were estimated to obtain energy yield and solar energy
harvesting potential at each site.
The overall suitability assessment scores were 130.4 point for the 58th street landfill and
127.4 points for the North-Dade landfill 127.4 out of 180 total points (ideal site). There is some
margin of error in the evaluations of the sites due to variations in the interpretation of site
properties. One reason for the North-Dade landfill’s lower score was that North-Dade landfill is
currently active; hence it received lower scores for some of the technical criteria.
The analysis by the solar empirical model provided the energy yield estimates at each
site. At the 58th street landfill, there exists a solar energy potential to generate 38.33 MW/h and
the energy delivery could be as much as 20.64 MW/h. At the North-Dade landfill, the solar
energy potential is 58.50 MW/h and the delivery energy potential could be as high as 31.37
MW/h. Based on the Florida Governor’s Energy Office, solar energy potential for Florida in the
year 2020 is 156,000 GWh and currently the installed capacity is about 2,900 MWh. Based on
the findings, there is a significant potential for solar energy harvesting in Florida. The results of
ix
this study provide a preliminary guidance for the utilization of closed landfills as power parks for
sustainable energy generation.
Use of closed landfills for solar energy harvesting in Florida was also evaluated for the
upfront costs needed for the solar technology and energy yield efficiency. The unit cost of energy
for a gridded PV system (no batteries) on a closed landfill in an urban area was estimated at
about 0.100 $/kW. This value is close to the actual average cost of energy in Florida (based on
the Energy Information Administration 2007 report, average cost of electricity is 0.112 $/kW).
The gridded solar energy is could be a good competitor in the near future for fossil fuel
technologies. Event tough these prices indicate that solar harvesting systems could get into the
energy market, there are other concerns in terms of reliability and load equalization if the energy
is sold to the users directly.
An empirical model was developed based on the information provided by the Solar
Radiation Data of USA. The historical solar radiation data were statistically compressed to show
the average energy that can be produced at a specific location at different tilt angles of the solar
panels. Energy efficiency factor is critical in determining if the PV technology will penetrate into
the energy market effectively in the near future. Solar panels could provide up to 220 W/h (based
on the testing of the panels at each site site) per panel for a flat panel. The efficiency is expected
to increase, making the technology more affordable in the near future. The average solar
radiation availability for the south orientation in the North-Dade landfill was estimated at 396.29
W/m2 by the empirical model. This indicates that PV technology is providing at half the energy
that could be obtained. Hence, the solar empirical model had to be corrected so that it would not
over predict the energy yield at each site.
Based on the literature research and empirical model results, the appropriate surface
angle for photovoltaic systems is between 10 and 40 degrees facing south. Hence, slopes
between 0.2 m/m and 0.8 m/m are the preferable range for the PV systems to work efficiently. If
this slope is compared with typical slopes on landfills (i.e., 0.33 m/m), it could be concluded that
the closed landfills are within the range of maximum efficiency. Because of the wide range of
slope and the small changes in the energy yield with slope; it is reasonable to consider a PV
system which does not include a support or a structure to generate tilted angles; rathet will be
placed directly on the ground supports. Furthermore, the tilted panels placed on the top of the
site (i.e., flat zones) could have slightly higher energy yields.
Wind load analysis on solar panels for North Dade Landfill and North West 58th Street
Landfill were conducted as case studies. The design wind speeds for Miami Dade County is
between 140-150 mph, with the average design wind speed of 146 mph (FBC, 2008). Analyses
were performed for wind speeds of 120-150 mph. Evergreen solar panels of ES-A-200 were used
for analysis and Analytical Procedure from Chapter 6: Wind Loads of ASCE 7-05 was used as
the methodology to evaluate the wind loads (Minimum Design Loads for Building and Other
Structures). At the North Dade Landfill For panels placed on flat and south facing sloped
surfaces, the estimated wind pressures were 46.40 lbs/sq ft and 38.36 lbs/sq ft, respectively. At
the North West 58th Street Landfill, the estimated wind pressures were 58.02 lbs/sq ft and 44.17
lbs/sq ft and wind forces corresponding to panels placed on flat and south facing sloped surfaces.
Florida being a hurricane-prone region, there is possibility of higher wind loads. Hence, wind
x
loads should also be considered with appropriate supporting structures and safety factors. Wind
tunnel experiments can provide necessary design data for solar installations for design purposes.
This study provides preliminary guideline to establish technical, economic,
environmental and social criteria to implement PV system in Florida’s closed landfills.
Developing closed landfills as power parks to generate renewable energy will promote
sustainable development efforts.
5. RESULTS
A comprehensive analysis was conducted to evaluate the suitability of closed landfills to
be developed as power parks in Florida. The suitability analysis included technical, economical,
environmental, and social criteria. Based on the orientation, topography, status, and cover
design; two landfills in the South-East of Florida (North Dade Landfill and NW 58th street
landfill) were selected as case study landfills to conduct in-depth analyses.
An empirical model was used to estimate the energy yield. At the 58th street landfill,
there exists a solar energy potential to generate about 38.33 MW/h and the delivery of energy
could reach 20.64 MW/h. At the North-Dade landfill, the solar energy potential is about 58.50
MW/h and the delivery energy could be 31.37 MW/h. The unit cost of energy for a gridded PV
system (no batteries) on a closed landfill in an urban area was estimated at about $0.100 /kW,
which is close to the actual average cost of energy in Florida which was $0.112 /kW in 2007
(EIA 2007).
Wind load analysis on solar panels were performed for wind speeds of 120-150 mph.
Based on the analysis performed on both flat and south facing sloped surfaces of North Dade
Landfill, wind pressures were 46.40 lbs/sq ft and 38.36 lbs/sq ft, respectively. Analysis
performed for the North West 58th Street Landfill resulted in wind pressures of 58.02 lbs/sq ft
and 44.17 lbs/sq ft for flat and south facing sloped surfaces, respectively.
This study provides preliminary guideline to establish design criteria to implement PV
system on closed landfills in Florida to generate sustainable electricity. Development of closed
landfills as power parks would be a feasible passive use alternative in Florida while making the
closed landfills functional for harvesting of sustainable energy.
xi
LIST OF KEY WORDS
Closed Landfill
Solar Energy
Power Parks
Photovoltaic cells
Solar Panels
Solar Radiation
Tilt angle
Solar Thermal Technology Dish/Engine systems
Power Tower Systems
Foundation
Brownfields
xii
1. INTRODUCTION
The average residential retail price of electricity in the United States was 10.64 cents per
KW-h in 2007 which shows a 4.7% increase per year since 2002. The average price of electricity in
the US is expected to increase to 15.93 cents per KW-hr by 2015. Florida ranks nationally among
the top 5 states in the amount of energy consumed per capita. In 2007, the average price of
electricity in Florida was 11.20 cents which is above the national average as shown in Figure 1
(EIA, 2007). Even with substantial lifestyle changes, conservation, and energy efficiency
improvements, global energy demand is likely to more than triple within next fifty years.
Figure 1. Average residential electricity price in 2007 (Energy Information Administration, 2008).
As a result of increasingly regulated production of fossil fuels and environmental concerns,
renewable energy sources are gaining acceptance and are expected to play a key role in sustainable
growth and development initiatives in the coming decades. A comparison of the estimated energy
costs from nonrenewable and renewable resources are provided below (PNM Speakers Bureau,
2009):
• Coal
$ 0.03 - $ 0.04 /kW-h
• Hydro
$ 0.02 - $ 0.03 /kW-h
• Wind
$ 0.04 - $ 0.06 /kW-h
• Biomass
$ 0.08 - $ 0.11/kW-h
• Geothermal $ 0.05 - $ 0.12 /kW-h
• Central Solar $ 0.12 - $ 0.18 /kW-h
• Photovoltaic $ 0.20 - $ 0.30 /kW-h
Currently, only rural and customers far away from the power grid use solar panels because it
is more cost effective than extending power lines to remote locations. The two main types of
systems that are used for harnessing solar energy include:
1
1. Solar collectors with mirrored surfaces that reflect sunlight to heat up liquid to generate
electricity, and
2. Photovoltaics that use photovoltaic cells that absorb direct sunlight.
Technological advancements are slowly making it economical for photovoltaic manufacturing
industry as well as solar collector devices as presented in Figure 2. Commercial and utility scale
PV systems are currently economically competitive with grid electricity prices in many areas,
especially regions with insolation levels as shown in Figure 3.
Figure 2. Change in average cost PV cells (NREL, 2006)
Figure 3. Isocost curves of solar insolation (Adapted from Bradford, 2006)
Although solar energy is free, harnessing solar energy requires investment. Some factors to
be considered in selection of solar harvesting systems include (Miggins, 2008):
1. Type of solar harvesting system to be used for specific application (i.e., mono, poly,
amorphous, ribbon, concentrated, silicon or copper based);
2
2.
3.
4.
5.
6.
7.
Solar density ( watts per square foot);
Efficiency (conversion of light to energy);
Durability (ability to withstand environmental factors);
Physical properties, heat tolerance, mounting, wiring, grounding, spacing requirements;
Appearance, form and function, and dual use deployment;
Manufacturer and availability, warranty, maintenance requirements and useful life.
Closed landfill sites generally are developed as open areas and public parks, while some
sites have been developed for active uses such as sports complexes and shopping malls (Tansel,
1998). Recently, a number of closed landfills have been considered as potential sites for renewable
energy generation (i.e., capturing energy from wind or sun). The largest solar power site in the
Army is now constructed on a closed landfill to supply power to Fort Carson, Colorado
(Galentine, 2008). The city of Houston was recently awarded $50,000 from the U.S. EPA to
develop a solar energy plant on a closed landfill to revitalize the 300-acre site near downtown
(Barry and Tillman, 2008). Florida Power & Light (FPL) is planning to build a solar energy project
about half the size of a football field on a Sarasota County landfill, fulfilling a promise to customers
(Mayk, 2006). About 23,000 customers have agreed to pay an additional $9.75 per month to
help FPL buy more power generated by wind, solar and bio-energy generators. The New Jersey
Meadowlands Commission (NJMC) is also planning to generate approximately 5 megawatts of
energy from of solar harvesting on a landfill, to produce renewable energy and encourage
businesses to take advantage of the state’s growing green economy (Aberback, 2008). Progress
Energy signed a contract to buy power from a solar power plant to be built on a closed landfill in
Haywood County, North Carolina (CleanTech, 2008). The Tessman Road Landfill in San
Antonio, Texas is being capped with flexible solar energy capturing cover consisting of more
than 1,000 strips with photovoltaic silicon cells (Herrera, 2009). The 5.6 acre landfill is expected
to generate nine megawatts of electricity. SunPower Corporation, a manufacturer of highefficiency solar systems, has been working with the Korean energy company EnE System to
build a 2-megawatt solar energy power plant on a landfill in the City of Jeonju, Korea (Kwon,
2008). The solar energy covers can provide benefits not only for inspection and maintenance but
also more effective for odor control and storm water management.
1.1 OBJECTIVES
This project evaluated the feasibility of using closed landfills as power parks to capture solar
energy in Florida. The critical factors that must be considered when planning a final site use for
closed landfills include settlement, foundation characteristics, control of leachate and gas,
vegetation, and final grade. If a closed landfill site is planned to be used as a power park for
capturing solar energy, additional technical and economic factors should be evaluated. These
factors include direction and orientation of the landfill area to be used for installation of solar
capture systems, types of solar harvesting systems suitable for use at landfill sites, geographical
location and orientation of the landfill site, topographical characteristics, structural and
infrastructural needs, site maintenance, type and integrity of the cap system, auxiliary structures
needed, economic factors, and public acceptance.
The specific objectives of the project are to:
3
1.
2.
3.
4.
Evaluate suitability of Florida’s landfills for installation of solar energy capture
units;
Analyze site conditions and energy yield;
Conduct feasibility analysis from technical, economic, and environmental
perspectives;
Evaluate site conditions and maintenance requirements for sustainable energy
generation.
1.2 METHODOLOGY
During this project, suitability of closed landfills for use as power parks (partial or entire
area) was investigated. Technical and economic analyses were conducted to assess the site closure
and development needs, as well as design and operational factors to evaluate the suitability of closed
landfill sites for capturing solar energy. Compatibility of site conditions at closed landfills with the
structural and infrastructural needs of solar energy capture systems, optimum placement and
geographic orientation of the solar capture systems, auxiliary equipment needs, and sustainability of
the end use as a power park were evaluated. Figure 4 presents the general outline of the
methodology.
Figure 4. General outline of project methodology
The project was conducted according to the following work plan:
Task I. Preliminary assessment of suitability of Florida’s closed landfills for harnessing solar
energy.
4
This task involved:
1. Development of technical, environmental, and economic criteria to evaluate feasibility of
location and orientation of solar energy capture systems on landfill sites;
2. Development of a short list of potential landfills sites in Florida;
3. Identification of at least 3 landfill sites as case studies for development as power parks.
Task II. Analysis of technical factors.
The task involved:
1. Identification and assessment of key design and operational factors for sustainability of
using closed landfill sites as power parks;
2. Compatibility of site conditions with structural and infrastructural needs for use as a
power parks;
3. Site closure measures to make closed landfill sites suitable for use as power parks;
4. Types of solar energy capture and storage systems appropriate for landfills;
5. Site utilization measures for determining areas suitable for installation of solar energy
capture systems to optimize projected energy yield.
Task III. Assessment of environmental factors.
This task evaluated the projected impacts on carbon footprint, energy generation potential, and
environmental sustainability. In addition, other environmental factors such as climate factors
(e.g., solar insolation, rain events), geographic location, orientation of landfill areas, and
proximity to urban areas will be evaluated.
Task IV. Economic assessment (in-depth).
The economic analyses included a detailed assessment of factors which could impact feasibility
and sustainability of solar power parks on closed landfill sites. The factors will include:
•
•
•
•
•
•
Site improvement and maintenance costs;
Capital costs;
Operating and maintenance costs;
Net energy yield;
Net energy cost;
Net savings.
Task V. Analysis of long term and short term benefits.
This task evaluated the data collected in Tasks II and III in view of the potential environmental
risks in the context of end use and post-closure care needs.
Task VI. Cost-benefit analysis.
A detailed cost-benefit analysis was developed using both quantitative and qualitative analyses.
The outcome of the this report will be a guidance document for developing closed landfill sites
as power parks for harvesting solar energy.
5
2. BACKGROUND
In the recent years, with the increasing interest in renewable energy sources, closed
landfills are being identified as potential areas for solar energy generation, both in the USA and
elsewhere. Pennsauken landfill in Pennsylvania, Tessman Landfill in San Antonio, Texas, and
Georgia Landfill in Atlanta are examples of landfills developed for solar energy harvesting. In
Florida, the Sarasota Project is generating 250 kW-h on the closed Bee Ridge landfill. Cloased
landfills could be used for installation of PV systems for energy generation.
2.1 LANDFILL CHARACTERISTICS
The landfill inventory provided by the Florida Department of Environmental Protection
(FDEP) landfills locator was investigated to determine site availability and identification of
suitable landfills in Florida (Hunn et al., 1987). The available sites were screened based on size,
type of fille, and location were evaluated and screened.
2.1.1 Available Landfills
Using the data available through the FDEP, each landfill was evaluated based on the
landfill class and the class status. Table 1 presents the summary of the solid waste facilities in
Florida as provided by the FDEP inventory data.
FDEP also provided GIS tools which are called “Landfills Locator” (Hunn et al., 1987).
This tool allows identification of the location of each site at the regional scale. According to the
FDEP, there are about 3700 disposal sites around the Florida. There are 126 secure landfills
(Hazardous wastes, class III) and 42 of them are closed, there are 161 monofills (designated
wastes, class II) 18 of them are closed, and there are 225 sanitary landfills (municipal solid
wastes, class I) 123 of them are closed. Also there are classifications within these three main
types of disposal sites. For this research, 183 sites, which were closed were evaluated. Tables 2,
3 and 4 present the status of the facilities located in the Miami Dade County.
6
Asbestos Disposal Facility
Ash Monofil
Auto/White Goods Shredder
Biohazardous Waste Stor.
Biohazardous Waste Treat.
Biomass Gas/Liquid Prod.
C & D Debris, Unauthorized
Class I Landfill
Class Ii Landfill
Class Iii Landfill
Composting Plant
C & D Debris Recycling
C & D Debris
Disaster Debris Staging Area
Incineration Only
Incineration
Lack Of Data
Land Clearing Debris
Manure Composting
Material Recovery
Old Dump
Other Composting W/Di
Other Composting W/Re
Other Disposal Facility
Other Treatment
Other Volume Reduction
Shreder/Pulverizer
Sludge Composting
Sludge Concentration
Sludge Disposal Facility
Soil Treatment
Special Waste
Tire Disposal
Transfer Station
Treatment Facility
Unauthorized Disposal
Unauthorized Dump
Use Oil Collection
Use Oil Recycling
Volume Red./Transfer Stat.
Waste Tire Collection
Waste Tire Site, Una Uth
Waste To Energy
Yard Trash Composting
Yard Trash Comp./w Recycle
Yard Trash Processing
Total
1
5
1
1
2
4
3
1
2
49
2
42
7
19
105
7
1
12
1
1
123
18
42
1
2
155
33
1
9
1
2
12
9
1
6
136
3
38
8
1
8
4
23
4
1
1
1
1
3
1
4
5
2
1
2
3
2
4
2
4
2
2
3
3
15
1
9
1
3
4
1
2
13
1
6
2
8
2
18
118
1
17
18
6
1
2
1
1
1
10
1
34
1
1
6
2
4
26
6
2
661
3
4
8
1
142
1
2
29
4
2
2
5
1
1
2
1
1
8
11
2
4
3
2
1
1
4
2
1
2
31
1
5
24
7
1
3
1
1
401
3
1
296
9
3
3
2
6
268
10
1
35
93
1
2
3
23
3
375
830
56
740
Total
Proposed
2
41
7
1
15
2
38
4
3
4
1
4
1
2
Not Yet Determined
Nfa,No Further
Action/Inactive
Never Operated,
Permit Never Used
Inactive
4
3
4
15
5
17
10
2
74
1
1
1
6
10
6
8
2
624
1
3
6
6
15
9
1
1
1
89
1
65
1
5
3
5
110
1
5
Closed, With GW
Monitoring
Closed, No GW
Monitoring
Cleanup, Waste
Removed
CLASS
Cerclis Preliminary
Assessment
Activity Not
Permitted
STATUS
Active
Table 1. Inventory of solid waste facilities in Florida (FDEP inventory data)
1
7
4
2
9
6
12
225
161
126
37
30
409
681
4
19
20
124
6
105
357
1
10
45
13
4
9
9
4
49
6
9
6
197
2
19
10
1
17
6
68
8
18
35
18
434
Table 2. Class I Landfills in Miami-Dade area (Solid Waste Facility Inventory Report 2009)
Facility ID
Facility Name
County
56819
58th St Landfill
Miami-Dade
56820
South Dade Dump
Miami-Dade
56824
Miami-Dade
Miami-Dade
Inactive
57135
South Dade Landfill
South Dade Solid Waste Reduct.
Facility
City of North Miami Beach Ojus
Landfill
Munisport-North Miami Landfill
Facility Status
Closed, with GW
Monitoring
Closed, with GW
Monitoring
Active
57136
Town Of Surfside Dump
Miami-Dade
57870
Tony Waher Dump
Medley Landfill And Recycling
Center (See 60080)
Medley Landfill And Recycling
Center
Miami-Dade
Closed, with GW
Monitoring
Inactive
Closed, with GW
Monitoring
Inactive
Miami-Dade
Inactive
Miami-Dade
Active
56831
57134
60079
60080
Miami-Dade
Miami-Dade
Table 3. Class II Landfills in Miami-Dade area (Solid Waste Facility Inventory Report 2009)
Facility ID
Facility Name
County
56817
K-Land
Miami-Dade
56818
Haulover Bch Park Dump
Miami-Dade
56829
Trail Glade Ranges
Miami-Dade
56980
Homestead-Florida City Dump
Miami-Dade
60082
Minton's Landfill
Miami-Dade
60083
Pace Dump
Miami-Dade
Facility Status
Closed, with GW
Monitoring
Closed, with GW
Monitoring
Closed, with GW
Monitoring
Closed, with GW
Monitoring
Inactive
Closed, with GW
Monitoring
Table 4. Class III Landfill in Miami-Dade area (Solid Waste Facility Inventory Report 2009)
Facility ID
56822
Facility Name
North Dade Landfill
County
Miami-Dade
57137
Virginia Key Rubbish Dump
Miami-Dade
60081
Marks Brothers Co Trash Dump
Miami-Dade
8
Facility Status
Active
Closed, with GW
Monitoring
Closed, with GW
Monitoring
2.1.2 Main Characteristics in Landfills Development of a landfill involves technical elements for safe disposal of solid waste that
cannot be recycled, reduced, or eliminated. One of the main design objectives of the landfill is to
prevent the pollution of the environment and protect the human health during the operation and
after the closure of the landfill. For this project PV system were considered for use of closed
landfill sites without damaging the existing infrastructure at the site. Therefore, characteristics of
a landfill that are compatible with the PV systems were analyzed. These characteristics include
the site area, topography, location, post closure plan, cap system, and runoff. A brief description
of each factors is provided below.
2.1.2.1 Area
Closed sites are more suitable to be developed as power parks. It is also important for a
large fraction of the area to have suitable orientation (i.e., south facing). Size and orientation of
the available area determine suitability of the overall landfill site.
2.1.2.2 Topography
Evenness and symmetry in the landfill shape are important factors for solar power
harvesting system layout. Shape of the landfill may affect the wind load and the panel layout
configuration. It is necessary to optimize the use of the topography in relation to wind load and
panel layout for improved performance. Landfill sites are developed based on a specific
geometry conceived during the design phase. The design and development of a site can be
configured based on the degree of compatibility of the finished site topography with solar energy
harvesting potential.
2.1.2.3 Urban and Rural Location
Urban sites are closer to the power grid and the distribution system; hence the losses
during distribution are relatively small. Rural areas with high customer potential could be
considered for solar systems. However, PV systems can provide a sustainable alternative to
supplement th increasing demands in urban areas.
2.1.2.4 Post Closure Plan Implementation
This project evaluated the post closure use of well maintained landfill sites. It is
necessary to reevaluate the implementation of the post closure care plan and maintenance needs
at the candidate sites for installation of the PV system for compatibility of the existing
infrastructure with the installation and maintenance requirements of the PV system.
2.1.2.5 Geographical Orientation
Site slopes and orientation are important due to the sun path during the day and the
sun/earth rotation during the year. The angles at which the surfaces receive the sun light are
critical for the efficiency of the PV system. Sites with larger areas facing south, flat areas, and
9
slopes range between 0.2 m/m and 0.4 m/m are more suitable for installation of solar harvesting
systems.
2.1.2.6 Cap System
In the solar energy interaction with the PV system, it was seen that photovoltaic systems
follow the most efficient angle by which the sun rays strike the solar panel. This angle is called
the angle of incidence. A good angle of incidence produces more energy. For this reason, solar
panels need to be tilted for the best range of the solar incidence. The tilted panels need to be
mounted on foundation systems which are able to withstand the wind loads while being
compatible with the stability of the cap.
2.1.2.7 Runoff Collection
Runoff managements in landfills is achieved by infiltration of water through the
vegetative support, and then soil layer where the water is conveyed to surface water ditches and
ponds. Placement of the solar panels on the landfill may affect the runoff quantity and patterns.
Control and maintenance of the vegetative cover need to be evaluate so that suitable vegetative
cover which require less maintenance can be utilized to minimize site access.
2.2 SOLAR ENERGY PROFILE
Solar energy is the freely available renewable resource of the nature. Utilization of solar
energy to generate electricity involves the photovoltaic technology and solar thermal technology
(http://www.epa.gov/RDEE/energy-and-you/affect/non-hydro.html#solar).
2.2.1 Photovoltaic Technology
The photovoltaic technology utilizes solar panels which are made of solar cells
constructed with semi-conducting materials such as silicon. When light hits the panel, a
chemical reaction (i.e., photovoltaic effect) takes place resulting in electricity generation. The
generated electricity is then collected through proper wiring systems and then supplied as shown
in Figure 5.a (http://www.epa.gov/RDEE/energy-and-you/affect/non-hydro.html#solar).
2.2.2 Solar Thermal Technology
The solar thermal technology involves the collection of light energy through mirrors or
concentrators to heat a liquid to create steam, which is then used to turn a generator and create
electricity as shown in Figure 5.b (http://www.epa.gov/RDEE/energy-and-you/affect/nonhydro.html#solar).
10
a) Solar thermal technology
b) Photovoltaic technology
Figure 5. Utilization of solar energy to generate electricity
2.2.3 Solar Energy Systems
2.2.3.1 Photovoltaic Systems
Photovoltaic systems can be fixed tilt type or tracking type laid. Each requires a suitable
foundation depending on the panel weight, wind load, and other environmental factors. Different
mounting structures available for PV systems are discussed below.
2.2.3.1.1 Fixed Tilt Type: These systems consist of solar panels attached on the mounting
structure in such a way that the panels are installed at a fixed angle with respect to the horizontal
axis, generally equal to the latitude of the site in order to achieve maximum annual solar
radiation as shown in Figure 6 (Sampson, 2009).
Figure 6. Fixed tilt system schematic
11
Tilt angle adjustments: For better performance in winter, tilt angle can be adjusted to
(http://unirac.com/faq/faqs-design3.php):
tilt angle= (latitude+15)
For better performance in summer, tilt angle can be adjusted to:
tilt angle= (latitude-15)
Advantages: Requires less land space to avoid shading effects between panels (Sampson, 2009).
Disadvantages: Lower output compared to the Tracking Systems (Sampson, 2009).
2.2.3.1.2 Tracking Axis Type: These systems consist of solar panels fixed on the mounting
structure such that the tilt angle of the panels is adjusted with respect to the sun’s position by a
tracking system. The tracking system is placed on the horizontal axis (i.e., the panels follow the
sun’s path). These systems are operate at a higher efficiency compared to fixed tilt type.
Single axis tracking systems: These systems follow the sun’s path from east to west direction
with respect to the horizontal axis as shown in Figure 7 (Sampson, 2009).
Figure 7. Single axis tracking system schematic
Double axis tracking systems: These systems follow the sun’s path along east to west and north
to south directions and are capable of catching the sun rays at any point of time and are not
affected by the time of day or season. Double axis tracking systems require larger land space to
avoid shading between the panels, have higher operation and maintenance costs, require energy
to run the tracking systems at two axes as shown in Figure 8 (Sampson, 2009).
12
Figure 8. Double axis tracking system schematic
Advantages
1) Higher output compared to the fixed tilt systems (Sampson, 2009).
2) Capable of higher output in winter seasons when the sun is low in the horizon (Sampson,
2009).
Disadvantages
1) Require large space to avoid shading effects (Sampson, 2009).
2) High operation and maintenance costs, require energy to run motors for operating the tracking
systems (Sampson, 2009).
3) May be affected by the settlement of the landfill, disturbing the panel’s position towards the
sun and resulting in lower output (Sampson, 2009).
Differences between fixed tilt and tracking systems are summarized in Table 5.
Table 5. Differences between Fixed tilt and Tracking Systems (Sampson, 2009)
Single Axis tracking
system
Double axis tracking
system
Fixed with respect to site’s
latitude.
Winter= (Latitude+15)
Summer=(Latitude-15)
Adjusted with respect to
to the sun’s position in
east to west direction.
Adjusted with respect to
to Sun’s position in any
direction
Output
Least efficient
More compared to fixed
tilt angle systems.
Highest. Can produce high
energy yield in winter
months when the sun is
low in the horizon
Example
Pennsauken Landfill Solar
Nellis Air force base,
Project, Pennsauken New Jersey Nevada
Type
Tilt
angle
Fixed Tilt angle
13
--
2.2.3.2 Solar Thermal Systems
Solar thermal systems are also called as concentrating solar power systems. A low
temperature solar thermal system (<100oC) involves low concentration of sunlight and is
generally used for heating or hot water preparation in homes and other industrial applications.
High temperature solar thermal systems (>100oC) use various mirror configurations for
concentrating the sunlight and converting the energy into high temperature heat and then to
steam. Steam is used to generate electricity by using the turbine-generator or to run the chemical
reactions. The electricity production with this technology is cheaper when used with large grid
applications (http://www.solarthermalworld.org/node/1187). There are three types of solar
thermal systems generally used for electricity generation: (1) Linear concentrator systems, (2)
Dish/Engine systems, and (3) Power tower systems. Figure 9 presents the solar thermal systems
used for power generation.
Figure 9. Examples of solar thermal technology
2.2.3.2.1 Linear Concentrator Systems
The Fresnel Lens: These lenses are semi-transparent, generally made of plastic. They have
been in use since 1822. They are able to generate steam when used with thermal energy
absorbers and fluid. They have the focal point close to the lens plate and their efficiency depends
on the number of groves present on the lens as shown in Figure 10 (http://www.five-shades-ofgreen-energy.com/solar_collectors.html#pts).
14
Figure 10. Schematic diagram of Fresnel lens
Advantages: The advantages of Fresnel lens system include low manufacturing cost, low space
requirements and ability to concentrate the solar energy into PV cells (http://www.five-shadesof-green-energy.com/solar_collectors.html#pts).
Disadvantages: Fresnel lens systems can be harmful when handled carelessly causing severe
injuries due to their high efficiency (http://www.five-shades-of-greenenergy.com/solar_collectors.html#pts).
Parabolic trough type collectors: Parabolic trough type collectors have U-shaped or parabolic
troughs to concentrate the solar energy onto a receiver tube filled with working fluid (e.g., water)
as presented in Figure 11.a. The receiver tube is placed along the focal line as shown in Figure
11.b and transparent glass tubes can be used to cover the receiver tubes to reduce the heat loss.
The troughs may be of single-axis, dual-axis or stationary. These troughs are capable of focusing
up to 100 times the sun’s normal intensity and can produce liquid temperatures up to 800˚F
inside the receiver tube, where the heated fluid can be used to produce electricity (i.e., using
steam turbines) (http://www.five-shades-of-greenenergy.com/solar_collectors.html#pts,http://www.daviddarling.info/encyclopedia/P/AE_paraboli
c_trough_collector.html).
Advantages: The troughs are generally used in running steam turbines for electricity generation.
Disadvantages: Requires large land area.
15
(a)
(b)
Figure 11. Parabolic collectors: a) Mechanism, b) Schematic
2.2.3.2.2 Dish/Engine systems
Parabolic dish type collectors: These collectors use mirror type reflectors with the absorber
located at the focal point as shown in Figure 12. These systems generally use dual axis tracking
system to follow the sun. The receiver located at the focal point collects the solar energy which
can heat approximately up to 1000˚C. Heat engines are connected to the receiver and can be used
for electricity generation
(http://www.daviddarling.info/encyclopedia/P/AE_parabolic_trough_collector.html).
Figure 12. Schematic diagram of parabolic collector
Advantages: The main advantage of parabolic dish type collectors is that they can be used to
achieve high efficiencies in converting solar energy to electricity in small power capacity ranges
(http://www.daviddarling.info/encyclopedia/P/AE_parabolic_trough_collector.html).
16
Disadvantages: These systems are suitable for smaller scale power production (i.e., between 325 kilowatts) (Sampson, 2009).
2.2.3.2.3 Power Tower Systems
Power tower systems consist of central receiver located on the top of the tower which is
also called as the central receiver solar power plant. The sunlight reaching the mirrors located
downside is reflected back to the receiver located at the top as shown in Figure13. Computers are
used in positioning the large field of mirrors, so that the reflected sunlight is always focused on
to the receiver located on the tower. As a result, temperatures above 1000˚C are obtained at the
receiver producing high temperature steam for electricity generation.
(http://www.daviddarling.info/encyclopedia/P/AE_parabolic_trough_collector.html).
Figure 13. Schematic layout of power tower system
Advantages: The temperatures can be reached above 1000˚C and high pressure steam is
generated to produce electricity.
Disadvantages: Requires large land area.
2.2.4 Type of Solar Energy Systems Suitable for Landfills
Generally, power tower and linear concentrating solar power systems demand or require
large areas for optimal operational capacity. Hence, they are best suited for large scale
production plants with a capacity of at least 50 megawatts. Also large scale power production
capability is required to optimize linear concentrator and power tower solar systems. Installation
on landfill sites may not be feasible and hence due to foundation requirements. Future research
on economics and efficiency may allow design options for using concentrating solar power
systems on closed landfills as a feasible option. Among the available concentrating solar power
systems, dish/engine systems can be used on landfills for smaller scale production. Currently, PV
solar systems have been the most commonly used solar energy harvesting systems, implemented
and tested on landfills (Sampson, 2009)
17
2.2.5 Electricity Generation and Needs for Solar Energy Systems
2.2.5.1 Electricity Generation
Electricity generation from solar energy comes under the category of non-hydroelectric
renewable energy sources such as wind, biomass, landfill gas, and geothermal and is a
sustainable resource for generating electricity (http://www.epa.gov/RDEE/energy-andyou/affect/non-hydro.html#solar).
2.2.5.1.1 Photovoltaic Electricity
Majority of the commercial solar cells are made from thin layer of silicon, which is doped
on one side with positive type dopant (i.e., boron as electron acceptor impurity) and the other
side with negative type dopant (i.e., phosphorus or arsenic as electron donor impurity) to create a
p-n junction (depletion layer) between the two layers as shown in Figure 14. The n-type
semiconductor is capable of donating electrons and the p-type semiconductor functions as
electron acceptor (http://www.solarpower2day.net/solar-cells/).
Figure 14. Formation of p-n junction
Generation electricity in a solar cell takes place according to the following steps as depicted
in Figure 15 (http://www.solarpower2day.net/solarcells/):
1) The sunlight falling on the solar cell (frequency dependent) excites the electrons of the
semi-conductor material with the help of energy carrying particles (i.e., photons)
resulting in the release of electrons (-ve charge);
2) Electrons leaving the parent atom, creating holes (+ve charge);
3) The charge carriers moving across the junction (i.e., electrons towards p-side and holes
towards n-side) resulting in diffusion process;
4) The electric field produced forces the electrons to the far n-type side of the material and
holes to the far p-type side resulting in a small (typically ~0.5V) difference in electric
potential (voltage) between the two sides, which can be collected by connecting the two
sides with conductive wire.
18
Figure 15. Movement of electrons and holes in a solar cell resulting in electricity (DC)
After the generation of direct current from the photovoltaic panels, the usage of
electricity involves the conversion process of direct current (DC) to alternating current (AC) as
follows and as depicted in Figure 16:
1) Direct current generated from the panels is collected and transferred to the controllers.
2) Batteries are used for energy storage.
3) Direct current is sent to the inverters, where the direct current is converted alternating
current.
4) The alternating current is connected to the utility grid system and supplied to customers.
Figure 16. Flow chart explaining the conversion of DC to AC
19
2.2.5.1.2 Solar Thermal Electricity
Solar thermal electricity consists of utilization of solar collectors (mirrors, reflective
devices, concentrators) to capture and concentrate the energy provided by sunlight.
Concentration of solar radiation using concentrators for electricity generation and power
transmission to homes or offices is accomplished as following, as depicted in Figure 17
(http://www.nexteraenergyresources.com/content/where/portfolio/solar/solar_plant.shtm).
1) Sunlight falling on the collectors is concentrated by the receiver and heats up the
synthetic oil, which heats up the water to create steam.
2) The steam passes through pipes to a turbine-generator which produces electricity.
3) The steam is condensed and reused. The entire cyclic process repeats again.
4) From the turbine-generator, the electricity passes through the transformers increasing the
voltage, to be transmitted over long distances.
5) On cloudy days or at lower levels of sunlight, a supplementary natural gas boiler at the
plant can be used to burn natural gas to heat the water, producing steam to generate
electricity.
Figure17. Typical diagram of solar thermal system (adapted from
http://www.nexteraenergyresources.com/content/where/portfolio/solar/solar_plant.shtml)
20
2.2.6 Solar Energy Case Studies
2.2.6.1 Pennsauken Landfill Solar Project
Site Name: Pennsauken Landfill.
Site Location: Pennsauken, New Jersey.
Landfill Type: Municipal Solid Waste Landfill.
Site Description: The Pennsauken Sanitary Landfill is a municipal solid waste landfill located in
Pennsauken, New Jersey. It is owned and operated by the Pollution Control Financing Authority
of Camden County (PCFACC). Landfill is still open with majority of waste being bulky and
construction and demolition waste. The landfill consists of three distinct cells, namely A-Site, DSite, and E-Site. The A-Site was operated from 1960-1982. It was capped in 2003-2004 and
about contains 2.3 million metric tons of solid waste covering 39 acres with PV panel installation
(2006-2008) covering about 10 acres (of total 39 acres). The D-Site was operated from 19811990 and E-site has been active since 1990 with expected closure date of 2019.
The solar panel installation was done by Pennsylvania Power and Light Renewable Energy
(PPLRE). Panels were placed on the areas which were landfilled from 1960 through 1990. First
panels were placed about 16 years after landfilling ceased in these areas. The future site use
plans include use of thin film solar cells which will requires about 6-7 acres/MW.
Solar System Description:
• Panels Used: Crystalline Photovoltaic
• Mounting Systems (Top surfaces): Ballast Systems
• Mounting Systems (Side slopes) : Pre-cast concrete footings
Solar energy systems were installed at both A-Site and D-Site with A-Site consisting of PV
panels installed on the side slopes and top area, while the D-Site system consist of PV panels
installed only on the top area. Panels lose about 0.6% efficiency each year. The general layouts
of solar panels on landfill area are shown in Figures 19 and 20.
Tilt angle: Tilt angle is equal to the latitude of the site for the panels located on the top of the
landfill. The panels were placed facing towards south-west instead of due south as shown in
Figure 18a. The panels placed on the slopes are generally placed at the same angle and in slope
direction with panels facing south-west direction as shown in Figure 18b.
Solar Energy Capacity: 2.1 MW capacity with 0.5 MW on site-A (top area), 1.6 MW on site-D
(top area) and site-A (slope area). Panels were installed during 2006-2008.
Electricity Generation: During 2008, 2605 MW of electricity was produced. During 2009, 2,156
MW was generated through October 31st. Monthly output in 2009 ranged from 141 MW in
January to 276 MW in July. The monthly output in 2008 ranged from 111 MW in Dec to 305
MW in June (Messics, 2010; 2009; Sampson, 2009)
21
a) On flat surfaces
b) On sloped surfaces
Figure 18. Pennsauken Landfill Solar Project (http://www.mass.gov/dep/energy/pennsauk.pdf)
Figure 19. Solar Panels Installation diagram
Figure 20. Final view of the site
(http://www.mass.gov/dep/energy/pennsauk.pdf)
2.2.6.2 Tessman Road Landfill, San Antonio, Texas
Site Name: Tessman Road Landfill
Site Location: San Antonio, Texas
Landfill Type: Municipal Solid Waste Landfill
Site Description: The site is a municipal solid waste landfill located in San Antonio, Texas,
owned and operated by Republic Services, Inc. The site was capable of receiving waste
quantities between 2500-5000 tons/day.
Innovative geo-membrane cover, also known as Solar Energy Cover (SEC) was used to cover the
site (5.6 acres) with 18 degree south facing slope in 2008. The geo-membrane cover serves as
landfill cap as well as mounting surface for placement of flexible photovoltaic panels. Use of
solar energy cover differs from the RCRA Subtitle D cover system. The top cover does not
include the geo-membrane drainage layer, vegetative support layer, and top soil layer which are
required by the Texas Commission of Environmental Quality.
The solar energy cover is capable of:
22
•
•
•
•
Reducing infiltration;
Protection of soil from wind and erosion;
Protection of cap from puncturing damages due to hail stones;
Protection of cap from damages due to sunlight exposure and temperatures variations.
Based on the above benefits, the geo-membrane cover was approved to be used as a conventional
landfill cover. The flexible panel installation diagram is provided in Figure 21. Engineering
design services were provided by HDR Engineering Inc. The energy cover consisted of 60
millimeter polypropylene based material (thermoplastic polyolefin) with appropriate
reinforcement. Flexible, laminate type photovoltaic solar collection strips (≈ ¼ inches) were
directly attached to the geo-membrane cover. Construction for the project commenced in
December 2008 and was completed in April 2009. Figure 23 provides the final view of the
Tessman Road Landfill site.
Solar System Description: 1050 Flexible, laminate type PV solar collection strips (≈ ¼ inch
thick) were placed on south facing side slope by directly attaching them to the geo-membrane
cover as shown in Figure 22. Flexible panels were Uni-Solar PVL-128 model with the following
characteristics with power rating between 128 W-144W.
Tilt angle: PV strips on the slopes were placed at the same angle and in slope direction of the
landfill surface (i.e., south facing at 18˚).
Solar Energy Capacity: 182 megawatt hours.
Electricity Generation: Estimated electricity output from the solar array of 135KW system is
182,319 kilowatt-hours (approx.).Combined with landfill gas energy, 9 megawatts of electricity
can be generated capable of powering 5500 homes.
Benefits: 0.089$/kWh resulting in energy revenue of 16000$/year (Young, 2009; Solar Cap
Project, 2008; Sampson, 2009).
Figure 21. Flexible panel installation diagram of at the Tessman Road Landfill site
(Young, 2009)
23
Figure 22. Flexible panel placement at
Tessman Road Landfill site (Young, 2009)
Figure 23. Final view of the Tessman
Road Landfill site (Young, 2009)
2.2.6.3 Holmes Road Landfill, Houston
Site Name: Holmes Road Landfill
Site Location: Houston, Texas.
Landfill Type: Municipal Solid Waste Landfill.
Site Description: The 300-acre landfill site is located in Houston, Texas. The landfill was filled
with brush, construction and demolition debris, household waste, industrial waste, tires, and
scrap. It has been closed since mid-1970’s and was covered with trees and vegetation which
required clearing and grading before the installation of the solar energy system.
SRA International, Inc., provided technical and economic analyses of the proposed solar plant
construction on the closed landfill site which was under Brownfield’s sustainability pilot
community of US EPA’s Brownfields program. The goal of the sustainability pilot was to
provide technical assistance to support communities/regions in achieving greener, more
sustainable site development for cleanup and redevelopment at brownfield sites. US EPA’s
assistance through SRA International Inc., was used for analysis of engineering and
environmental issues linked with solar farm installation. Tetra Tech Inc. was chosen as a subcontractor under SRA to perform regulatory assessment for the project. Limited Environmental
Site Investigation (ESI) was conducted by Terracon in September 2006 and later City of Houston
(owner of the property) conducted the necessary environmental site investigations. The study
was performed by SRA International Inc., with the help of city of Houston personnel, US EPA
staff, subcontractor Tetra Tech Inc.
Southern half of the landfill, covering 150 acres was selected for solar farm construction to
produce 10 MW. Amorphous silicon panels (2.2 m x2.6 m) used were capable of producing 1
MW per 15 acres with appropriate spacing between the panel rows to avoid shading effects.
Minimum of 4ft soil cover was recommended with mounting structures reaching 3ft deep,
supported by poured concrete footings and installation of racks.
Use of closed municipal solid waste landfills is regulated under Title 30 of Texas Administrative
Code (TAC) Chapter 330, Subchapter T which specifies the necessary rules and regulations to be
24
followed by persons owning, leasing or developing the property over closed municipal solid
waste landfills.
Solar System Description: As the site was heavily covered with vegetation, clearing and
grading were required. Sire preparation resulted in increase in engineering costs and project
time. At least four feet soil cover was required to support the installation of the solar systems.
Uniform cap depth was preferred for strong foundation. Soil from areas of thick with soil depth
was moved to areas with shallow depth. In addition, some soil was imported to ensure sufficient
soil depth. Poured concrete footing foundations were recommended instead of slab foundations.
For solar energy harvesting, thin film PV solar panels were chosen over crystalline panels.
Following recommendations proposed by SRA International Inc., for the solar energy system
were design with the following specifications:
•
•
•
•
Fixed tilt single axis mounting structures(tilt angle= 30 degrees)
Poured concrete footings (instead of slab footings);
Amorphous thin film solar PV panels (conversion efficiency range= 6-7.5%)
500-kilowatt inverters.
Tilt angle: Amorphous silicon solar panels were installed at fixed tilt angle of 30 degrees for
maximum annual energy production as shown in Figure 24.
Solar Energy Capacity: 10 MW
Electricity Generation: As per SRA analysis, peak output for 10 MW DC could generate
12,526,260 kWh per year considering derating factor of 79% for losses. The 10 MW solar plant
could produce about 326,000,000 kWh considering the panel output degradation rate of 1% per
year over project life of 30 years (SRA Int., 2008; Sampson, 2010) .
Figure 24. Solar Panels Installation at Holmes Road Landfill site
(http://www.epa.gov/brownfields/sustain_plts/factsheets/houston_solar.pdf)
25
2.3 SOLAR RADIATION ON TILTED SURFACES
The section presents analyses for:
1. Identifying suitable conditions for design and development of landfills for solar
energy harvesting;
2. Assessing suitability of closed landfills for use as power parks; and
3. Estimation of energy yield from photovoltaic systems placed on closed landfills.
The important parameters for analyses (i.e., solar radiation, landfill slope, technology)
were identified as presented in Figure 25. The important variables included solar radiation
captured in a flat surface (both at a tilted or at a flat angle), suitable landfill surface t
configurations, and energy production from specific radiation data sets (depending on the
geographic location). The parameters evaluated in technical and economic analyses are discussed
below.
Figure 25. Technical feasibility of solar energy harvesting
2.3.1 Solar Radiation Fundamentals
This section provides a discussion on absorption of solar radiation to produce energy by a
flat plate in relation to its orientation and the geographic location.
26
2.3.1.1 The Solar Constant
The solar constant is defined as “the intensity of solar radiation, between 0.3 and 5 μm
wavelength beyond the earth’s atmosphere.” The average amount of solar radiation that strikes
the earth’s surface is about 435.5 Btu/h-ft2 (1373 W/m2) (Duffie and Beckam 1980). The average
radiation is varies with geographic location and during the year due to earth’s rotation and
position in relation to the Sun.
2.3.1.2 Solar Radiation and the Earth’s Movements
The earth orbits around the Sun on an elliptical path. Hence, depending on the earth’s
orbital position; the seasons change, changing the average solar radiation received at a specific
location. For example, in the Northern hemisphere, in the winter when the earth’s surface is
closer to the Sun, the solar radiation reaches an average maximum value of 1416 W/m2, and
when it is summer it is about 1325 W/m2 (Thacher, 2005). This is counterintuitive due to the
elliptical nature of the orbit and the tilt of the earth’s axis. The earth’s axle is tilted 23.45
degrees (to the plane of its orbit) which is called the declination angle (δ). This angle is produced
in all the latitudes of the earth. For example in the equator line it changes from +23.45° on June
21 to -23.45° on December 21. Hence, for each year the earth’s tilt varies by 46.9 degrees.
2.3.1.3 Tilted Plate Irradiance
The amount of solar energy that is striking on a tilted plate surface is known as
irradiance. Because of the position of the earth changes during the day and also by earth’s
position on its orbit; the sun’s angle changes with time. The angles that are used to estimate the
irradiance surfaces are defined below:
•
•
•
•
•
•
•
•
•
Angle of incidence
Latitude
Longitude
Surface tilt angle
Azimuth angle
Surface solar azimuth, zenith angle
Declination angle
Solar altitude
Hour angle
θ
La
Lo
β
φ
θZ
δ
ε
ω
2.3.2 Solar Angles
The energy that comes from the sun is carried through the space by sunlight. When the
sunlight reached earth, solar radiation warms the planet. The rate at which this radiation is
absorbed by the surface varies with the position of the surface, orientation, angle of incidence,
and seasons. The angles that are used to estimate the irradiance are discussed below.
27
2.3.2.1 Incident angle θ (Theta)
Incident angle is the angle between the direct solar beam and the line normal to the
surface plate as shown in Figure 26. For solar time (ω), when the latitude and the orientation of
the plate are known, the angle of incidence can be calculated from (Thacher, 2005):
cosθ = sinδ sinLa cosβ - sinδ cosLa sinβ cosγ + cosδ cosLa cosβ cosω
+ cosδ sinLa sinβ cosγ cosω + cosδ sinβ sinγ sinω
(1)
In the case the plate is horizontal β=0, and θ=θZ and the equation is simplified to:
cosθZ = sinδ sinLa + cosδ cosLa cosω
(2)
2.3.2.2 Surface Tilt Angle β (Beta)
Surface tilt angle is the angle between the horizontal and the surface plate as shown in Figure 26.
Solar beam
Normal
θ
ε
South
β
North
Figure 26. Angle of incidence in a tilted surface
2.3.2.3 Azimuth Angle φ
Azimuth angle is the angle between the position of the sun measured east or west of the
true south; it is equal to zero at solar noon as shown in Figure 27. At other times of the day, the
following equation developed by Solar Energy Research Institute (SERI) can be used.
cosφ
= (sinε sinLa - sinδ)/(cosε cosLa)
(3)
South
Solar beam
φ
East
West
Figure 27. Azimuth angles
28
2.3.2.4 Surface Solar Azimuth or Zenith Angle (θZ)
Surface solar azimuth or zenith angle is the angle between projections onto a horizontal
plane of a line to the sun and the normal to the irradiated surface as shown in Figure 28.
Normal
Solar beam
θZ
South
North
Figure 28. Zenith angle
2.3.2.5 Declination angle δ (Delta)
Declination angle is the angle between the earth-sun line at solar noon and the earth’s
equatorial plane. Figure 29 presents the changes in the solar declination through the year.
2.3.2.6 Solar altitude ε (Epsilon)
Solar altitude is the angle between the horizontal plane and the direct solar beam. It is
estimated at noon by the equation as following.
ε = 90 – Latitude + declination
(4)
At other times of the day:
sinε = cosL cosδcosH+ sinLasinδ
(5)
Figure 29. Solar declination angles during the year
29
2.3.2.7 Hour angle ω (Omega)
Hour angle is the product of the earth’s angular rate of movement. For each hour it has a value
of 15 degrees, positive in the morning and negative in the afternoon. For example, H=15 degrees
at 11:00 in the morning, and -15 degrees at 01:00 in the afternoon, at noon is zero, is known as
the apparent solar time (AST) as shown in Figure 30. The equation is provided by SERI can be
used to calculate AST as follows:
AST = Local standard time +
equation time x (4 minutes (local meridian – local longitude))
Normal
ω = -15° at 1:00 pm
ω = 15° at 11:00 am
West
East
Figure 30. Hour angle
30
(6)
3. METHODOLOGY
3.1 SCREENING AND SELECTION METHODOLOGY
This section discusses site characteristics that affect suitability of a closed landfill for
solar energy capture by photovoltaic systems.
3.1.1 Site Preparation
The technical parameters were evaluated using a normalized weighted parameter scale.
The site characteristics important for PV systems were evaluated from the technical, economical,
social, environmental aspects. There are 1000 closed landfills located in Florida. For selection of
the case study landfills, two sites were selected in consultation with Miami Dade Solid Waste
Department and screening criteria was applied to estimate possible energy yield.
3.1.2 Major Factors
Major factors include selected technical criteria which define the minimum suitability
criteria for screening purposes. These factors include area, topography, location, geographic
orientation, cap system and status (i.e., active or closed). The major factors were scaled from 0
(least suitable) to 10 most suitable) for solar harvesting.
3.1.2.1 Area
The highest value in the area is defined as 10 ( best value) on a scale of 0 to 10. Other
values are scaled from this one. The weight factor of the area in the overall scale is 40%.
3.1.2.2 Topography and Symmetry
The topography is defined as the evenness of the site. Some sites have vegetation which
makes it difficult to inspect the topography. In general sites with grass cover and good
symmetry assigned a value of 10, sites with trees and bushes are valued at 4. The sites that do not
show any symmetry (i.e., abandoned sites with no monitoring) are valued between 1 and 4. The
weight factor of topography in the overall scale is 15%.
3.1.2.3 Urban and Rural Location
Sites located in urban areas are more suitable for the project than the rural areas due to
the close proximity of the costumers. The values were assigned as 5 for sites close to rural and
10 for sites close to urban area. The weight factor of in the overall scale is 20%.
3.1.2.4 Geographic Orientation
The sites that are facing south are better suited for solar radiation absorption. The sites
with most areas facing south are good candidates. Landfills with north to south orientation were
31
valued at 5 and those with east to west orientation were valued at 10. The weight factor of
geographic orientation in the overall scale is 10%.
3.1.2.5 Cap System
Cap system is in general 2 feet deep, the cover layer is made up by grass, soil,
geomembrane, drainage, and geotextile, as most sites use to implement. In further analysis, sites
chosen as a result of the screening process will be assessed in the cap configuration and
characteristics under different scenarios, in general solar panel at a flat and tilted angle. This
landfill is valuated as 10% on the whole landfill characteristics. As a result of the superficial
valuation of the sites in this characteristic a value of 5 is assigned per site. The weight of cap
system in overall scaling is 10%.
3.1.2.6 Status
Closed landfills are more suitable for the PV systems. Therefore, closed landfills were
valued at 10 and active landfills were valued at 5. The weight factor of the landfill status in the
overall scale is 10%.
32
Table 6. Screening of landfills to implement PV systems in Florida
Cap System (6)
Area (Acres)(1)
Urban /Rural (2)
Geog. Orientation (3)
Active-/Closed (4)
Topography (5)
Cap System (6)
30% (1)
20% (2)
10% ( 3)
15% (4)
15% (5)
10% (6)
310
Ur
N-S
Cl
4
5
10.0
10
5
10
4
5
3
2
0.5
1.5
0.6
0.5
8
155
Ru
N-S
Cl
8
5
5.0
5
5
10
8
5
1.5
1
0.5
1.5
1.2
0.5
6
40
Ru
N-S
Ac
8
5
1.3
5
5
5
8
5
0.4
1
0.5
0.8
1.2
0.5
4
0
Ur
__
__
0
0
0.0
0
0
0
0
0
0
0
0
0
0
0
0
48
Ur
__
__
4
5
1.5
8
5
10
4
5
0.5
1.6
0.5
1.5
0.6
0.5
5
139
Ur
N-S
In
3
5
4.5
10
5
10
3
5
1.3
2
0.5
1.5
0.5
0.5
6
177
Ur
N-S
Cl
4
5
5.7
10
5
10
4
5
1.7
2
0.5
1.5
0.6
0.5
7
0
0
0.4
0
0
0
0
0
0.1
0
0
0
0
0
0
11.1
0
Active-/Closed (4)
Total *
Area (Acres)(1)
Topography (5)
58th St LF (Main
County Landfill)
South Dade
Dump
South Dade
Landfill
South Dade Sw
Reduct Facility
(Facility)
City Of North
Miami Beach Ojus
Landfill (Park)
Munisport-North
Miami Landfill
Town Of Surfside
Dump
Tony Waher
Dump Facility
Medley Landfill
And Recycling
Center
Medley Landfill
And Recycling
Center
Weight Per Factor
Geog. Orientation (3)
Class I
Site
Criteria Valuation Values
Urban /Rural (2)
Characteristics Inputs
0
0
111
Ur
E-W
4
5
3.6
10
10
8
4
5
1.1
2
1
1.2
0.6
0.5
6
12
Ur
E-W
8
5
0.4
10
10
5
8
5
0.1
2
1
0.8
1.2
0.5
6
33
Urban /Rural (2)
Geog. Orientation (3)
Active-/Closed (4)
Topography (5)
Cap System (6)
30% (1)
20% (2)
10% ( 3)
15% (4)
15% (5)
10% (6)
0
0
0.0
0.0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
N-S
4
5
1.4
5
5
10
4
5
0.4
1
0.5
1.5
0.6
0.5
5
Ur
E-W
4
5
1.8
10
10
10
4
5
0.5
2
1
1.5
0.6
0.5
6
0
Ur
__
__
0
0
0.0
0
0
0
0
0
0
0
0
0
0
0
0
0
Ur
__
__
0
0
0.0
0
0
0
0
0
0
0
0
0
0
0
0
150
88.9
Ur
Ru
E-W
E-W
Ac
Cl
10
1
5
5
4.8
2.9
10
5
10
10
5
10
10
1
5
5
1.5
0.9
2
1
1
1
0.8
1.5
1.5
0.2
0.5
0.5
7
5
0
Ur
N/A
Cl
0
0
0.0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Ur
Ur
__
__
44
Ru
55.1
Area (Acres)(1)
0
0
Urban /Rural (2)
__
__
Area (Acres)(1)
Cap System (6)
Weight Per Factor
Topography (5)
K-Land (Park)
Haulover Bch
Park Dump (Golf
Club)
Trail Glade
Ranges
HomesteadFlorida City Dump
Minton's Landfill
(Junk car)
Pace Dump
(Shopping)
North Dade LF
Virginia Key
Rubbish Dump
Marks Brothers
Co Trash Dump
(Dolphin Mall)
Criteria Valuation Values
Active-/Closed (4)
Class III
Calss II
Site
Geog. Orientation (3)
Characteristics Inputs
*From 0 (worst) to 10 (best) for suitability for solar harvesting
34
Total *
3.1.3 Additional Technical Factors
Additional factors were used for detailed analysis of the screened sites to assess
implementation of the solar harvesting systems on the landfill. The sites with the highest
total values from the screening process were 58th street Landfill, North Dade LF, and
Town of Surfside Dump shown in Table 6. All these sites have good characteristics; large
area, good topography, and located in urban areas. Based on site inspections; 58th Street
Landfill and North Dade Landfill were selected for the further analysis for suitability for
PV systems.
3.1.3.1 Optimum Placement
The 58th street landfill the topography and optimum placement areas for the PV
systems are presented in Figure 31 and Table 7.
Figure 31. 58th Landfill satellite view (Miami Dade County Department of Solid Waste
Management. Annual landfill surveys. Not scaled. 2009-2010)
Table 7. 58th Street Landfill optimum placement configuration
Cell number
Sheet 5
Sheet 7
Sheet 8
Sheet 9
Sheet 6
Sheet 4
Placement area (ha)
(0.25x21)
(0.65x21)
(0.7x21)
(0.25x21)
wetland
Debris zone
35
Area available (ha)
5.25
13.65
14.7
5.25
-
The North Dade landfill topography and optimum placement areas for the PV systems are
presented in Figure 32 and Table 8.
Figure 32. North-Dade landfill satellite view (Miami Dade County Department of Solid
Waste Management. Annual landfill surveys. 2009-2010)
Table 8. North Dade Landfill optimum placement configuration
Cell number
Placement area (ha)
Area available (ha)
Sheet 2
(0.75x15)
11.25
Sheet 3
(0.75x15)
11.25
Sheet 4
(0.25x15)
1.25
Sheet 5
(0.2x15)
3.0
Sheet 6
Active
Sheet 7
Active
3.1.3.2 Geographical Location
Geographical orientation and location are important factors since solar energy
depends on the longitude and latitude of the site. Sites closer to the equator receive more
solar energy during the year. The specific locations of the landfill sites are given in Table
9.
36
Table 9. The specific locations of the landfill sites
Name
Latitude
Longitude
Orientation
City
Land Owner
Phone number
Site 1
: 58th street landfill
: 25:50:4.68
: 80:20:48.31
: North-South in east side
: Miami
: Miami Dade
: 3055941581
Name
Latitude
Longitude
Orientation
City
Land Owner
Phone number
Site 2
: North Dade Landfill
: 25:58:4.35
: 80:17:10.51
: East-West
: Miami
: Miami Dade
: 3055941581
3.1.3.3 Topographical Characteristics
The topography at 58th landfill is continues with no significant depressions. Most
areas of the landfill are suitable for PV implementation. The landfill was closed over than
30 years ago. Figures 33.a and 33.b present the general site view of the 58th landfill.
(a)
(b)
Figure 33. View of 58th Street Landfill
The North-Dade landfill topography and shape is in accordance to its classification. As
class III landfill the slopes settlement take longer than class I and class II landfills, waste
is mostly made by not organic waste, for that reason the shape is maintained, but there is
evidence of some deformation. This landfill is active and one cell is already closed in
1996. Since some settlement is expected, PV layout has to be considered possible
distortions in the shape. Figure 34 shows the North-Dade Landfill.
37
(a)
(b)
(c)
(d)
Figure 34. View of North-Dade Landfill
3.1.3.4 Site Compatibility
Most closed landfills are suitable for solar systems. According to landfill design
standards, most sites use slopes during the cell construction in the range between 1:3 and
1:4. Solar harvesting works in wide ranges of slopes. At 58th street landfill site, the
topography is mostly even. Some depressions in the cap were observed. These
depression can be concern at the time of construction; however, with some site work, the
areas can be made even for installation of the PV systems. Presence of corrosive gases
such as sulfide, sulfur dioxide or CFC’s at landfill sites can be a concern. However,
effective gas control systems can minimize or eliminate the corrosion concerns. At the
58th landfill there was no evidence of landfill gas. At the North-Dade landfill, gas is piped
to two engines that produce electricity for use at the site.
3.1.3.5 Type and Integrity of the Cap System
The cap is designed to protect the human health as well as control runoff, support
vegetation, manage landfill gas. A solar project which is designed on a landfill that have
been closed less than 20 years, cover stability may be a concern. During the PV
installation, cap modification should be avoided. Integrity and strength of the cover to
38
support the foundation needs of the panels structure should be analyzed. The standard
configuration for cover system to support solar panels is provided in Figure 35.
Support and high rate infiltration
layer
Aggregated or synthetic materials
Geotextile filter
Lateral drainage layer
Geomembrane
Compacted clay barrier layer
Geotextile filter
Gas collection layer
Subgrade (foundation) layer
Waste
Figure 35. Cover profile proposed to develop a PV landfill project (adapted from
LaGrega et al., 2000)
3.1.3.6 Auxiliary Equipment
The PV array by itself does not constitute the PV power system. The
complementary equipment should be provided to mount all the auxiliary devices and
components that carry the DC power produced by the solar array and transform the power
in the form that is usable by the load. For the AC load, inverter is needed to convert the
DC power to AC, normally at 50 or 60 Hz. The steps in which solar energy is
transformed and transported in a stand-alone PV system is showed in the Figure 36.
Figure 36. Basic components for a stand-alone solar system (adapted from Patel, 1999)
39
The other configuration for PV systems is to connect the solar array directly to the grid as
shown in Figure 37.
Figure 37. Mayor Components of a photovoltaic power system (adapted from Patel,1999)
A brief description of the PV system components is provided below:
Peak power tracker: Senses the voltage and current outputs of the array and
continuously adjusts the operating point to extract the maximum power under the given
climatic conditions.
PWM Controller: Provides reliable solar battery charging, load control or load diversion
regulation.
Battery Charger: Multi-stage battery chargers are microprocessor controlled for fast and
accurate charging of all deep-cycle batteries.
Charge current controller: Regulates the voltage and current from the solar panels to
the battery. Most "12 volt" panels produce about 16 to 20 volts. If there is no regulation,
the batteries will be damaged from overcharging. Most batteries need around 14 to 14.5
volts to be fully charged.
DC to AC Inverter: Converts DC current into AC current (which is suitable for
household appliances such as; e.g., kitchen appliances, microwaves, TV's, radios, and
computers).
3.1.3.7 Control of Lecheate and Gas
In the design phase, any alteration of the existing leachate and gas collection
systems should be avoided. The interference of the project with the control of leachate
and gas is not expected to be a significant concern for installation of PV systems.
3.1.3.8 Control of Vegetation and Final Grade
For installation of solar panels, placement of a soil layer may be necessary to
support the foundation system for mounting the panels. This would also reduce the
infiltration depending on the cover system. Management of water runoff over the panels
40
and the vegetative support is necessary to protect the soil from the erosion. The solar
panels may not support vegetation growth uniformly, hence alternative soil coverage
should be considered.
3.1.3.9 Site Maintenance
The maintenance of a landfill which supports a PV system is needed to protect
and maintain the landfill and the PV system in operable conditions. These activities
should be accomplished in part by the site owners and PV system operator. The
maintenance of the PV system relies on the safety, durability, and quality of the system to
be installed. Although PV systems could last over 30 years providing service, a good
design and maintenance could extend the system life. The operational and maintenance
support would consist mainly PV system inspections, maintenance and replacement of
the batteries in accordance with the National Electrical Code (NCE).
The main problems that are often encountered in PV system maintenance are:
⋅ Dirty or cracked solar panels;
⋅ Corroded electrical connectors or panels;
⋅ Short circuits and/or broken inverters;
⋅ Bird nests;
⋅ Grass and tree growth;
⋅ Panel theft.
3.1.3.10 Surface Water Control
Most common technologies that can be incorporated into the site include surface
water diversion and collection systems to minimize surface water entering the site. Water
collection is designed to prevent erosion in the cover layer i.e. grass, and it infiltrates
through the cover layer preventing going beyond the boundary where the waste is
disposed. A permeable layer transports the water through a porous media and collection
ditches conveying the water to a pond or lagoon. The shapes and structures that make up
the cover layer and water collection includes dikes and berms, ditches and drainage ways,
terraces and dirches, and chutes and downpipes (Hunn et al., 1987). A schematic of a
landfill site collection system is shown in Figure 38.
Figure 38. Typical landfill water collection system
41
The rain water strikes the solar panels and reduce some of the force that the water
exerts onto the soil without panels. However, the amount of water per unit of area to be
collected could increase. To avoid runoff, a cover layer may be needed for infiltration at a
faster rate. Alternative caps are presented in the Figures 39 and 40.
Solar Panel
Support
Collecting area
New layer to support PV system
Runoff collecting area
Existing layer
Figure 39. A simplified cover layer to control runoff in the PV system for a landfill site
(adapted from Lagrega, 2001).
Vegetation
Vegetative Support
Geotextile filter
Lateral drainage layer
Geomembrane barrier
Compacted clay barrier layer
Geotextile filter
Gas collection layer
Subgrade (foundation) layer
Waste
Figure 40. Cover system (adapted from Lagreaga, 2001).
Plastic or polymer layer
Support and high rate
infiltration layer
Geotextile
Lateral drainage layer
Geomembrane barrier
Compacted clay barrier layer
Geotextile filter
Gas collection layer
Subgrade (foundation) layer
Waste
Figure 41. A proposed cover layer system for a Landfill site with PV system
42
In Figure 41, the first layer of the cap system is proposed to be a polymer because
of its light in comparison to gravel, hence it would not affect the stability of the landfill.
Use of recycled materials can be considered for this application.
3.1.3.11 Infrastructural and Auxiliary Structures Needs
The photovoltaic power system requires some infrastructure to support the main
components of the system. Within the infrastructure, the cover system which was
described in sections 3.1.3.5 and 3.1.3.11, would support the structures and the solar
panels. Supports are the main structures that hold the panels if they are placed at tilted
configurations. When the panels are placed directly over the ground, they need to be
anchored to the supports which are held by a foundation. The supports need to be tested
for resistance under the worst scenarios, in general heavy wind loads. Other auxiliary
equipment was described in section 3.1.3.6.
3.1.3.12 Energy Generation Potential
Sites located in areas with latitudes above 30 degrees have higher energy potential
(e.g., Florida, Arizona, New Mexico, Texas, and California). Florida is placed under the
“very good” classification for solar energy generation potential with average capacity of
> 5-6 kWh/m2 (http://www.epa.gov/renewableenergyland/maps_incentives.htm).
3.1.3.13 Integration to the Grid
Since PV stand-alone systems have been in demand, bigger projects that can be
connected to the grid are desirable to control flow shortages and provide power.
Interconnection to the grid requires appropriate synchronization with the grid current,
voltage, and frequency. The performance analysis has to be carried out in the economical
assessment in order to evaluate the best alternative for a specific site.
3.1.3.14 Mitigation of Power Shortages
Power shortages could happen when either shadow is present or the energy output
is lower than the energy needed. In both scenarios, the power shortage need to be
equalized. The energy yield fluctuation during the day for a PV system should meet the
short-term peak demand without withdrawing energy from the grid and paying for the
demand. Batteries are used in the PV systems to avoid these temporary power shortages.
The current in PV system fluctuates during the day, and is appreciable as the sun moves
during the day in its own path and solar radiation changes are noticed. A typical hourly
fluctuation of energy is shown in Figure 42. As the PV current is DC current the inverter
converts the DC to AC, and the batteries are used to equalize the flow, then shortages to
recharge the batteries and overages to deliver in the system are avoided.
43
300
250
Watts/panel
200
FLAT
Tilted
150
Poly. (FLAT)
100
50
0
13
23
33
43
53
Time stamp
63 2
73
y = -0.1986x + 15.798x - 77.411
2
R = 0.9728
Figure 42. Typical current fluctuation in the 58th landfill
3.1.3.15 Corrosion Potential
The corrosion potential depends on the composition of the landfill gas and the
reaction of materials with moisture. Composition of landfill gas varies from site to site,
and at one specific site from one area to another. Average composition of landfill gas is
provided in Table 10.
Table 10. Typical landfill gas composition (Tchobanoglous, et al., 1993)
Typical Landfill Gas
% (dry volume basis)
Methane
45-60
Carbon Dioxide
40-60
Nitrogen
2-5
Oxygen
0.1-1.0
Sulphides, disulphides,
0.1-0
Ammonia
0.1-1.0
Hydrogen
0-0.2
Carbon Monoxide
0-0.2
Trace constituents
0.01-0.6
The reaction of landfill gas with the soil moisture generates new compounds
which may dissolve in water. The reaction of hydrogen sulphide and sulphur dioxide
creates corrosive substances that decrease the lifespan of the monitoring equipment and
structures exposed to the gas. For Solar panels, no research data are available about the
corrosion potential due to landfill gas. For site assessment, corrosion potential will be
addressed in terms of corrosive gas contents, and then normalized in the specific case
scenario selected. At the sites where gas is piped to a flare or a gas recovery unit, were
evaluated favorably.
44
3.2 SOLAR ENERGY GENERATION ON LADNFILLS
3.2.1 Criteria for Screening of Solar Technology Suitability on Landfills
Important factors to be considered for screening solar technologies for use on
landfills are provided in Table 11. Table 11 also presents the assigned values with
appropriate weighs (0 to 100%) and the overall scores given on a scale of 1 to 10 for each
technology.
Cost: Solar panel availability with low cost and considerable efficiency make the project
economical. Hence, a weight of 20% was assigned to this factor and scores are given
based on the efficiency level with respect to cost.
Wind & Snow Effects: Panels should be capable of resisting loads contributed by heavy
winds (or snow/ice in colder areas) loads to avoid damage to the panels. Hence, a weigh
of 10% was assigned to this factor and scores are based on wind load on the panels.
Shading Effect: Panels with high efficiency levels at the lower sunlight intensity (i.e., on
partly cloudy days) have better service reliability. Hence, a weight of 10% was assigned
to this factor and scores are given based on the panel performance at low levels of
sunlight.
Foundation Requirements: Placement of solar systems over landfills requires suitable
foundation to support the weight of the panels and mounting systems without disturbing
the landfill cover. Hence, this factor was assigned a weight of 20% and scores are given
based on foundation requirements.
Maintenance & Replacement: In general, panels lose about 6% efficiency every year
and replacement might contribute an additional costs. Proper maintenance of the panels is
required to maintain good efficiency levels over the life time. Hence, a weight of 15%
was assigned.
Efficiency/Unit area: Generating higher efficiency per unit area provides more energy
per unit area. Hence, weight of 25% was assigned.
3.2.2 Available Solar Insolation and Sunny days/year for Florida
3.2.2.1 Solar Insulation
The amount of solar radiation received on to the earth’s surface varies depending
upon the solar angle, atmospheric state, altitude and the geographic location, and time of
the day. Solar insolation is measured as amount of solar energy coming to the earth’s
surface per square meter on a single day and is expressed as Kwh/m2/day
(http://www.solarpanelsplus.com/solar-insolation-levels/). In Florida (at about sea level),
an object will receive a maximum of about 22.8 Kwh/m2/day (950 watts/m2 or 90
watts/ft2) at high noon on a horizontal surface under clear skies on June 21 (day of the
summer equinox) (FSEC, 2006).
Florida is located in Zone 4 of Solar Insulation map, receiving 4.5 peak sunshine
hours/day on an average/year (http://www.wholesalesolar.com/Information- SolarFolder/
SunHoursUSMap.html). Tables 12, 13 and 14 provides the solar insolation values,
45
available sunny days and possible average sunshine percentages observed over years at
selected locations in Florida. Lowest values of solar insolation were used for conservative
year-round estimates (i.e., to provide power for periods of reduced sunlight due to
inclement weather) and highest values are chosen for the summer months
(http://www.solarseller.com/solar_insolation_maps_and_chart_.htm).
Table 11. Screening solar technology suitability on landfills
WIND EFFECT
SHADING EFFECT
FOUNDATION REQUIREMENTS
MAINTENANCE & REPLACEMENT
EFFICIENCY/UNIT AREA
20% (Cost)
10% (Wind)
10% (Shading)
20% (Foundation)
15% (Maintenance)
25% (Efficiency)
PHOTOVOLTAIC
TECHNOLGY
TOTAL
Score*
Rigid Panels
7
7
6
7
5
9
1.4
0.7
0.6
1.4
0.75
2.25
7.1
Flexible Panels
9
10
9
10
7
6
1.8
1
0.9
2
1.05
1.5
8.25
Linear
Concentrator
Systems
5
6
5
3
2
9
1
0.6
0.5
0.6
0.3
2.25
5.25
Dish / Engine
Systems
3
5
5
5
3
5
0.6
0.5
0.5
1
0.45
1.25
4.3
Power Tower
Systems
1
3
5
1
1
9
0.2
0.3
0.5
0.2
0.15
2.25
3.6
TECHNOLOGY VS
FACTORS
SOLAR THERMAL
TECHNOLOGY
WEIGHT
COST
CHARACTERISTIC INPUTS
* Score = 1 to 10 with values close to 10 are most suitable for solar harvesting
10= Best ; 7= Above average; 5= Average; 3= Below average; 1 = Unsuitable
Table 12. Solar insulation values for various locations in Florida
(http://www.wholesalesolar.com/Information-SolarFolder/SunHoursUSMap.html)
Location
Low
High
Average
Apalachicola, FL
4.92
5.98
5.49
Belie Island, FL
4.58
5.31
4.99
Gainesville, FL
4.71
5.81
5.27
Miami, FL
5.05
6.26
5.62
Tampa, FL
5.26
6.16
5.67
46
Table 13. Averagely available clear (sunny days), partly cloudy and cloudy days in a year
(http://lwf.ncdc.noaa.gov/oa/climate/online/ccd/cldy.html)
Years taken
for average
62
52
54
47
43
46
47
29
34
49
48
Location
Apalachicola, FL
Daytona Beach, FL
Fort Myers, FL
Jacksonville, FL
Keywest, FL
Miami, FL
Orlando, FL
Pensacola, FL
Tallahassee, FL
Tampa, FL
West Palm Beach, FL
Sunny
(days/year)
128
97
98
94
104
74
89
105
102
101
75
Partly cloudy
(days/year)
113
132
168
127
155
175
147
123
129
143
159
Cloudy
(days/year)
116
136
99
144
107
115
130
137
134
121
131
Table 14. Possible average sunshine percentages for certain locations in Florida
(http://www.ncdc.noaa.gov/oa/climate/online/ccd/avgsun.html)
Location
No Years
for average
January
February
March
April
May
June
July
August
September
October
November
December
Annual
Apalachicola
57
58
61
65
74
77
71
64
64
66
74
67
57
66
Sunshine - Average (%) possible
Jacksonville Keywest
Miami
50
58
62
68
73
70
66
65
64
58
60
60
54
63
38
74
77
82
84
82
76
77
76
72
71
71
70
76
20
66
68
74
76
72
68
72
71
70
70
67
63
70
Pensacola
Tampa
5
48
53
61
63
67
67
57
58
60
71
64
49
60
50
63
65
71
75
75
67
62
61
61
65
64
61
66
3.2.2.2 Solar Energy Impacts on Florida
Florida could become the second largest producer of electricity using solar
resources after California with currently 100 MW’s of electricity projects under
construction. Solar energy can be an eco-friendly technology by providing employment
opportunities, tax payer incentives and forward thinking for energy policies (Florida Tax
Watch, 2009).
47
Harvesting of solar energy in Florida includes the following benefits (Florida Tax Watch,
2009):
1. Florida has feasible sunshine hours available. On average, the number of days
with sunshine in Northern Florida is about 361, which is higher in the southern
part of the state.
2. Florida has trained work force necessary for solar industry in the form of
residential and commercial construction industries which can create additional
jobs by the construction activities of the solar facilities.
3. There is collaborative work with universities, community colleges, technical
institutes, work force agencies and industries forming into associations namely
University of Central Florida’s Solar Energy Center and University of Florida’s
Florida Institute of Sustainable Energy, which are established in educating people
about solar technologies, promoting the growth of solar energy applications in the
state, contributing new talents to the industries, providing necessary information
and scope for further research.
4. Both national and international manufacturers of solar technologies are
considering Florida as one of the attractive and beneficial markets in the United
States for permitting and building new facilities. Historically, the Florida Public
Service Commission has been open to innovation for attracting investment.
3.2.3 Design Approach for a Tilted Surface Model
The existing radiation data is mostly for solar radiation on horizontal flat plate
surfaces. The relationship between the solar radiation on a horizontal surface was used to
estimate the radiation on a tilted one through the R factor which is described further in
this section was considered. If data is available, a model that corrects the energy yield
from flat plate surface to a tilted one was developed. Furthermore, it was assumed that
fraction of radiation that is reflected from the ground is uniform in all directions and the
effect of the atmosphere was ignored since the data is the an average of the actual
irradiance. Isotropic diffuse model reported by Liu and Jordan (1963) was used as it is
the most conservative of the models and relatively simplest to use.
3.2.3.1 The Isotropic Diffuse Model
A flat surface with a tilted angle β is considered to receive three different sources
of sunlight as follows: the radiation diffused from the ground, sky radiation and the beam
radiation. For any particular hour on a horizontal flat plate, total radiation received is:
I T = I BT + I DT + I GT
(1)
where,
IT
: Total radiation
48
IBT
IDT
IGT
: Beam radiation contribution
: Diffuse radiation contribution
: Ground radiation contribution
The intercepted beam radiation IBT is:
I BT = I B RB
RB
(2)
: Beam tilt correction factor.
The angle of incidence θ has to be corrected for tilted surfaces. A correction
factor has been developed by Thacher (2005) which related the area of the plate and the
cosine of the angle of incidence. Radiation flow rate at which the plate is intercepted is:
Qtilted = Go AP = Go A cos θ
where:
(3)
Qtilted : Radiation flow rate (W/m2-h)
Go
: (1373 W/m2)
A
: Plate area
Since the line perpendicular to the horizontal surface would be pointing at the local
zenith, hence θ = θZ. Then:
Qhorizontal = Go AP = Go A cosθ Z
(4)
The beam correction factor will be the ratio of the radiation on a tilted surface to that on a
horizontal surface at the same location and time as:
Qtilted
cos θ
=
= RB
Q Horizontal cos θ Z
(5)
The intercepted sky diffused radiation is:
1 + cos β
(6)
2
where cosβ is the fraction of solar radiation that is taken from the sky.
I DT = I D
The ground-diffused radiation is the amount that is not received from the sky:
1 − cos β
(7)
2
For the tilted surface, from equations 2-7, equation 1 can be expanded as:
Iρ G = I D
49
I T = I BRB + I D
1 + cos β
1 − cos β
+ Iρ G
2
2
(8)
The total radiation (flat or tilted) on a surface can be estimated.
3.2.3.2 Solar Data
The solar radiation interacts with any surface, hence is necessary to understand
simultaneously the variability of the earth motion and the effect of the sky and ground
diffused radiation. Hence, it is necessary to consider the solar radiation available for a
reasonable length of time.
One of the most widely used data sources for solar radiation is the National
Radiation Data Base (NRDB). This data base includes solar radiation data in a typical
meteorological year (TMY) and is derived from the actual data collected during 19611990 and 1991-2005 from the National Solar Radiation Data Base (NSRDB) archives.
The new TMY3 data sets include updated data. The TMY3 data set contains data for
1020 locations, compared with 239 for the TMY2 data set. In the TMY3 that is last
version after the improvements of TMY and TMY2. There are sets of hourly data for
solar radiation and meteorological elements. The TMY3 data sets are produced by
NREL's Electric Systems Center under the Solar Resource Characterization Project,
which is funded and monitored by the U.S. Department of Energy's Energy Efficiency
and Renewable Energy Office.
3.2.3.3 Source Data
The TMY data sets provide annual hourly radiation values for a specific location
over a long period of time, 1961-1990 from NRDB, and later in 2007, NREL more data is
released with 15 years updated NSRDB for 1991-2005 (Wilcox et. al., 2007). TMY3 is
obtained from an empirical statistical process called the Sandia method. In this method a
360 months (30 years) set data is analyzed to obtain the most representative year.
Individual months for different years are selected in the period of record. For example, in
the set of 30 year of data, 30 Januarys are selected and examined, and the one judged as
most typical and selected to be included in the TMY3.The 12 selected typical months for
each station were chosen using statistical analyses and determined by considering five
elements: global horizontal radiation, direct normal radiation, dry bulb temperature, dew
point temperature, and wind speed. These elements are considered the most important for
simulating solar energy conversion systems (Marion and Wilcox, 2008).
3.2.3.4 Data Format
The TMY3 data format contains two file header lines and 8,760 lines of data, each
with 68 data fields. The data format is briefly summarized in Tables 15 and 16.
50
Table 15. Data header (Marion and Wilcox, 2008)
Field
1
2
3
4
5
6
7
Element
Site identifier code
Station name
Station state
Site time zone
Site latitude
Site longitude
Site elevation
Unit or Description
USAF number
Quote delimited
Two-letter U.S. Postal abbreviation
Hours from Greenwich, negative west
Decimal degree
Decimal degree
Meter
Table 16. Data fields (Marion and Wilcox, 2008)
Field
Element
1
Date
2
3
5
Time
Angle of incidence (θ), for
horizontal flat plate
surface
Angle of incidence at a (β)
angle for horizontal flat
plate surface
Zenith angle (θZ)
6
R
Ratio
7
Solar time (ω)
Degrees
8
Declination angle (δ)
Degrees
9
Solar altitude (ε)
Degrees
10
Total solar radiation
W/m2-h
11
Global horizontal
irradiance
Watt-hour per
square meter
12
Direct normal irradiance
Watt-hour per
square meter
13
Diffuse horizontal
irradiance
Watt-hour per
square meter
4
Unit or
Range
MM/DD/YYY
Y
HH:MM
Degrees
Degrees
Degrees
51
Description
Date of data record
Time of data record (local standard time)
Angle between direct solar beam and a line
normal to the irradiated surface, when
θ=θZ, β=0
Angle between direct solar beam and a line
normal to the irradiated surface, when β≠ 0
The angle between the projection onto a
horizontal plane of a line to the sun and the
normal to the irradiated surface
Beam tilt correction factor given by the
ratio of cosθ/cosθZ
The sun’s position measured east or west
of true solar south
Angle between the earth-sun line at solar
noon and the earth’s equatorial plane
The angle between the horizontal plane
and direct solar beam
Total radiation received on tilted flat
surface
Total amount of direct and diffuse solar
radiation received on a horizontal surface
during 60-minute period ending at the time
stamp
Amount of solar radiation (modeled)
received in a collimated beam on a surface
normal to the sun during 60-minute period
ending at the time stamp
Amount of solar radiation received from
sky (excluding the solar disk) on a
horizontal surface during 60-minute period
ending at the time stamp
3.2.3.5 Radiation on a Flat Plate Tilted Surfaces Model
Most information available for photovoltaic’s applications is for horizontal flat
plate surfaces. There is limited analysis for tilted surfaces. The TMY data by the NRDB
was used to model scenarios with different tilted angles. To develop conversion tool (flat
to tilted), the interaction the motion of the sun thought the year was considered for use of
the TMY data.
The discerning of how solar motion affects the earth’s surface is fundamental to
understand the changes over the time of the different amount of solar radiation that
reaches the planet (e.g., on March 22nd, at the Miami International Airport, the sunlight
strikes the earth at the most perpendicular angle possible for this location). The
information available in the NSRDB was filtered, keeping only the information that is of
interest. Table 11 presents the filtered information used for analyses. In the NSRDB,
most of the information is for meteorological measurements and uncertainty factors. The
data provided by NSRDB is 68 columns. Only the data that will be input to the model
was extracted (i.e., rows 11, 12 and 13 in Table 16, to obtain the main solar geometry
represented in the rows 3 to 10) to estimate the values for tilted surfaces.
3.2.3.6 An Empirical Model for Tilted Surfaces
An empirical model was constructed based on the TMY3 data, consisting in 8760
files. It was created one spreadsheet for each type of angle, starting with 0 degrees as
horizontal flat plate surface, and increasing by 10 degrees until it reaches a maximum
tilted angle of 90 degrees. The explanation of the angles is provided in the solar angles
section of the report. A specific location in Florida was selected amongst the 1020 solar
radiation stations located around the USA for TMY3. The station characteristics are
presented in Table 17.
Table 17. Station selected in TMY3 data records provided by NSRDB
(http://rredc.nrel.gov/solar/old_data/nsrdb/1991-2005/data/tmy3/722020TY.csv)
Site state
Site name
Site identifier code
Surface Tilt Angle
Site elevation (m.o.s.l.)
Site longitude (degrees)
Site latitude (degrees)
Site time zone
Florida
Miami International Airport
722020
0
11
-80.3
25.817
-5
The NSRDB update subdivided stations by class; Miami International Airport is
classified as Class I, meaning this site has the lowest uncertainty in data. It is important to
clarify that this empirical model is for tilted surfaces towards the south. The north, west,
and east facing surfaces have to be considered under specific conditions (i.e., particular
shadow parameters and angles of incidence). The TMY3 data is displayed as hourly
52
average of solar radiation, hour by hour in 24 hours (i.e., it is compiled calculating
average per day, and per month, and finally per year). The daily averages, 365 in total
were compressed for the yearly average for different tilted flat surfaces. The TMY3 data
sets that were selected are described below:
Global horizontal irradiance: Total amount of direct and diffuse solar radiation
received on a horizontal surface during the 60-minute period ending at the timestamp.
Direct normal irradiance: Amount of solar radiation (modeled) received in a collimated
beam on a surface normal to the sun during the 60-minute period ending at the
timestamp.
Diffuse horizontal irradiance: Amount of solar radiation received from the sky
(excluding the solar disk) on a horizontal surface during the 60-minute period ending at
the timestamp.
3.2.3.7 Results
The output from the empirical model is displayed in the Figure 43. Due to the
changes in the earth’s axis, the flat plate surface reaches a maximum value between the
March and April, when the latitude of this location close to perpendicular to the sun’s
position. The results show that 20 degrees tilted surface is more efficient than the others.
To understand the effect of the solar altitude, the sun path diagram through the year
presented in Figure 44. For example, in winter the maximum solar elevation occurs at
noon, and the empirical model predicts about 41 degrees as presented in Figure 45.
Radiation on a flat plate surface at different tilted angles
600
0
10
400
20
30
300
40
50
60
200
70
80
100
90
O
ct
ob
er
N
ov
em
be
r
D
ec
em
be
r
t
m
be
r
Se
pt
e
Au
gu
s
Ju
ly
Ju
ne
M
ay
Ap
ril
M
ar
ch
0
Ja
nu
ar
y
Fe
br
ua
ry
radiation W/hr-m2
500
Month
Figure 43. Radiation on a flat plate surface at different angles
53
Figure 44. Solar altitude
Solar beam
Normal
θ = 39°
41° ε
20° β
Figure 45. Winter maximum sun elevation at a 20° tilted surface
When the surface is 20 degrees tilted, in winter, the angle of incidence is at 41 degrees
from horizontal and 39 degrees from normal. Then, R can be estimated as:
R=
cos( 39 )
= 1.18
cos( 49 )
Figure 46. presents the angle of incidence for 50 degrees tilted surface at 1degrees during
winter when the sun is at 41 degrees. The, R becomes:
R=
cos(1)
= 1.52
cos( 49 )
54
θ = 1°
Solar beam
Normal
41° ε
50° β
Figure 46. Winter maximum sun elevation at a 50° tilted surface
For tilted surfaces, it was realized that radiation efficiency is better at 50 degrees
tilt angle than 20 degrees tilt angle (e.g., 100 W/m2 in winter for a tilted surface of 20
degrees becomes 118 W/m2, but in the case of 50 degrees tilted surface it would be 152
W/m2, being more efficient at 50 degree tilt angle) validating the data in Figure 44.
Accordingly with the empirical model, the maximum sun elevation in the summer is
around 87.63 degrees. Figure 47 is displays an angle of 20 degrees at the tilted surface,
for this specific configuration.
Solar beam
Normal
θ = 17.6°
ε 87.63°
20° β
Figure 47. Summer maximum sun elevation at a 20° tilted surface
Then R becomes:
R=
cos(2.37)
= 1.048
cos(17.6)
Figure 48 displays an angle of 50° at tilted surface, for this specific configuration.
Normal
θ = 47.63°
Solar beam
87.63°
ε
50° β
Figure 48. Summer maximum sun elevation at a 50° tilted surface
55
R=
cos( 47.63)
= 0.70
cos(17.6)
The values of R for the summer on tilted surfaces at 20 and 50 degrees are 1.048
and 0.7, respectively (i.e., 20 degrees tilt angle is 33% more efficient at noon than 50
degrees tilt angle), which contrast with the results displayed in Figure 45.The result of
this analysis could be displayed also in the Figures 43 and 44 present the amount of
energy received by a surface at different tilt angles, for a zenith angle of 0°. The ideal
approximation of the model represents the geometric position of the sun. The Figures 45,
46 and 47 presenting the hourly conditions predicted by the model. The model provides a
good approximation of the flat plate surfaces at any tilted angle. The empirical model was
adequate to understand the behavior of tilted surfaces for a zenith angle of 0 degrees.
Different zenith angles should be considered for future studies as well as the shadow
effects on surface that are not facing the south.
3.2.4 Solar Photovoltaic Power System
The photovoltaic system was developed by the French physicist Becquerel in
1839, who converted the photovoltaic effect to energy. Today PV systems have numerous
applications. For this study, two main configurations of the PV power system were
considered: 1. Grid connected, and 2. Stand alone systems which are described below.
3.2.4.1 Stand Alone System
Stand alone systems are suitable for remote areas since installation of utility lines
are uneconomical. The utility lines cost about $1 million/mile for a 230 kV line. The
feasibility of stand alone systems depend on the energy demand, distance from customers
and distance from the grid. The energy storage is also needed due to the oscillations in
between low or no power output. A typical stand alone system consists of solar array,
battery connections and the inverter to convert the DC to AC current from the array.
3.2.4.2 Stand-alone versus PV Grid Line
In those remote areas where the wind is not a suitable source of energy and the
grid is not feasible; the customers have two options: 1. Extend the utility line, or 2. Install
a PV power system. To help in the decision, the Idaho Power company developed a graph
to assess the feasibility of extending the line or installing a PV system in term of distance
and demand as shown in Figure 49. In the Figure 49 the darker are means evaluate PV
system and the lighter side means evaluate line extension. The horizontal values are
kilometers and the vertical are in kWh/day.
56
Demand (kWh‐day)
Distance (kilometers)
Figure 49. Stand-alone PV or line extension cost (Patel, 1999)
3.2.4.3 Grid-connected System
Currently with the demand for new clean sources of energy, the number of gridconnected systems have been increasing. Hence, pooling the sequential overload or the
deficit in the renewal power with the connecting grid improves the overall economy and
the load availability of the renewable plant. This allows synchronization of the load
fluctuations in a deficit-excess cycle with the plant.
3.2.5 Energy to Be Generated In Closed Landfills by PV System
The amount of energy to be generated is proportional to the area to place the PV
systems. In South Florida (specifically in Miami), the baseline results are estimated and
summarized in Table 18 for energy yield for a surface tilted 18 degrees relative to a
horizontal surface. The south and horizontal positions have the highest number of sunny
hours during the year even if they do not have the highest solar radiation rates. Figure 50
presents the changes in energy yield with orientation of the panels.
Table 18. Standard Energy Yield for a place within the Miami Dade area.
TMY hourly
Energy yield
Orientation
Average
Area
Radiation average
2
per Kw/hr
surface area
Hours /year
m
(kw/hr)
East
408.12
3631
1
408
West
425.70
4184
1
426
South
396.17
4615
1
396
North
417.30
3343
1
417
Flat
375.312
4615
1
375
57
250.00
200.00
150.00
W/h-m2
100.00
50.00
0.00
East
West
South
North
Orientation
Flat
Energy yield per W/h-m2
Figure 50. Energy yield and orientation
Solar energy generation on landfills in South Florida depends on the site location,
and orientation and lay out the PV modules. Total energy generation calculations are
provided in Appendix A and B.
3.3 FOUNDATION REQUIREMENTS AND DESIGN
3.3.1 Factors Considered For Solar Energy Systems Placement
Technical feasibility of solar energy harvesting on landfills depends on
compatibility of the PV systems with the existing landfill components. Figure 51 presents
the placement of solar systems on top and sloped surfaces on landfills.
N
W
E
Sun
S
Solar panels
Figure 51. Placement of solar panels on horizontal and sloped surfaces on landfill.
3.3.1.1 Wind Load and Snow Load Considerations
Figure 52 presents the wind speed chart for Florida based on the “3-second-peakgust method” of Exposure “C” category at 33 feet above ground level (as required by
Florida Building Code). Wind loads increase the stress on the supporting structures by
adding weight onto the solar panels and components, resulting in the failure of the solar
energy system. Accumulation of ice and snow adds additional weight onto the system
58
thereby increasing the stress on the foundation. Figure 53 provides how the wind loads
are exerted on solar systems with respect to wind direction facing normal to the panel.
Figure 52. Wind speed chart for Florida (3-second-peak-gust method)
(http://web.dcp.ufl.edu/stroh/FloridaBuildingCode.pdf,
http://www.brobinsoncorporation.com/WindLoads.html)
59
Figure 53. Effect of wind loads on solar systems based on wind direction (Imaginary).
In general, wind speeds of 105 miles/hr is taken as the standard for the crystalline
and amorphous thin film cell categories based on the industry standards set by
International Electro technical commission codes (61215 and 61646), which equals to
mechanical loading of 50 pounds per square foot (Sampson, 2009). Hence, for hurricane
prone regions such as Florida and regions effected by snow, mounting systems capable or
certified for resisting higher mechanical loadings, approved by solar installers need to be
considered. Some landfills require regular top surface maintenance and demand the
placement of mounting structures high enough to support the maintenance activities (i.e.,
mowing grass). These high rise systems are easily affected by increased weight and
stress caused due to high wind loads and longer pier lengths and should be supported by
strong foundation (Sampson, 2009). Remedial measures for the effects of wind loads and
snow loads on solar systems should also be considered.
3.3.1.2 Side Slope Stability
Placement of panels on sloped surfaces (especially south facing slopes at higher
altitudes), can achieve maximum solar radiation (Sampson, 2009). Installation of panels
60
on side slopes can be challenging for ensuring good foundation support, protection from
erosion, storm water control, shading effects, settlement effects. Slopes larger than 5
degrees are largely affected by the above factors. In addition, regular operation and
maintenance activities could increase for side slope repairs resulting in additional costs to
the project. Remedial measures such as vegetative surfaces and engineered retaining
walls can reduce erosion effects (Sampson, 2009). Slope instabilities decrease with time
as waste decomposition rates slow down (Sampson, 2009). For landfills with steep
slopes, re-grading and use of additional top soil can help achieving suitable slopes
capable of supporting solar systems placement (Sampson, 2009). In general steep slopes
demand strong foundations (i.e., poured concrete or pre-cast concrete footings) with light
weight solar components. Hence, light weight solar components of appropriate
mechanical loading rates with strong foundation is preferred at sloped surfaces, which are
capable of resisting wind loads, additional load requirements produced by snow or ice (if
any). It is also necessary to perform slope stability assessment prior to construction
activities to ensure integrity of cap and adequate slope stability can be maintained
(Sampson, 2009).
3.3.1.3 Landfill Settlement and its Effects
Physio-chemical, mechanical and bio-chemical processes change properties of
disposed waste over time and cause settlement. Landfill settlements over time could
result in formation of surface cracks to the final cover, damages to the leachate and gas
collection piping, water drainage systems and underground utilities, formation of waterholding depressions (Sampson, 2009).
Settlements processes on landfills are classified as:
1. Active settlement: The amount of active settlement depends on type of wastes
deposited, depth of waste layers, methods of placement, and age of landfill
(Sampson, 2009).
2. Immediate settlement: Rapid mechanical compression of disposed waste results in
immediate settlements (Sampson, 2009). Immediate settlements promote crack
formations of the foundations and damages to landfill cap. Application of heavy
loads during site preparation activities (i.e., heavy machinery and equipments),
during solar system installation promotes immediate settlements. Remedial
measures to distribute the loads more uniformly on the landfill cap or controlling
the construction traffic can reduce immediate settlement (Sampson, 2009).
3. Differential settlement: Differential settlements are localized sinks or
deformations on the landfill surface due to different mix up of the buried waste.
From a geotechnical perspective, differential settlement could cause significant
problems for the integrity of the structures on landfills. For solar energy
component installation, differential settlement could damage footings, array piers,
electrical lining and can disrupt the position of solar systems orientation facing
the sun (Sampson, 2009).
61
Reducing settlement effects: Dynamic compaction is is applied as controlled tamping of
loose soils to raise or promote densification. For landfills, dynamic compaction can
increase the material density and decreases the differential settlement (Sampson 2009).
Waste removal and replacement with the clean fill could improve landfill densification.
These procedures are generally considered before the landfill closure. For development of
previously closed landfill cases, application of geo-grid reinforcement can increase the
cover soil strength placed above the geo-membrane. Use of adjustable solar system
components (i.e., shims and adjustable racking systems of solar mounting structures) can
resist against the changes in the landfill deformations (Sampson, 2009).
3.3.1.4 Shading Effects
Maximum energy generation from the solar energy harvesting systems can be
attained or obtained by minimizing the shading effects on the panels. Solar system arrays
should be placed with adequate spacing to avoid shading effects and for placing balance
of system components (i.e., inverters, wiring, combiner boxes). For instance, Holmes
road landfill adopted 15 acres/MW to avoid shading effects and installation of necessary
balance of system components (SRA, 2008).
Shading effects on the panels in winter can be minimized using the general thumb
rule which states that the distance between the back of one row and the front of the next
row should be 2½ times the maximum height of the front row, with the modules tilted up
at their highest angle. Based on the site characteristics, it is necessary to take into account
the lower position of the sun in the sky without being blocked by the surrounding
buildings or trees (http://unirac.com/faq/faqs-installing14.php). Table 19 presents
information regarding the distance calculations between the module rows and the
approximate sun angles below which the back row panels are shaded, which can be
considerable for winter altitudes.
Table 19. Shading angle calculation for panels in winter season
(http://unirac.com/faq/faqs-installing14.php)
Distance calculation between back of front Approximate sun angle below which
module row and front of next module row
back modules start to get shaded
2 x maximum height of front module
26 degrees
2.5 x maximum height of front module
22 degrees
3 x maximum height of front module
18 degrees
4 x maximum height of front module
14 degrees
3.3.1.5 Solar System Weights and Foundation Considerations
Weights of the solar panels and mounting structures selected for the project have
a greater significance over solar harvesting system installations on the landfill cap.
Monocrystalline, polycrystalline and pmorphous thin film cells exist in the market with
varying weights, efficiency levels and cost. Mounting and foundation structures
62
supporting the solar panels vary depending on the self-weight of the panels, additional
loads due to wind or snow or ice, side slope stability, and settlement effects.
Monocrystalline panels are more expensive and heavier than other. They are
capable of generating high efficiency in power production per unit area. Both
monocrystalline and polycrystalline panels (also referred as rigid panels) necessitate rigid
frame mountings to prevent cracking (Sampson, 2009). Because of the output advantage
of the rigid panels over thin film panels, rigid panels are preferred where there is space
limitation.
Amorphous thin film cells (also known as flexible panels) are generally lighter,
lower in cost, have lower efficiency for power production per unit area. These panels are
preferred for the situations where weight is a concern or there exists a problem or
complication in providing good foundation due to side slopes. Recent technologies in the
amorphous thin film cells (i.e., Uni-solar model PVL flexible laminate amorphous thin
film cells) were successfully implemented on sloped surfaces by attaching the PV strips
directly to the geo-membrane of the landfill cap. As the PV strips were capable of
producing high output per unit weight basis and do not require mounting structures and
foundations, they were successfully used on slope surfaces (18 degrees) on Tessman road
landfill and reduce side slope erosion concerns.
For the mounting structures and foundation materials associated with solar
systems, tacking systems have higher self weight than fixed systems. Hence, tracking
systems require good foundations with deeper piers and footings and sometimes
supported by pre-cast concrete footings (Nellis Air Force Base single axis tracking
systems). Deeper piers if used as foundation support, could increase the weight on the
landfill, increase settlement or subject to side slope stability issues (Sampson, 2009).
Landfill cap depth needed to support the PV system depends on the dead weight loads
contributed by the piers and footings (SRA, 2008). Choice of suitable PV system depends
the weight of the system (i.e., tracking systems heavier than fixed tilt systems), type of
waste and its properties, and side slope stability (Sampson, 2009). In general, flat
surfaces have less foundation requirements than sloped surfaces and can be preferred for
crystalline silicon solar cells (heavy weight) with suitable foundation (i.e., ballast
systems) for maximum energy production. For sloped surfaces, lighter panels with strong
foundation should be considered (i.e., pre-cast or poured concrete footings) are preferred
(Sampson, 2009).
3.3.1.6 Maintaining Integrity of the Cap System
Maintaining the integrity of the cap is both engineering and regulatory concern.
Clearing, filling, grading, compaction activities are generally performed during the
development of the landfill for PV system installation. During installation of solar
panels, extreme care is necessary not to damage the landfill cap or expose the waste. If
the site is heavily vegetated, thinning of vegetation may be necessary (Sampson, 2009).
Installation of solar systems on landfills require good foundation for solar systems
placement, which depends on landfill cap characteristics to support the footings.
63
Generally, during the planning stage, the cap design must consider anticipated loads by
the PV system and its components.
For most cases, prefabricated concrete piers or concrete slabs could be sufficient
enough to support a solar system. Cap-penetrating pilings would be unnecessary and
expensive in considering permitting and capital expenses for relatively low impact
developments such as power parks (Sampson, 2009). Also, requirements for trenching
activities (i.e., 24” for electrical lining), existing or future landfill gas-to-energy recovery
infrastructures should be considered (Sampson, 2009). Adequate soil layer should exists
for trenching activities (i.e., 24” minimum of soil is required to trench for electrical line
placement) with no or minimal impact on clay or geo-synthetic liner (Messics, 2009,
Sampson, 2009). If the landfill requires regular top surface (cap) maintenance (i.e.,
mowing of grass) and placement of structures high enough for the operation of mowing
equipment beneath the structures should be considered. Hence, a strong foundation is
necessary to support the increased weight and stress of the system caused by longer pier
lengths and increased wind loads (Sampson, 2009). Using short grasses for vegetation
may be preferred to decrease the mowing activities and avoid the disturbance to panels.
3.3.2 Challenges in Using Closed Landfills For Solar Energy Generation
Table 20 summarizes the potential challenges and remedies at landfills sites for
installation of solar panels. For example, Tessman Road Landfill case scenario employed
flexible PV laminates side slopes (18 degrees) directly attached to the exposed geomembrane cover. Application of exposed geo-membrane cover with light weight panels
(flexible PV strips) was a remedy for problems associated with steep side slope. In the
case of Pennsauken Landfill Project, New Jersey; shallow pre-cast concrete footings were
used to provide strong foundation for the PV system on the sloped surfaces overcoming
complications of side slope installation. This facility used ballast foundation with
crystalline panels on top surfaces for maximum energy production.
3.3.3 Site Preparation Needs for Panel Installation
The depth of the soil cap necessary to support the foundation is generally
determined during the design phase. The site preparation activities at closed landfill sites
may include:
1. Site clearing (i.e., trees, brush, and overgrowth removal) for placement of PV
system. Cap should not be disturbed or buried waste should not be exposed by
the site clearing equipment.
2. Grading and filling with the top soil to provide a uniform cap depth. Regrading or
transporting additional top soil from off site may be necessary.
3. Compaction of top soil to provide a solid base to support solar array foundations.
For instance, 4 foot soil cap was adequate for the foundation at the Holmes Road
Landfill in Houston, Texas (SRA, 2008).
64
Table 20.Complications and Solutions to the Solar Panels Installation (Sampson, 2009)
Challenge
Steep side
slope
Thin landfill
cap cover
Impact
Storm water
High levels of erosion
High wind loading
Foundation stability for anchoring
solar panels
Maintenance needs of cap
Regrading needs
Puncturing landfill cap
Settlement
Uneven surface due to depressions
Structural stress at settlement areas
Infiltration and water ponding
Foundation integrity
Integrity of gas and leachate piping
Integrity of gas and leachate piping
Integrity of underground utilities
Wind and
snow
loading
System connections
Foundation stability
Routine cap
maintenance
Settlement surveys
Gas extraction activities
Erosion inspections
Vegetation management
Potential Remedy
Flexible PV laminates
Other light weight solar systems
with secure foundations
Re-grading and soil
amendments.
Lightweight, non-invasive
foundations
Ballasted solar platforms and
shallow footings
Fixed tilt mounting structures
Lightweight shallow footings
and ballast
Pre-closure mitigation
Geo-grid reinforcement
Selective placement (i.e., older
waste, construction and
demolition waste)
Use solar panels and mounting
structures with high mechanical
load ratings
Avoid side slope placement
Placement of solar array around
monitoring well heads
Panel height to allow routine
landscaping needs
Existing permanent access roads
Example
Tessman
Road
Landfill,
Pennsauken
Landfill
Fort Carson
Army Base
Pennsauken
Landfill,
Holmes
Road
Landfill
NA
NA
3.3.4 Types of Foundations for Installing Solar Panels
In general, solar panels are fixed to aluminum or steel frames using stanchions
and the frames are supported by concrete foundations by three types of foundation
structures as follows:
1. Ballasted frames
2. Concrete Slab
3. Pre-cast concrete footings.
Of these, concrete slabs are generally heavier than concrete footings and ballasted
frames. They are also subject to cracks due to settlement and may be problematic on
landfills due to settlement and side slope stability concerns. Differential settlement may
be a concern to array piers and footings. Ballast systems are the lightest and preferred for
flat surfaces of landfills. Foundation selection depends on factors such as bearing
capacity of soil, landfill settlement, cap depth, and weight of the PV system. Figures 54,
55 and 56 present different foundations to support PV systems and wind loads with
respect to wind direction.
65
Wind direction
Force (Fw)
Tilt angle
Mounting
structure
Solar Panel
Ɵ
Frame filled with necessary weights
Low Pressure Area
Aggregate bags for resisting wind force
Figure 54. Wind effects on solar panels with ballasted frame foundation.
Force (Fw)
Wind direction
Solar Panel
Tilt angle
Ɵ
High Pressure Area
Mounting structure
ConcreteCC
Slab
Figure 55. Wind effects on solar panels with concrete slab foundation.
Wind direction
Force (Fw)
Tilt angle
Mounting
structure
Ɵ
Solar Panel
Low Pressure Area
Pre-cast concrete footings
Figure 56. Wind effects on solar panels with pre-cast concrete footings.
66
3.3.5 Considerations for Panel Placement
Settlement generally decreases over time as illustrated in Figure 57 (Sampson,
2009). Placement of solar panels on the oldest sections of the landfill where a
considerable settlement has taken place is preferred. This would reduce the
impacts/effects on PV system orientation and foundation due to settlement.
Time
To (closed)
T1
T2
Settlement
Figure 57. Landfill settlement over time.
Areas containing previously compacted old construction debris which does not
undergo major settlement are also suitable for PV systems (Messics, 2009). Some
adjustments for the PV system orientation may be necessary due to the minor settling
may be necessary.
3.3.5.1 Solar Energy System Installation on Flat Surfaces Top surface of the landfill should be able to support the foundation. In general,
flat surfaces are preferred for installing heavy panels (i.e., crystalline cells) to maximize
the energy production and also because of their suitability to support heavy structures in
comparison to surfaces.
3.3.5.2 Solar Energy System Installation on Sloped Surfaces
In the United States, a flat or south facing slope is optimal for solar energy
capture. The solar capture depends on latitudinal location of the site. Placement of panels
on sloped surfaces (especially south facing slopes at higher altitudes), can achieve
maximum solar radiation and benefits the project. However, it is necessary to provide
strong foundation, erosion and storm water control, and minimize shading effects
(Sampson, 2009). Side slopes of 3:1 (i.e., 18 degree slope) are preferred in landfills.
Slopes greater than 5 degrees are affected by erosion effects, shading, and storm water,
hence need to be considered for solar system installation. Engineered retaining walls or
vegetative surfaces can improve slope stability. Additional soil may be required to
improve slope characteristics (Sampson, 2009). Due to slope stability limitations, light
weight panels with strong foundations (i.e., poured or pre-cast concrete footings) are
generally recommended (Sampson, 2009).
67
3.3.6 Wind Load Analyses
3.3.6.1 Wind Load Analysis on Solar Energy Harvesting Systems
Assumptions:
1. Placement of solar panels on landfills using appropriate mounting structures and
foundation is similar to placement of Monoslope Free Roofs over open buildings.
2. Wind loads acting on solar panels are analyzed by considering solar panels as
components and cladding elements.
3. Solar systems are considered as rigid structures with fundamental frequency > 1
Hz (section 6.2 of ASCE 7-05)
4. Solar systems are considered as regular shaped structures with no unusual
geometrical irregularity in spatial form (section 6.2 of ASCE 7-05).
5. Solar systems are considered as non-enclosed structures, defined as temporary
structures used for electricity generation (as per SRA, 2008).
6. Occupancy category is Category-I (i.e., structures causing minimum hazard to
human life in the occurrence of failure) (Table 1-1, page 3 of ASCE 7-05).
7. Solar system considerations
a. Ridge height of the solar system (hr) =6ft
b. Eave height of the solar system (he) =2ft
c. Mean height of the solar system (h) =4ft
8. Evergreen solar panels, model ES-A-200 are considered for the study.
9. Length of the solar panel (l) = 5.42 ft (65 inches)
10. Width of the solar panel (w) = 3.125 ft (37.5 inches)
11. Weight of the solar panel= 42 lbs (19.1 kgs)
Methodology: Wind load analysis on solar panels is determined using the Analytical
Procedure from Chapter 6: Wind Loads of ASCE 7-05- Minimum Design loads for
buildings and other structures.
Parameters Required:
Importance factor (I)
Importance factor is determined from Table 6-1, page 77 of ASCE 7-05 based on
building and structure classification categories listed in Table 1-1, and wind speeds of the
study location.
Directionality factor (Kd)
Directionality factor is determined from Table 6-4, page 80 of ASCE 7-05 based on
structure type and can only be applied when used in conjunction with the load
combinations specified in sections 2.3 and 2.4 of Chapter 2: Combinations of Loads, page
5 of ASCE 7-05.
Wind Speed (V)
68
The basic wind speed corresponding to 3-second gust wind speeds in miles/hour at 33 ft
(10 m) above ground for Exposure Category ‘C’ is obtained from Figure 6-1, page 33 and
Figure 6-1B, page 35 of ASCE 7-05.
Exposure Category
Exposure category of the study area is evaluated in relation to wind direction (from
sections 6.5.6.1, 6.5.6.2, 6.5.6.3, page 25 of ASCE 7-05), ground surface roughness
determined from natural topography, vegetation and existence of constructed facilities.
Velocity pressure exposure coefficient (Kz)
The velocity pressure exposure coefficient for different exposure categories is obtained
from Table 6-3, page 79 of ASCE 7-05 and using the following formula:
Kz = 2.01 [15/zg]2/ α
for z < 15 ft
where,
zg :
α:
Height above local ground level, in feet (meters).
3-sec gust-speed power law exponent (Table 6-2,page 78, ASCE 7-05).
Topographic factor (Kzt)
The topographic factor for the study area is determined from Figure 6-4, page 45 of
ASCE 7-05 and using the following formula:
Kzt = (1 + K1 x K2 x K3)2
where,
K1:
Factor to account for shape of topographic feature and maximum speed-up effect,
determined based on
value.
K2:
Factor to account for reduction in speed-up with distance upwind or downwind of
crest, determined based on
value.
Factor to account for reduction in speed-up with height above local terrain,
K3:
determined based on
value.H: Height of the hill or escarpment relative to
upwind terrain, in feet (meters).
Distance upwind of crest to where the difference in ground elevation is half the
Lh:
height of hill (or) escarpment, in feet (meters).
x:
Distance (upwind or downwind) from the crest to building site in feet (meters).
Velocity Pressure (qz or qh)
Velocity pressure was calculated by the equation provided in Section 6.5.10, page 27 of
ASCE 7-05:
qh =0.00256 x Kz x Kzt x Kd x V x V x I
where,
qh : Velocity pressure evaluated at mean height(h) of the structure.
qz: Velocity pressure evaluated at height ‘z’.
0.00256: coefficient used when there is not sufficient climatic data available.
69
Gust effect factor (G)
Gust effect factor was determined based on type of structure (section 6.5.8, page 26 of
ASCE 7-05).
Net Pressure coefficients (Cn)
Net pressures (contributions from top and bottom surfaces) at different tilt angles
correspond to type of wind flows, effective wind areas and zones (Figure: 6-19A, page 70
of ASCE 7-05).
Net Design Wind Pressure (P)
The net design wind pressure was calculated by the formula provided in Section 6.5.13.3,
page 29 of ASCE 7-05:
P = qh x G x Cn
where,
G:
Gust effect factor.
Cn:
Net pressures (contributions from top and bottom surfaces) of the panel.
Effective Wind Area (A)
The effective wind area of the panels denotes type of zones for evaluation of wind loads.
For values of A ≤ a2 , a2<A≤ 4 a2, A> 4a2 with a= 3ft (minimum), Zone 3, Zone2, Zone1
or combination of the above are chosen for wind load analysis.
A:
Effective wind area, in ft2 (m2).
a:
10% of least horizontal dimension or 0.4h ,whichever is smaller but not less than
4% of least horizontal dimension or 3ft (0.9m).
Wind Force (F)
The wind force acting on panels at different wind speeds was calculated by the following
equation:
F = Pnet x A
where,
F:
Wind force acting on the panel surfaces.
Pnet: Net design wind pressure (sum of external and internal pressures) for calculating
wind loads on buildings or structures, in lbs/ft2 (N/m2).
A:
Effective wind area of the panel surfaces, in ft2 (m2).
3.3.6.2. Wind Load Analyses for Case Study Landfills
Wind load analyses for the case study landfills are provided in Appendix C.
70
TECHNCIAL, ECONOMICAL, ENVIRONMENTAL AND SOCIAL
ASSESMENT
Not all the landfills could be suitable to locate PV systems. This chapter presents
the technical, economical, environmental and social criteria for evaluation of closed
landfills for suitability for use as power parks. The weighted system was used depending
on the importance of each criteria in comparing suitability of alternative sites.
4.1 TECHNICAL ASSESSMENT
The technical analysis was conducted by identifying technical criteria both for
landfill and PV systems and their compatibility to implement a feasible system. Each
criterion was weighed based on their importance for the project implementation with
feasible energy yield. The objective of this process is to assess that the sites are an
intrinsically suitable for a photovoltaic project. Some of the factors were discussed in
sections 3.1.2 and 3.1.3 for preliminary site assessment and screening. In this section
provides a comprehensive analysis after the preliminary site screening. The following
technical factors were identified:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Cap improvement and maintenance
Grid distance
Compatibility
Layout and Arrangement
Rated capacity
Energy generation potential
Integration to the grid
Mitigation of power shortages
Corrosion potential
4.1.1 Cap Improvement and Maintenance
As discussed in section 3.1.3.1, some site work may be necessary to protect the
cap integrity and support the foundation and mounting elements of the PV systems. In
locations where PV systems have been placed on landfills, the site maintenance have
decrease since the vegetative support (i.e., grass) were removed to place the panels. In
general cap improvements consist of the following:
•
•
•
•
Stripping the grass cover and vegetative support
Adding a liner and a high rate filtration layer such as gravel
Installing foundation to mount the PV systems, and
Using anchors to attach the panels.
Materials with high rate infiltration are necessary around the anchors and panels.
Assessment of the cap improvements depend directly on the existing cap conditions.
Two options include: 1. Stripping the vegetation layer and placing the solar panels
directly on the ground, and 2. using short grasses with panels mounted on foundations
71
above the surface. Removing the vegetation was assigned a score of 10 and using short
grasses with mounted panels were as 5.
4.1.2 Grid Distance
Distance to grid is critical deciding whether the system will be stand-alone or
connected to the grid. In some cases number of customers may justify extending the
energy delivery further. However, in most cases connecting to the grid is more
economical than stand-alone projects. The scoring of the grid distance was performed
according to the scale provided in Table 21 in relation to energy needs and line extension
needed.
Table 21. Grid distance criteria valuation
Daily Energy needed
(kWh/Day)
0-3
0-3
3.1-7
3.1-7
7.1-12
7.1-12
12.1-15
12.1-15
15.1-20
15.1-20
>20
Line Extension
needed (km)
0.5
0.6-1.0
1.1-1.5
1.6-2.0
2.1-2.5
2.6-3.0
3.1-3.5
3.6-4.0
4.1-4.5
4.6-5.0
<5.0
Assigned
Value
10
5
10
5
10
5
10
5
10
5
10
4.1.3 Compatibility
Support structures and PV systems should be installed to maximize the
performance. Today solar planes are designed to last in outdoor conditions. However, in
landfill environment there are special maintenance and care needs as described in bellow:
Methane: Methane is not corrosive; however, it could be explosive under certain oxygen
concentration and gas pressure conditions.
Water: Most sites are designed to avoid water infiltration using geotextiles and
impermeable layers. With PV systems, effective runoff control is needed avoid contact
of electrical devices, decrease corrosion and electrical short circuiting.
Settlement: Most PV systems are fixed and landfills in their first stages are undergoing
some settlement while the maturation process. The compatibility between surface
settlement and PV structures is not expected to be a major concern. As the maturation
process changes the surface characteristics, slopes should be monitored to prevent any
alteration of the PV structures. The degree of hierarchy for the compatibility between
72
landfill and PV system is scored based on landfill age after closure and cover makeup and
depth. The scoring was performed as follows:
Years after closure
0-10 years
11-30 years
30-50 years
>50 years
Score
1
3
6
10
4.1.4 Control of Leachate and Gas
There should not be any incompatibility between the existing leachate and gas
collection system and the installed PV system during the construction, operation and
dismantling phases. For site evaluation, a score of 10 was assigned for sites with
monitoring system and gas extraction, and 0 for sites with no or very limited leachate and
gas monitoring. If a site was not closed in an approved and well engineered manner, less
than 5 points were assigned.
4.1.5
Site Maintenance
Level of safety and possible site intrusion potential was taken into account in this
category. Sites with normal to high maintenance activities are scored as 10. A site with
low protection for potential access and intrusion was considered less suitable. In general
those sites with good monitoring programs, slope and settlement control, good cap
conditions and good degree of safety are considered suitable for PV systems and were
scored as 10 for this category.
4.1.6 Surface Water Control
The projects which have been implemented have used underground electrical
wiring through which the current is being transported. To avoid any interference between
water and current, surface water should be managed effectively. Surface should be
inspected periodically and slope erosion and settlement should be corrected. The scoring
was performed as follows:
Surface water control
< 0.01 Meters of drainage/m2
> 0.01 Meter of drainage/ m2
5
10
4.1.7 Infrastructure Needs
Infrastructure needs were discussed in section 3.1.3.12. This section addresses
the evaluation of the necessary infrastructure for different configurations and systems.
Even though flat panels are more efficient, they require more infrastructure set up.
Hence, for this analysis, although flat panels are more efficient, they were scored lower.
The flat panels were scored as 5 and the flexible as 10.
73
4.1.8 Layout and Arrangement
A good rule of thumb for spacing between panels is to assure “enough space
between rows so the shade angle does not greatly exceed the solar altitude angle on
December 21 at noon.” Based on specific site conditions, the angle of the panels have to
be evaluated in relation to the solar altitude to determine the layout. This criterion was
scored based on use of the area for higher energy yield (i.e., number of panels).
4.1.9 Rated Capacity
The amount of energy to be delivered depends on the peak power capacity of the
plant and how much of the capacity is used during the year. When the energy yield is
normalized, it is called the Energy Delivery Factor (EDF). EDF is defined as “the ratio
of the electrical energy delivered to the customers to the energy that can be delivered by
the plant if it could be operated at the fully installed capacity during 8,760 hours of the
year. EDF is represented by the following equation:
Average annual EDF= (KWh delivered/yr) / (Installed capacity x 8760)
(9)
If the maximum capacity of the PV system oriented in a specific direction is Pm , and the
hourly average of the energy delivered through the year is Po , then TMY hourly radiation
average can be estimated as:
Average annual EDF = ∫ Po dt / (Pm x Derate factor x 8760)
(10)
where:
Pm: Plant capacity (the maximum power the plant can deliver) (KWh)
Po : Power delivered to the customers at any time t (KWh).
The derate factor is used to account for the losses during conversion from DC to
AC current (i.e., losses from capture of the solar energy to the net energy production). In
the ideal scenario in which the nameplate capacity of the PV system is the total energy
yield, the total losses based on the NREL estimation are in the order of 33%. This
corresponds to a derate factors 0.77. The EDF depends directly on the energy efficiency,
landfill area and orientation. This factor was scored based on PV technology screening
results. Systems with efficiency of 77% or more were scored as 10 and lower values
were interpolated accordingly. In addition, landfill shape and orientation should be taken
into account.
4.2 ECONOMICAL ASSESSMENT
Several factors influence the economic viability of a proposed plant and its
feasibility. The factors that contribute to the economic feasibility are discussed in this
section. Easy-to-use charts are provided for assessing the feasibility of a planned system.
74
4.2.1 Energy Delivery Factor
The key economic performance of a PV system depends on amount of energy it
produced during the year. For a typical PV system, about 10% of the power is consumed
internally and the remaining is delivered to the customers. The total energy delivered to
the grid depends on the peak power capacity and how that capacity is utilized during the
year. To normalize the energy produced, Energy Delivery Factor (EDF) is defined as:
Average annual EDF= (KWh delivered/yr) / (Installed capacity x 8760)
(11)
Since the load power is changing over the time, the EDF can be expressed as:
Average annual EDF = ∫ Po dt / (Pm x 8760)
(12)
where:
Pm: Plant capacity (the maximum power the plant can deliver).
Po: Power delivered to the customers at any time t.
The EDF can be obtained for a small time interval, then dt can be replaced by Δt. This
parameter is not only useful to estimate the net energy delivery but also to accounts for
the reliability, maintainability, and availability of the plant during the year. Additionally,
EDT is can bed to compare the overall efficiency of the PV plant with other plants.
4.2.2 Initial Capital Cost
The capital cost of a PV system depends on three factors: 1. technology, 2.
operational size, and 3. configuration (i.e., connected to the grid or not). The module cost
represents about 50%-60% of the total cost. The variation in the module retail price in
the last 10 years is presented in Figure 58.
Figure 58. Solar module retail price index (http://www.solarbuzz.com/Moduleprices.htm)
75
4.2.3 Availability and Maintenance
Failure and service interruption could occur at PV plants. During the study, it
was found that 67% of the time when the plant is being repaired, the plan is not
operational. The failure locations are 20% at the electrical power equipment and 19% are
in the electronic controls. The plant availability is defined as number hours the plant is
operating at full capacity divided by the total of hours in the year. This result is reflected
by the energy delivery factor (EDF).
4.2.4 Energy Cost Estimates Economic feasibility of the electrical power plant depends on the unit cost of
energy (UCE) per KWh takes in account all the factors such as availability, maintenance,
initial capital cost and energy delivered. UCE is defined by the following equation:
UCE = [ICC (AMR + TIR) + OMC] / EDF x KW x 8760
(13)
where:
ICC: Initial Capital Cost, including land cost and startup cost up the time the first
unit of energy is sold.
AMR: Amortization rate per year as a fraction of the ICC.
TIR: Tax and insurance rate per year as a fraction of the ICC.
OMC: Operating and maintenance cost per year.
EDF: Energy delivery factor over one year, as defined earlier.
KW: Kilowatt power capacity Installed.
Table 22. Upfront cost for a PV system in the next 10 years (Florida Renewable Energy
Potential Assessment, 2008)
Residential PV Economic Assumptions for
Given Year of Installation (2010)
2010
2015
2020
Plant Nameplate Capacity (kW)1
5
5
5
Project life (years)
25
25
25
Development time (yrs)2
0.3
0.25
0.2
Installed Cot ($kW)3
7,0005
5,9006
4,9007
Fixed O&M ($/kW-yr)4
41
24
13
Non-fuel Variable O$M ($/kWh)
0
0
0
Fuel/energy cost ($/kWh)
0
0
0
1
Data presented in kWDC and kWAC is rated as 0.84 kWDC.
Delays in the state rebate availability is not accounted for.
3
Could vary due to shortage in the feedstock of PV polysilicon, panel efficiency, and streamlines
installation. Prices include hurricane protection.
4
Includes two inverted replacements during the project lifetime.
5
Suretemp PV Solar Company, May 2010.
6
Price is for 2008.
7
Price is for 2008.
2
76
4.2.5 Sensitivity Analysis
Significant variations can occur in energy yield due to radiation fluctuations. A
sensibility analysis was conducted by changing the inputs (i.e., solar radiation) to the
system and determining the output as measured by UCE.
4.2.6 Profitability Index
Florida is among the top 5 states with the highest electricity prices and it is also
among the states with the highest consumption of fossil fuels to produce electricity,
producing more than one half of its energy from gas, oil and coal. Florida’s price of
electricity is above the national average with 11.20 cents per kWh. High prices mean a
good profitability for the new technologies. Even though upfront costs for PV system are
still high, the State and Federal incentives could improve the profitability of renewable
technologies such as wind and solar. Profitability is defined as:
PI = (Present worth of future revenues – Initial cost) / Initial cost
(14)
By definition, breakeven occurs when PI = 0.
4.2.7 Fund for Post Closure Care
During the implementation of PV systems, the landfill post closure objectives
should to be maintained (i.e., protection of human health and ecosystem). Air and water
quality monitoring activities should be conducted to evaluate any potential impacts due to
PV system. The funds allocated for post closure activities may be compensated by the
profits from energy generation. The post closure costs of landfills is about $ 500,000 per
year, and for PV maintenance it is estimated to be about 1% of the upfront cost.
4.3 ENVIRONMENTAL SUITABILITY ANALYSIS
The environmental suitability analysis includes consideration for reduction in
greenhouse emissions, environmental sustainability, visual impacts and the index of
renewable energy system for power production.
4.3.1 Reduction of Greenhouse Emissions
One of the most important aspect of the PV system is the reduction of greenhouse
emissions. In the US, about 59% of the energy is produced from fossil fuels presented in
Figure 59. The renewable energy use is about 7.3%. The wind energy capacity is
currently about 25 GW, and if continues to grow at the current rate, in 33 years it could
reach the nuclear power generation level. Wind energy in the 2009 provided 70.761
thousand megawatt hours of electric power and solar energy provided 808 megawatt
hour. Accordingly to US Department of Energy, the rate of growth of solar energy has
been about 20% per year since 1990. Solar energy will need to be more affordable in
order to attain the emission reduction goals. For each KWh of solar energy installed in
77
the US, and using the Green Power Equivalence Calculator that uses the eGRID
(Emissions & Generation Resource Integrated Information Database) 7.18x10-4 metric
tons of CO2 are avoided. In the case of solar energy for the year 2009, about 5 million
metric tons of CO2 were avoided from being released to the atmosphere.
* Sum of components may not equal 100 percent due to independent rounding.
1
Does not include the fuel ethanol portion of motor gasoline—fuel ethanol is included in
"Renewable Energy."
2
Excludes supplemental gaseous fuels.
3
Includes less than 0.1 quadrillion Btu of coal coke net imports.
4
Conventional hydroelectric power, geothermal, solar/PV, wind, and biomass.
5
Includes industrial combined-heat-and-power (CHP) and electricity-only plants.
6
Includes commercial combined-heat-and-power (CHP) and electricity-only plants.
7
Electricity-only and combined-heat-and-power (CHP) plants whose primary business is to sell
electricity, or electricity and heat, to the public.
Figure 59. US primary energy consumption by source and sector 2008 (U.S. Energy
Information Administration, Annual Energy Review 2008)
4.3.2 Environmental Sustainability
Energy is the power that moves the economy, and economy relies on energy
sources that are mostly nonrenewable. Sustainability is about neither depletion nor
exhaustion of the natural resources with growing economy. From sustainability
perspective, PV system has advantages relative to fossil fuels depletion and the global
warming. Table 23 presents the currently installed capacity of the renewable energy
78
systems in Florida. Table 24 presents the projected renewable energy generation capacity
in the next 10 years.
According to the Florida Energy Portal the net energy generation in 2009 was
about 220,256 GWh. The demand for energy in the State of Florida is anticipated to
increase by 60% by the year 2020to about 352,409 GWh. PV systems could provide a
significant fraction of the demand with an estimated potential of 156,000 GWh. Other
factors such as protection of the environment and the maximization of the natural
nonrenewable resources make solar energy attractive.
Table 23. Existing renewable energy installations (Florida Renewable Energy Potential,
2008)
Source
Generation (MWh)
Solar-PV
2900
Solar-Water Heating
0
Solar-CSP
0
Wind-Onshore
0
Wind-Offshore
0
Biomass-Solid Mass
Municipal Solid
2,848,000
Agricultural byproducts
512,000
Wood/Wood products Industry
1,688,000
Biomass-Landfill Gas
118,000
Biomass-Anaerobic Digester gas
0
Waste heat
2,600,000
Ocean current
0
Hydro
Unknown
TOTAL
7,768,000
Table 24. Projected renewable energy installations (Florida Renewable Energy Potential,
2008)
Source
Technical Potential by 2020
Solar-PV
156,000-173,000
Solar-Water Heating
1,700-2,000
Solar-CSP
600-760
Wind-Onshore
186-293
Wind-Offshore
125,230
Biomass-Solid Mass
29,372- 71,145
Biomass-Landfill gas
740
Biomass-Anaerobic digester gas
245
Waste heat
1,000
Ocean current
156,000-173,000
Hydro
Unknown
TOTAL
547,413
79
4.3.3 Visual Impacts
Visual impact in the PV system includes landscape, architecture, structures, PV
system type and layout. Landfill cover and passive post closure use provide landscape
with grass, trees, and surface water ponds where birds and other animals become part of
the habitat. For solar panel implementation, there are some critical factors to be
considered to protect the natural habitat. PV system layout should maximize the area and
maintain a good landfill shape distribution. Placing the panled directly on soil reduced
the visual impact of tilted panels. Finally, all the cables should be installed underground
and batteries should be located in zones to minimize exposure.
4.3.4 Index of Renewable Energy for Power Production
In the PV-landfill suitability analysis the environmental factors play a key role in
the maximization of the natural resources and these is the most valuable contribution for
the whole project. The valuation of the environmental factors is called the Index of
Renewable Energy for Power production and is defined as the amount of green house
reduction gases per square meter. That number is obtained with the next equation:
I REP = (KWh delivered / year) x Carbon emissions / Project area
(15)
4.4 SOCIAL ASSESSMENT
The social assessment involves the impact of the PV-landfill project in the areas
close to the site where the population may be affected. Social assessment and includes
how the population may benefit from the project. For this a land use assessment is carries
out analyzing the composition of the population. There are some degrees of acceptance or
suitability depending on the type of energy users, the project looks for potential
institutional, public, commercial, industrial, and residential customers in the surrounding
area. In that consideration technology is in some degree well accepted or easily to
penetrate different users in different marketing scenarios. The social assessment is
conducted using GIS tools with metadata of landfill location and land use shape files as
inputs. The results are displayed as maps and the distribution of the population is given
by the spatial analysis of the maps. Technology suitability for customers is evaluated in
terms of energy reliability and availability. More suitable sites are those where
institutional land use is present. The sites near residential and industrial areas are less
desiarble.
4.5 Technical, Economical, Environmental, and Social Assessment Summary
All the factors considered for site suitability are summarized in Table 25. It
should be noted that the results of the evaluations using the criteria developed in Section
4 for the case study landfills are presented in Appendix A and Appendix B.
80
Table 25. Suitability assessment for photovoltaic implementation in closed landfills: technical, economical, environmental and social
factors summary
TECHNICAL
TECHNICAL
FACTOR
Indicator description Description
Dimensions
Indicator
Surrogate values
Cap Improvement
and maintenance
PV system installed on top of the cover
with or without stripping the cover layer
Dimensionless
Yes/Not
Yes = 10
Not = 5
Grid Distance
Total power production and distance to
the grid
KWh for power
km for distance
>20 kWh/day
<5.0 from the grid
Yes=10
Not=5
Years
0-10
11-30
31-50
>50
0-10=1
11-30=3
31-50=6
>50=10
Yes/No
Has the site the set of work to control the
runoff and storm water event (i.e. wet
ponds, ditches, canals)
Yes=10 with design
Yes= 5 without
design
No=0
If 1 is yes = 10
If 1 is not = 5
If 2 is yes=10
If 2 is not =0
Compatibility
Technology and Landfill compatibility
during the construction and operation
phase
Surface Water
Control
Capacity of the landfill to control storm
water events
Control of leachate
and gas
Activities to control and monitor
leachate and gas in two scenarios with
or without gas extraction
Yes/No
1) Existence of monitoring with gas
extraction
2) Existence of monitoring without gas
extraction?
Site maintenance
Monitoring program should be
evaluated on site. Set of activities to
keep the site under safe and quality
conditions
Yes/No
Has the site sets up a program for quality
control (QC) and quality assurance (QA)
plans
Yes=10
No=5
Infrastructural
needs
PV system would need more
infrastructural development base on the
type of the technology to implement
Weight/m2
What the ration of the weight of the PV
infrastructure and the project area?
0-30 kg/m2=10
31-60 kg/m2=5
61-100 kg/m2=3
>100 kg/m2=0
Panel Layout
Number of panel to be located in the
landfill area under development
# of panels/m2
Total panels in the layout area/area
0.47-0.6 = 10
>0.6=5
<0.47=5
Rated Capacity
Is the ratio between the energy delivered
and the total capacity of the plant.
______
Percentage
81
EDF =
kWhyear
Installedc apacity − 8760
77%=8
>77= 10
year
SOCIAL
ENVIRONMENTAL
ECONOMIC
Energy Delivery
factor
Total energy to be delivered at specific
interval of time
∫ P .dt
o.
Percentage
EDF=
77%=8
>77= 10
Pm .8760
<5900$/kW = 10
>5900$/kW,
<7000$/kW = 5
>7000$/kW = 0
Initial capital cost
Amount of money to be invested per
kW installed
Profitability Index
Measures the profitability of a specific
project. Is based on the average solar
radiation per year and the selling price.
Dimensionless
Reduction in
Greenhouse
Emissions
Amount of greenhouse gases that could
be avoided if the project is implemented
Metric tons of
CO2/year
7.18x10 CO2metrictons*KWh/year
>15000 =10
<15000,
>10000 =5
<10000=3
Environmental
Sustainability
Measures the contribution of any
specific project to the total potential of
solar energy in the Florida estimated as
156,000 GW/h
Percentage
(Total power plant capacity/total energy
potential)x100
>5% = 10
<5%,
>2% = 5
<2% = 3
Index of Renewable
energy
Measures the amount of total carbon
emission per kW per year avoided per
square meter in the project area.
Metric tons of
CO2/m2-year
IREP= KWhyearxCa rbonEmissi ons
projectare a
Land Use
Measures the distribution of the land in
the area contiguous to a buffer of 200
meters from to the landfill
Percentage
LU= (Land use/total land)*100
$/Kw
82
$/kW
PI =
futurereve nues − IPC
Initialpro ject cos t ( IPC )
-4
1.0>PI>1.1 = 3
1.1>PI>1.3 = 5
1.3>PI>1.5 = 10
>0.3 = 10
<0.3,
>0.1 = 5
<0.1 = 3
Land use:
Institutional=10
Public=10
Commercial=5
Multifamily=5
Single family = 5
4.5 FUTURE DESIGN CONSIDERATION FOR LANDFILL
According to the assessment the Florida’s closed landfills is a high potential
source for the implementation of PV system. First of all the cost of land is an important
parameter that affects the feasibility of any PV system. Usually available areas are too far
from the grid mostly located in the rural areas. Systems connected to the grid need less
upfront cost due to the low battery dependence. Likewise, if PV technology is getting
mature with time, landfill could follow it up as well trying to design it more compatible
with PV system. Among the results of this research factors such as shape, orientation,
location, area, compatibility, cover, water control, type, and corrosion could in some
improve or impair the PV system performance. Landfill and PV system combination
could be enhanced first in terms of orientation. Site planners and designers should in the
future see carefully the orientation of the cells, and maximize those areas facing south.
For that could be needed to carry out a stability assessment, and see the most suitable
shape without placing a risk in the slopes stability. Likewise, area is a factor that
determines if a project scale makes it either feasible or not, the higher the project scale
and energy demand, the more profitability and as a result the more feasibility is going to
be reached. When we refer us to area is to the effective area no the total area of the
landfill, the area in which solar energy is useful. Well designed landfill would contribute
with about 60%-70% percent of its area rather than the 40%-60% of others designs. The
interaction of the cover of the landfill and the PV system is not well understood yet;
projects like the San Antonio California Landfill are monitoring the cover profile and the
structure and PV system performance. From the experience in the Pennsauken landfill
they used in the construction phase removing of vegetation and create a new cover layer
from which a gravel cover is placed onto the soil as shown in Figure 60. Vegetation
stripping and mountings set up over a gravel layer to allow the runoff free flow.
Figure 60. Cover set up for panel installation (Messic, 2009)
83
Cover in the landfills is not designed to support a PV system, hence changes are expected
in the future in order to complete all the storm water criteria. The runoff effective area of
interception is smaller in the PV system than in the landfill due to the loss of vegetation.
Also retention of the water is not going to occur due to that change and the presence of
the slippery surfaces of the panels, meaning that less detention, less evaporation, and less
transpiration is going to occur, at the end the whole hydrologic cycle in the landfill is
changed, and the attenuation process of the storm events will decrease. A new hydrologic
cycle is proposed when PV system is placed on the landfill, to compensate the attenuation
reduction high rate drainage system with higher capacity has to be designed in the future
landfill, retention time of runoff is going to decrease and peak flows increase with less
time of concentration, as a result high capacity drainage system to control short storm
events has to be designed, tested, monitored, and reported. In conclusion this topic is still
under development in almost all the landfills where PV system has been implemented.
4.6 COST AND BENEFITS OF USING FLORIDA’S CLOSED LANDFILLS AS
POWER PARKS
Solar photovoltaic (SPV) power plants have long operational lives with zero fuel cost and
small maintenance costs. However, the cost of initial investment is very high (Singh and
Singh, 2010).
4.6.1 Cost of Solar Panels
Solar panel considered for this project is ES A 205 module. The specification opf the
panels are as fllows:
Peak Power (Watts)
205
Peak Power Voltage (Volts)
18.4
Peak Power Current (Amps)
11.15
4.6.2 Dimensions
The solar panel dimensions are given in Table 26.
Table 26. Solar panel dimensions
Dimensions
inch
ft
m
Length
65.00
5.42
1.65
Width
37.50
3.12
0.95
Depth
1.80
0.15
0.046
To produce 1 KW, 5 panels are required (i.e., 1 panel produces 205 watts). Hence, 5000
panels would ne required to produce 1 MW (i.e., 1MW = 1000 KW)
4.6.3 Weight
Each panel weighs about 42 lbs. The total weight would be 5000x42= 210,000 lbs.
84
4.6.4 Cost of Panels
Cost of each panel is $1,373. To produce 1KW would cost 1373x5 = $ 6,865 as shown in
Figure 61.
Cost of panels to produce 1 MW:
5000x $1,373= $ 6.865 Million
Initial Investment:
Assuming 0.5 MW is produced for the best scenario in 1 hr from a 1MW facility:
Power produced on one day:
0.5 MW x 24 hrs = 12 MW
Power produced in one month:
12 MW x 30 days = 360 MW
Power produced in one year:
360 MW x 12 months = 4,320 MW
Assuming 0.25 MW is produced in worst case scenario for 1 hr from 1MW facility:
Power produced on one day:
0.25 MW x 24 hrs = 6 MW
Power produced in one month:
6 MW x 30 days =180 MW
Power produced in one year:
180MW x 12 months=2,160 MW
Formulae for substituting Initial Investment for Solar Power Plant:
Es = Eu / Rc
where,
Es :
specific electric output of SPV panel at a given place (kWh/ kWp-year)
Eu : units of electricity generated per year at a given place (kWh/year)
Rc :
rated capacity of the SPV system (KWp)
For good scenario (Singh and Singh, 2010):
Eu = 4,320,000 KWh/yr
Rc = 500 KWp
Then:
85
Es = 4,320,000 / 500 = 8,640
Specific electric output of SPV panel is 8,640 kWh/ KWp-year
KW vs Price
Price dollar
1000000
800000
600000
400000
200000
0
0
50
100
150
KW
Figure 61. Price of panels per KW
4.6.5 Labor Cost
Assuming 40 people work at the solar power plant with hourly rate of $17 per hour.
Then, personnel cost is about $700 /hr.
Considering 8 hour work day, each day $ 5,600 and for month is $0.168 Million and for
year $2.016 Million for 40 workers.
Assuming engineering cost of $ 50,000; site development cost is $45,000; and
miscellaneous expenses are $ 0.7Million; then overall solar power plant cost would be
$16.976 Million (Rehman et al., 2007)
Table 27. Solar power system costs
Item
Development (apprx)
Engineering (apprx)
Initial (apprx)
Operation (apprx)
Miscellaneous (apprx)
Cost of solar panels
Labor cost
TOTAL
Cost
$ 45,000
$ 50,000
$ 7,000,000
$ 300,000
$ 700,000
$ 6,865,000
$ 2,016,000/year
$ 16,976,000
86
5. CONCLUSIONS
A comprehensive analysis was conducted to evaluate the suitability of closed
landfills to be used as power parks in Florida. Wind load, slope factor, panel weight,
foundation considerations, landfill settlement, control of leachate and gas, shading
effects, economic, environmental and social aspects were considered. Technical and
economic factors considered included efficiency of solar energy harvesting systems,
landfill characteristics, suitable landfill areas of maximum solar availability, proximity of
utility grid system, preparation of landfill cap to support foundations (if needed), landfill
cap maintenance (vegetation growth), panel maintenance, structural and infrastructural
needs, auxiliary equipment, and public acceptance were also considered.
A total of 18 criteria were identified and evaluated for the suitability analysis (10
technical criteria, 4 economical criteria, 3 environmental criteria, and 1 social criterion).
A total of 180 points was assigned for an ideal site. Due to the large number of sites in
Florida, selected technical criteria were used to screen the sites prior to detailed analyses.
Orientation, topographic, operational status, and cover/cap makeup were considered for
preliminary screening. Two landfills in the South Florida were identified as case study
sites for further evaluation. In depth analyses were conducted using technical,
economical, environmental, and social criteri. An empirical model was developed to
estimate solar radiation and energy yield at each site.
After the suitability assessment, the NW 58th street landfill received 130.4 points
and the North-Dade landfill received 127.4 points out of 180 points for an ideal site. At
the 58th street landfill the solar energy generation potential was estimated as 38.33 MW/h
and the delivery of energy was estimated as 20.64 MW/h. At the North-Dade landfill the
solar energy generation potential was estimated as 58.50 MW/h and the delivery energy
was estimated as 31.37 MW/h. Based on the Florida Governor’s Energy Office, solar
energy potential for Florida in the year 2020 is 156,000 GWh and currently installed
capacity is about 2,900 MWh. There is a significant potential for the solar energy
generation in Florida. The results of this research provides guide for using closed landfills
as power parks.
The unit cost of energy for a gridded PV system (no batteries) on a closed landfill
in an urban area was estimated as $ 0.100 US/kW. This is close to the average cost of
energy in Florida ($0.112 US$/kW in 2007). Event tough these estimates are favorable
for solar energy systems, there are other concerns such as reliability and load equalization
for providing the energy to the customers directly.
One of the findings in this research is that storm water flow can change by the PV
layout. Therefore, is necessary to reassess the storm water managment after the
placement of the solar panels. Based on the research and empirical model results, the best
orientation for the photovoltaic systems is between 10 and 40 degrees facing south.
Therefore, slopes between 0.2 m/m and 0.8 m/m would be optimum for the PV systems.
When compared with typical landfill slope of 0.33 m/m, it could be concluded that
landfills side slopes are within the range of maximum efficiency. Because of slope
87
variations and small variations in energy yield between with slope; it is reasonable to
consider a PV system which does not include support structure for placing PV panels at
specific angles on the ground supports. Tilted panels could be considered on the flat areas
to increase energy yield.
Wind load analysis on solar panels for North Dade Landfill and North West 58th
Street Landfill were conducted as case studies. The design wind speeds for Miami Dade
County is between 140-150 mph, with the average design wind speed of 146 mph (FBC,
2008). Analyses were performed for wind speeds of 120-150 mph. Evergreen solar
panels of ES-A-200 were used for analysis and Analytical Procedure from Chapter 6:
Wind Loads of ASCE 7-05 was used as the methodology to evaluate the wind loads
(Minimum Design Loads for Building and Other Structures). At the North Dade Landfill
For panels placed on flat and south facing sloped surfaces, the estimated wind pressures
were 46.40 lbs/sq ft and 38.36 lbs/sq ft, respectively. At the North West 58th Street
Landfill, the estimated wind pressures were 58.02 lbs/sq ft and 44.17 lbs/sq ft and wind
forces corresponding to panels placed on flat and south facing sloped surfaces. Florida
being a hurricane-prone region, there is possibility of higher wind loads. Hence, wind
loads should also be considered with appropriate supporting structures and safety factors.
Wind tunnel experiments can provide necessary design data for solar installations for
design purposes. The overall suitability assessment scores were 130.4 point for the 58th
street landfill and 127.4 points for the North-Dade landfill 127.4 out of 180 total points
(ideal site).
This study provides a guideline for establishing criteria to implement PV system
on closed landfills in Florida to generate electricity and promote sustainable resources for
energy generation.
88
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93
7. APPENDICES
94
Appendix A – Implementation of PC System at 58th Street Landfill
Table A-1. Assessment of PV system at the 58th Street Landfill in Miami Dade County
TECHNICAL
CRITERIA
FACTOR
Description
Dimensions
Scoring criteria
Cap Improvement
and maintenance
A new cover layer is proposed.
Stripping vegetation is applied to the
currently cover avoiding the
landfill’s liner damage.
Dimensionless
Proposed to install new cover layers.
0-10
Grid Distance
Expected to generate more than 20
kWh and the grid distance is less
than 5 km. both are in the urban area.
Kwh for power
km for distance
Compatibility
Technology and Landfill
compatibility during the construction
and operation phase
Surface Water
Control
Capacity of the landfill to control
storm water events
Control of
leachate and gas
Activities to control and monitor
leachate and gas in two scenarios
with or without gas extraction
>20 kWh/day
<5.0 km from the grid
58th Street
Landfill
S
l
10
10
0-10
11-30
31-50
>50
6
Yes/No
Have runoff control (i.e. wet ponds, ditches,
canals)
8
Yes/No
1) Existence of monitoring with gas extraction
Yes
2) Existence of monitoring without gas
extraction? 58th street landfill does not extract
gases.
8
Years
95
Site maintenance
Monitoring program should be
evaluated on site. Set of activities to
keep the site under safe and quality
conditions
Infrastructural
needs
Evergreen solar panels weight is 18.6
kg plus supports weight depending
on the wind load.
Yes/No
Wieight/m2
Has the site set up for quality control (QC) and
quality assurance (QA) plans.
Yes but not evidence
Not heavy structures expected on the top and
slope site of the landfill
5
10
2
30 kg/m =10
Total panel in the layout area/area (m2)
58th Streeth ladnfill = 0.18
Panel Layout
See tables A-2 and A-2. Figure A-1
# of panels/m2
Rated Capacity
The ratio between the energy
delivered and the total capacity of the
plant. (See table A-4 and Figure A-2)
Percentage
Energy Efficiency
The ratio between the energy yield
and the installed capacity (Table A3)
Percentage
Energy Delivery
factor
Total energy to be delivered at
specific interval of time. (See Table
A-3 and Figure A-1)
0.3-0.6 = 10
>0.6=5
<0.47=5
______
EDF =
kWhyear
Installedcapacityx8760
EEF=
Energyyield
Installedcapacity
5
8*
7.1
year
∫ P .dt
o.
Percentage
EDF=
96
Pm .8760
5.3
ECONOMIC
ENVIRONMENTAL
Initial capital cost.
Funds to be invested per kW installed
(Table A-5)
Energy Cost
estimates
Principal decision-making parameter
(UCE) cost to pay by the customers
for the service (Table A-6)
Profitability
Index.
$/Kw
900$/kW = 10
>5900-7000 $/kW= 5
>7000$/kW = 0
5
$/kW
>0.15$/kW = 1
0.12-0.15$/kW = 3
0.10-0.122 $/kW = 5
<0.10 $/kW =10
10
Measures the profitability of a
specific project. Is base on the
average solar radiation per year and
the selling price (Table A-6)
Dimensionless
.0>PI>1.1 = 3
1.1>PI>1.3 = 5
1.3>PI>1.5 = 10
5
Reduction in
Greenhouse
Emissions.
Amount of greenhouse gases that
could be avoided if the project is
implemented (Table A-7)
Metric tons of
CO2/year
Environmental
Sustainability.
Measures the contribution of any
specific project to the total potential
of solar energy in the Florida
estimated as 156,000 GW/h (Table
A-7)
Percentage
97
>100,000 =10
>50,000-100,000 =5
<50,000=3
>5% = 10
>2-5% = 5
<2% = 3
10
3
SOCIAL
Index of
Renewable
energy.
Land Use.
Measures the amount of total carbon
emission per kW per year avoided
per square meter in the project area
(Table A-7)
Measures the distribution of the land
in the area contiguous to a buffer of
2000 meters from the landfill
boundaries (A-2)
Metric tons of
CO2/m2-year
>0.3 = 10
0.1-0.3= 5
<0.1 = 3
10
Percentage
Predominance of land use:
Institutional=10
Public=10
Commercial=5
Multifamily=5
Single family = 5
Industrial = 5
5
98
A.1 Panel layout 58th street Dade landfill
-
Six cells of 21 each one
Total area 1,050,000 m2
Area available 388,500 m2
Standard 0.77 panel/ m2 (2 m2/panel)
194,150 panels
Table A-2. Layout distribution in the 58th Dade landfill.
Cell number
Sheet 5
Sheet 7
Sheet 8
Sheet 9
Sheet 6
Sheet 4
Total area available
Placement area
(0.25x21)
(0.65x21)
(0.7x21)
(0.25x21)
wetland
Debris zone
Area
available
(has)
5.25
13.65
14.7
5.25
--38.85
Area per orientation (has)
South
Flat
East
West
0
0
0
1.31
5.25
13.65
7.35
1.31
0
0
3.68
1.31
0
0
3.68
1.31
1.31
27.56
4.99
4.99
Figure A.1. 58th Landfill topography
99
A.2. Energy delivery factor
South
Sheet 5
Sheet 7
Sheet 8
Sheet 9
Total area per
orientation
Total panels
0
1.31
Table A-3. Area distribution
Area per orientation (has)
Flat
East
5.25
13.65
7.35
3.67
1.31
1.31
Area per cell (has)
West
3.67
1.31
5,25
13,65
14,7
5,25
1.31
27.56
4.98
4.98
38.85
6,550
137,800
24,900
24,900
194,150
TOTAL
Installed
capacity MW/h
Delivery energy
Energy
conversion
efficiency (%)
Area
distribution (%)
Overall
efficiency and
area relation
(Eff/m2)
1.31 MW/h
27.56 MW/h
4.98 MW/h
4.98 MW/h
38.83 MW/h
1.11 MW/h
14.58 MW/h
2.21 MW/h
2.73 MW/h
20.64 MW/h
84.80
52.91
44.45
54.76
3.37
70.9
12.82
12.82
100%
1.88
37.55
5.70
7.02
53.14%
Table A-4. Energy yield from the empirical model per orientation
Orientation
surface
TMY hourly Radiation
average (w/h-m2)
Average Hours per
year (hr)
Area
(m2)
Energy yield
per MW/h
East
West
South
North
Flat
214.5089198
229.3012464
321.9539671
217.00235
200.8938118
3631
4184
4615
3343
4615
49800
49800
13100
0
275600
2.21
2.73
1.11
0.00
14.58
100
Energy Delivery Factor
0.9
0.8
0.7
0.6
EDF
0.5
Log.
0.4
0.3
0.2
0.1
0
1/0/00
2/19/00
4/9/00
5/29/00
7/18/00
9/6/00
10/26/00
12/15/00
Date
Figure A-2. 58th Street Landfill
Energy yield per orientation MW/h
16.00
14.00
12.00
10.00
MW/h
8.00
6.00
4.00
2.00
0.00
Eas t
Wes t
South
Orientation
North
Flat
Energy yield per MWh
Figure A-3. Energy yield 58th street landfill run under empirical model conditions and orientation
101
Energy yield per orientation W/h
90.00
80.00
70.00
60.00
50.00
W/h
40.00
30.00
20.00
10.00
0.00
East
West
South
Orientation
North
Flat
Energy yield per MWh
Figure A-4. Average Energy yield 58th street landfill run in empirical model conditions and orientation
102
A.3 Energy Cost estimates and profitability
Table A-5. Energy cost estimates
Economic
$/kw installed for flat
$7,000.00
$/kw installed for flexible
$4,500.00
Initial capital cost (ICC)
$271,810,000.00
Amortization rate AMR (7.5%)
$20,385,750.00
Tax and insurance rate (1% ) (TIR)
$2,718,100.00
Operate and maintenance cost OMC (1%)
$2,718,100.00
Energy delivery factor (EDF)
0.77
Installed capacity (MW/h)
38.83
UEC
$0.10
Table A-6. Profitability
Index Profitability Index
Initial Investment
Cash flow from investment
Number of time periods (years)
Opportunity cost (5%/ tiem period)
Final value of the investment
Present value of cash flows
Net present value of money
Profitability Index:
Benefit to cost ratio
$ 271,810,000
$ 33,535,000
20
5%
$ 100,000,000
$ 350,706,394
$ 78,896,394
1.29
A.4 Environmental
Table A-7. Environmental sustainability
Reduction in greenhouse emissions CO2
(metric tons per year)
127,415
Environmental Sustainability %
0.0000249
Index of renewable energy (metric-ton-m2)
0.328134242
103
A.5 Social
Figure A-4. Land use
104
Appendix B – Implementation of PC System at North-Dade landfill in the Miami Dade County
TECHNICAL
CRITERIA
Table B-1. Assessment of PV system at the at North-Dade landfill in the Miami Dade County
Description
North-Dade
FACTOR
Dimensions
Scoring criteria
Landfill
Cap
Improvement
and
maintenance
A new cover layer as showed in figure
14 is proposed. Stripping vegetation is
applied to the currently cover avoiding
the landfill’s liner damage.
Dimensionless
Grid Distance
In both sites is going to be expected to
generate more than 20 kWh and the grid
distance is less than 5 km. both are in
the urban area.
Kwh for power
km for distance
Compatibility
Technology and Landfill compatibility
during the construction and operation
phase
Surface Water
Control
Capacity of the landfill to control storm
water events
Control of
leachate and
gas
Activities to control and monitor
leachate and gas in two scenarios with
or without gas extraction
Proposed to install new cover layers.
0-10
>20 kWh/day
<5.0 km from the grid
10
10
0-10
11-30
31-50
>50
3
Yes/No
Runoff control structures exists (i.e. wet
ponds, ditches, canals)
8
Yes/No
1) Existence of monitoring with gas
extraction Yes
2) Existence of monitoring without gas
extraction
10
Years
105
Site
maintenance
Monitoring program should be
evaluated on site. Set of activities to
keep the site under safe and quality
conditions
Infrastructural
needs
Evergreen solar panels weight (18.6
kg/panel) plus support weight
depending on the wind load.
Yes/No
Weight/m2
Has the site set up for quality control (QC)
and quality assurance (QA) plans.
Yes but not evidence
No heavy structures are expected on the
top and side slopes
5
10
2
30 kg/m =10
Total panel in the layout area/area (m2)
North Dade Landfill: 0.46
# of panels/m2
Panel Layout
See table B-2
Rated Capacity
The ratio between the energy delivered
and the total capacity of the plant.
(Table B-3 and Figure B-2)
Percentage
Energy
Efficiency
Ratio between the energy yield and the
installed capacity( Table B-4)
Percentage
Energy
Delivery factor
Total energy to be delivered at specific
interval of time (Table B-4 and Figure
B-1)
10
0.3-0.6 = 10
>0.6=5
<0.3=5
______
kWhyear
Installedcapacityx8760
8*
Energyyield
=52.01%
Installedcapacity
5.2
EDF =
EEF=
year
∫ P .dt
o.
Percentage
EDF=
106
Pm .8760
5.2
=52%
ENVIRONMENTAL
ECONOMIC
Initial capital
cost
Funds to be invested per kW installed
(Table B-5)
Energy Cost
estimates
Principal decision-making parameter
(UCE) cost to pay by the customers for
the service (Table B-5)
Profitability
Index
$/Kw
900$/kW = 10
>5900-7000 $/kW= 5
>7000$/kW = 0
0
$/kW
>0.15$/kW = 1
0.12-0.15$/kW = 3
0.10-0.122 $/kW = 5
<0.10 $/kW =10
5
Profitability of a specific project based
on the average solar radiation per year
and the selling price (Table B-6)
Dimensionless
.0>PI>1.1 = 3
1.1>PI>1.3 = 5
1.3>PI>1.5 = 10
10
Reduction in
Greenhouse
Emissions
Amount of greenhouse gases that could
be avoided if the project is implemented
(Table B-)
Metric tons of
CO2/year
Environmental
Sustainability
Measures the contribution of any
specific project to the total potential of
solar energy in the Florida estimated as
156,000 GW/h (Table B-7)
Percentage
107
>100,000 =10
>50,000-100,000 =5
<50,000=3
>5% = 10
>2-5% = 5
<2% = 3
10
3
Index of
Renewable
energy
Measures the amount of total carbon
emission per kW per year avoided per
square meter in the project area (Table
B-7)
Metric tons of
CO2/m2-year
>0.3 = 10
0.1-0.3= 5
<0.1 = 3
10
Percentage
Predominance of land use:
Institutional=10
Public=10
Commercial=5
Multifamily=5
Single family = 5
Industrial = 5
5
SOCIAL
Land Use
Measures the distribution of the land in
the area contiguous to a buffer of 2000
meters from to the landfill (Figure B-2)
108
B.1 Panel Layout North Dade landfill
-
Seven cells of 21 each one
Total area 630,000 m2
Area available 585,000 m2
Standard 0.77 panel/ m2 (2 m2/panel)
253,300 panels
Cell number
Sheet 2
Sheet 3
Sheet 4
Sheet 5
Sheet 6
Sheet 7
Total area available
Table B-2. Layout distribution in the North Dade Landfill
Area
Area per orientation (has)
Placement area
available
South
Flat
East
(has)
(0.70x30)
(0.65x30)
(0.4x30)
(0.38x30)
Active Cell
Active zone
21
19.5
13.5
11.4
--65.4
0
5.265
0
2.85
12.6
9.75
10.8
8.55
0
0
0
0
4.2
4.485
0
0
8.115
41.7
0
8.685
Figure B-1. North-Dade Landfill topography
109
West
B.2. Energy delivery factor
South
0
5.265
0
2.85
Sheet 2
Sheet 3
Sheet 4
Sheet 5
Total area per
orientation
Total panels
Table B-3. Area distribution
Area per orientation (has)
Flat
East
12.6
0
9.75
0
10.8
0
8.55
0
Area per cell (has)
West
4.2
4.485
0
0
16.8
19.5
10.8
11.4
8.115
41.7
0
8.685
58.5
40,575
208,500
0
43,225
292,300
TOTAL
Installed
capacity MW/h
8.115 MW/h
41.7 MW/h
0 MW/h
8.685 MW/h
58.5 MW/h
Delivery energy
4.54 MW/h
22.07
MW/h
0 MW/h
4.76 MW/h
31.37 MW/h
55.9
52.9
0
54.8
13.9
71.3
0
14.8
100%
7.75
37.72
0
8.13
53.61%
Energy
conversion
efficiency (%)
Area
distribution (%)
Overall
efficiency and
area relation
(Eff/m2)
Table B-4. Energy yield from the empirical model with orientation
Orientation
surface
TMY hourly Radiation
average (w/h-m2)
Average Hours per
year (hr)
Area
(m2)
Energy yield
per MW/h
East
West
South
North
Flat
214.50
229.34
212.34
175.75
200.89
3631
4184
4615
4572
4615
49800
49800
13100
0
275600
0.00
4.76
4.54
0.00
22.07
110
Energy Delivery Factor
0.9
0.8
0.7
0.6
EDF
0.5
Log.
0.4
0.3
0.2
0.1
0
1/0/00
2/19/00
4/9/00
5/29/00
7/18/00
9/6/00
10/26/00
12/15/00
Date
Figure B-2. Energy delivery factor at North Dade Landfill
Energy yield per orientation MW/h
25.00
20.00
15.00
MW/h
10.00
5.00
0.00
Eas t
Wes t
South
Orientation
North
Flat
Energy yield per MWh
Figure B-3. Energy yield North Dade landfill run under empirical model conditions and per orientation
111
B.3 Energy Cost estimates and profitability
Table B-5. Energy cost estimates
Economic
$/kw installed for flat
$/kw installed for flexible
Initial capital cost (ICC)
Amortization rate AMR (7.5%)
Tax and insurance rate (1% ) (TIR)
Operate and maintenance cost
OMC (1%)
Energy delivery factor (EDF)
Installed capacity (MW/h)
$ 7,000.00
$ 4,500.00
$ 409,500,000.00
$ 30,712,500.00
$ 4,095,000.00
$ 4,095,000.00
0.77
$ 58.50
Unit Cost of Energy UEC
(kW/h)- Flap panels
$ 0.10
Table B-6. Profitability
Profitability Index
Initial Investment
Cash flow from investment
Number of time periods
Opportunity cost (5%/ time period)
Final value of the investment
Present value of cash flows
Net present value of money
Profitability Index Benefit
cost ratio
409,500,000
50,522,727
20
5%
50,000,000
648,469,325
238,969,325
1.58
B.4 Environmental
Table B-7. Environmental sustainability
Reduction in greenhouse emissions CO2
(metric tons per year)
Environmental Sustainability %
Index of renewable energy (metric-ton-m2)
112
197,261
0.0000375
0.3371
B.5 Social
Figure B-4. Land use
113
APPENDIX C. Wind Load Analyses
Case Study 1: North Dade Landfill
Study Area: North Dade Landfill
Location:
21500 NW 47th avenue, Opa-locka, Miami Dade County, FL 33055
shown in Figure 58.
Latitude: 25.97, Longitude: -80.29
Figure C.1. Satellite image of North Dade Landfill
Assumptions:
1. Closed side of the landfill (left in Figure 58) is considered for wind load
analysis.
2. Elevation contours for the closed side of the landfill range from 10 ft to 80 ft
with 87.9 being the highest elevation (from Auto CAD drawings provided by
Solid Waste Department, Miami Dade County). Assuming the landfill is
leveled using appropriate soil to an elevation of 90 ft, suitable for solar
systems installation, the height of the hill or escarpment (landfill) relative to
upwind terrain is taken as 90 ft for wind load analysis.
3. Distance (upwind or downwind) from the crest to the building or structure site
(x) is 30 ft.
4. Distance upwind of crest to where the difference in ground elevation is half
the height of hill or escarpment (landfill) is measured as 306.69 feet.
5. For slope surface scenario, topographic factor (Kzt) is taken as the average of
the flat (top) surface of the landfill and ground surface.
6. Eave height and ridge height of the solar system are 2 ft and 6 ft, respectively.
7. Wind Pressure (qh or qz) for the structure is analyzed at z= mean height of the
structure (h) = 4 ft.
114
8. Effective wind area of the panels corresponding to appropriate zones at
different tilt angles and type of wind flows were for the following cases: 1
panel corresponding to zone 3; 4 panels corresponding to zone 3 and zone 2;
16 panels corresponding to zone 3, zone 2 and zone 1.
Design Inputs and Calculations:
Wind speed (V): Range of wind speeds for the study area is between 140 mph -150 mph
as shown in Figure 59 (wind speed contours, wind speed map of Figure: 6-1, page 33
and Figure: 6-1B, page 35 of ASCE 7-05; wind speed map of counties by FBC, 2008,
Google map resources). The corresponding design wind speed for Miami Dade County is
146 mph as per FBC 3-second gust speed at 33ft(10m) above ground corresponding to
Exposure category “C”(FBC, 2008). This value was used for the wind load analysis
along with different wind speeds ranging from 120 mph to 150 mph. These wind speeds
correspond to 3-second gust in mph at 33 ft (10 m) above ground for Exposure Category
“C.”
Figure C.2. Wind Speed contour map for Miami Dade County (Google map resources)
Importance factor (I): Importance factor was assumed as 0.77 based on wind speed
velocity and the solar systems were considered as category I (Table 6-1 of ASCE 7-05).
Directionality factor (Kd): Directionality factor was assumed as 0.85 for the solar
systems considered corresponding to solid sign category (Table 6-4 of ASCE 7-05).
115
Velocity pressure exposure coefficient (Kz)
Kz = 2.01 [15/zg]2/ α
for z < 15 ft
where,
z:
Height above local ground level taken at mean height of system = 4 feet.
Nominal height of the atmospheric boundary layer was assumed as 900 ft for
zg:
Exposure “C” (Table 6-2 of ASCE 7-05)
α:
3-sec gust speed power law exponent was assumed as 9.5 for Exposure “C”
(Table 6-2 of ASCE 7-05)
Then:
Kz = 2.01 [15/900]2/ 9.5 = 0.85
Topographic factor (Kzt) for Flat (Top) surfaces of Landfill
Kzt = (1 + K1 x K2 x K3)2
K1 evaluated by interpolating H/Lh value (as per Fig. 6-4, page 45 of ASCE 7-05)
K2 evaluated by interpolating x/Lh value (as per Fig. 6-4, page 45 of ASCE 7-05)
K3 evaluated by interpolating z/Lh = h/Lh value (as per Fig. 6-4, page 45 of ASCE 7-05)
where,
h:
Height above local ground level taken at mean height of system = 4 feet
H:
Height of the hill or escarpment = 90 ft (assuming uniform ground level attained
on the landfill after leveling, suitable for solar systems installation).
Distance upwind of crest to where the difference in ground elevation is half of the
Lh:
height of the hill or escarpment = 306.69 ft (from the AutoCAD drawings of the
landfill, provided by Solid Waste Department, Miami Dade County).
x:
Distance (upward or downwind) from the crest to the building site= 30 ft
(assumed in Auto CAD drawings of the landfill, provided by Solid Waste
Department, Miami Dade County).
H/Lh = 90 / 306.69 = 0.29
Hence, K1 after interpolation= 0.25 (Fig. 6-4, page 45 of ASCE 7-05)
x/Lh = 30 / 306.69 = 0.098
Hence, K2 after interpolation= 0.976 (Fig. 6-4, page 45 of ASCE 7-05)
z/Lh = 4 / 306.69 = 0.013
Hence, K3 after interpolation= 0.971 (Fig. 6-4, page 45 of ASCE 7-05)
Kzt = (1+0.25 x 0.976 x 0.971)2 = 1.53
Topographic factor (Kzt) for Sloped surfaces of Landfill
Topographic factor (Kzt) for horizontal ground surface= 1
116
Topographic factor (Kzt) for Flat (Top) surfaces of Landfill, calculated = 1.53
Topographic factor (Kzt) for Sloped surfaces of Landfill = average Kzt of flat and
horizontal ground surface = (1.53 + 1)/2 = 1.27.
Velocity Pressure (qh) for Flat (Top) surfaces of Landfill
qh =0.00256 x Kz x Kzt x Kd x V x V x I
qh =0.00256 x 0.85 x 1.53 x 0.85x 146 x 146 x 0.77 = 46 lbs/sq ft
Velocity Pressure (qh) for Sloped surfaces of Landfill
qh =0.00256 x Kz x Kzt x Kd x V x V x I
qh =0.00256 x 0.85 x 1.27 x 0.85 x 146 x 146 x 0.77 = 38 lbs/sq ft
Gust effect factor (G) : Gust effect factor (G) was assumed as 0.85 for solar systems as
rigid structures (Sections 6.2, page 21 and 6.5.8, page 26 of ASCE 7-05).
Angle of Panels Placement or Tilt Angle (θ): Angle of panel placement or tilt angle
corresponds to angle of plane of the panel from horizontal, measured in degrees. For tilt
angles ranging from 0° to 30º and wind load analysis for solar panels is analyzed with
respect to wind flow, wind direction and corresponding zones.
Wind directions: Wind forces on the solar systems acting in the directions of D=0º and
D=180° are considered.
Wind flows: Clear wind flow= relatively unobstructed wind flow with blockage <50%
Obstructed wind flow= Objects below roof inhibiting wind flow with blockage >50%.
Sign Convention: Positive forces correspond to wind pressures acting towards the
panel’s surface. Negative forces correspond to wind pressures acting away from the
panel’s surface.
Net pressure coefficients (Cn) Cn=Net pressures (contributions from top and bottom
surfaces) at different tilt angles correspond to type of wind flows, effective wind areas
and zones (as per figure: 6-19A, page 70 of ASCE 7-05).
Net Design Wind Pressure (P): The net design wind pressure is calculated using
formula as per section 6.5.13.3, page 29 of ASCE 7-05.
where,
P = qh x g x Cn
G:
Cn:
Gust effect factor.
Net pressures (contributions from top and bottom surfaces) of the panel.
117
Effective Wind Area (A): The effective wind area of the panels denotes type of zones
for evaluation of wind loads. For values of A ≤ a2 , a2<A≤ 4 a2, and A> 4a2 with a= 3ft
(minimum), Zone 3, Zone 2, Zone1 or combination of the above were chosen for wind
load analysis. The analyses were conducted for 1 panel corresponding to Zone 3; 4 panels
corresponding to Zone 3 and Zone 2; 16 panels corresponding to Zone 3, Zone 2 and
zone 1.
A:
a:
Effective wind area, in ft2 (m2).
10% of least horizontal dimension or 0.4h ,whichever is smaller but not
less than 4% of least horizontal dimension or 3ft (0.9m).
Wind Force (F) The wind force acting on the panels with respect to different wind
speeds is calculated using the formula below.
where,
F = Pnet x A
F:
Pnet:
A:
Wind force acting on the panel surfaces, in lbs.
Net design wind pressure (sum of external and internal pressures) for
calculating wind loads on buildings or structures, in lbs/ft2 (N/m2).
Effective wind area of the panel surfaces, in ft2 (m2).
Wind load analysis for flat surfaces and sloped surfaces at the North Dade Landfill are
provided in Appendix C1 and Appendix C2, respectively.
118
Case Study-2: North West 58th Street Landfill
Study Area: North West 58th Street Landfill
Location: 6990 NW 97th Ave, Miami, Florida 33178 shown in Figure 60.
Latitude: Latitude: 25.84, Longitude:-80.36.
Figure C.3. Satellite image of North West 58th Street Landfill
Assumptions:
1. Closed landfill section (left hand side) is considered for wind load analysis.
2. Elevation contours for the closed side of the landfill are ranging from 10 ft to 80 ft
with 85.6 being the highest elevation (as per Auto CAD drawing, provided by
Solid Waste Department, Miami Dade County). Assuming the landfill is leveled
using appropriate soil to an elevation of 88 ft, suitable for solar systems
installation, the height of the hill or escarpment (landfill) relative to upwind
terrain is taken as 88 ft for wind load analysis.
3. Distance (upwind or downwind) from the crest to the building or structure site (x)
is assumed as 50 ft.
4. Distance upwind of crest to where the difference in ground elevation is half the
height of hill or escarpment (landfill) is measured as 120.81 feet.
5. For slope surface scenario, topographic factor (Kzt) is taken as the average of the
flat (top) surface of the landfill and ground surface.
6. Eave height and Ridge height of the solar system is taken as 2 ft and 6 ft
respectively.
119
7. Wind Pressure (qh or qz) for the structure is analyzed at z= mean height of the
structure (h) = 4 ft.
8. Effective wind area of the panels corresponding to appropriate zones for different
tilt angles and type of wind flows are analyzed. The analyses were conducted for
1 panel corresponding to Zone 3; 4 panels corresponding to Zone 3 and Zone 2;
16 panels corresponding to Zone 3, Zone 2 and zone 1.
Design Inputs and Calculations:
Wind speed (V): Range of wind speeds for the study area location lies between 140 mph
-150 mph (wind speed contours, as given in wind speed map of figure: 6-1, page 33 and
figure: 6-1B, page 35 of ASCE 7-05 or wind speed map of counties by FBC, 2008 or
Google map resources) as shown in Figure 59. The basic wind speed for Miami Dade
County, Miami is given as 146 mph as per FBC 3-second gust speed at 33ft(10m) above
ground corresponding to Exposure category “C” (FBC, 2008) and the above value is
used for the wind load analysis along with different wind speed ranging from 120 mph to
150 mph. Wind Speeds mentioned below correspond to 3-second gust wind speeds in
mph at 33 ft (10 m) above ground for Exposure Category “C.”
Importance factor (I) Importance factor =0.77 based on Wind speed velocity, for solar
systems considered as category I (from Table 6-1 of ASCE 7-05).
Directionality factor (Kd) Directionality factor = 0.85 for solar systems considered as
solid sign category (as per Table 6-4 of ASCE 7-05).
Velocity pressure exposure coefficient (Kz)
Kz = 2.01 [15/zg]2/ α
for z < 15 ft
where,
z:
Height above local ground level taken at mean height of system = 4 feet.
Nominal height of the atmospheric boundary layer = 900 ft for Exposure “C”
zg:
(Table 6-2 of ASCE 7-05)
α:
3-sec gust speed power law exponent= 9.5 for Exposure “C” (Table 6-2 of ASCE
7-05)
Hence,
Kz = 2.01 [15/900]2/ 9.5 = 0.85
Topographic factor (Kzt) for Flat (Top) surfaces of Landfill
Kzt = (1 + K1 x K2 x K3)2
K1 evaluated by interpolating H/Lh value (as per Fig. 6-4, page 45 of ASCE 7-05)
K2 evaluated by interpolating x/Lh value (as per Fig. 6-4, page 45 of ASCE 7-05)
K3 evaluated by interpolating z/Lh = h/Lh value (as per Fig. 6-4, page 45 of ASCE 7-05)
where,
120
h:
H:
Lh:
x:
Height above local ground level taken at mean height of system = 4 feet
Height of the hill or escarpment = 88 ft (assuming uniform ground level attained
on the landfill after leveling, suitable for solar systems installation).
Distance upwind of crest to where the difference in ground elevation is half of the
height of the hill or escarpment = 120.81 ft (measured from the AutoCAD
drawings of the landfill, provided by Solid Waste Department, Miami Dade
County).
Distance (upward or downwind) from the crest to the building site= 50 ft
(assumed in Auto CAD drawings of the landfill, provided by Solid Waste
Department, Miami Dade County).
H/Lh = 88 / 120.81 = 0.73
For H/Lh >0.5, Take H/Lh=0.5
Hence, K1 after interpolation= 0.43 (as per Fig. 6-4, page 45 of ASCE 7-05)
As H/Lh >0.5, Lh=2H for evaluating K2 and K3
H/Lh = x / 2H = 50/ (2x88) = 0.28
Hence, K2 after interpolation= 0.9328 (as per Fig. 6-4, page 45 of ASCE 7-05)
Z/ Lh = z / 2H = 4 / (2x88) = 0.023
Then:
K3 after interpolation= 0.956 (as per Fig. 6-4, page 45 of ASCE 7-05)
Kzt = (1 + 0.43 x 0.933 x 0.956)2 = 1.91
Topographic factor (Kzt) for Sloped surfaces of Landfill
Topographic factor (Kzt) for horizontal ground surface= 1
Topographic factor (Kzt) for flat (top) surfaces of Landfill, calculated = 1.91
Topographic factor (Kzt) for Sloped surfaces of Landfill = average Kzt of flat and
Horizontal ground surface = (1.91 + 1)/2 = 1.46
Velocity Pressure (qh) for Flat (Top) surfaces of Landfill
qh =0.00256 x Kz x Kzt x Kd x V x V x I
qh =0.00256 x 0.85 x 1.91 x 0.85 x 146 x 146 x 0.77 = 58 lbs/sq ft
Velocity Pressure (qh) for Sloped surfaces of Landfill
qh =0.00256 x Kz x Kzt x Kd x V x V x I
121
qh =0.00256 x 0.85 x 1.46 x 0.85 x 146 x 146 x 0.77 = 44.2 lbs/sq.ft.
Gust effect factor (G): Gust effect factor (G) = 0.85 for solar systems considering them
as rigid structures (as per sections 6.2, page 21 and 6.5.8, page 26 of ASCE 7-05)
Angle of Panels Placement or Tilt Angle (θ): Angle of panel’s placement or Tilt angle
corresponds to angle of plane of the panel from horizontal, measured in degrees. Tilt
angle ranges from 0° to 30º and wind load analysis for solar panels is analyzed w.r.t.
different tilt angles for each wind flow, wind direction and corresponding zones.
Wind directions: Wind forces on the solar systems acting in the directions of D=0º and
D=180° are considered.
Wind flows: Clear wind flow= Relatively unobstructed wind flow with blockage <=50%
Obstructed wind flow= Objects below roof inhibiting wind flow with blockage >50%.
Sign Convention Positive forces correspond to wind pressures acting towards the panel’s
surface. Negative forces correspond to wind pressures acting away from the panel’s
surface.
Net pressure coefficients (Cn) Cn=Net pressures (contributions from top and bottom
surfaces) at different tilt angles correspond to type of wind flows, effective wind areas
and zones (as per figure: 6-19A, page 70 of ASCE 7-05).
Net Design Wind Pressure (P): The net design wind pressure is calculated using
formula as per section 6.5.13.3, page 29 of ASCE 7-05.
P = qh x g x Cn
where,
G:
Gust effect factor.
Net pressures (contributions from top and bottom surfaces) of the panel.
Cn:
Effective Wind Area (A): The effective wind area of the panels denotes type of zones
for evaluation of wind loads. For values of A ≤ a2 , a2<A≤ 4 a2, A> 4a2 with a=
3ft(minimum), Zone 3, Zone2,Zone1 or combination of the above are chosen for wind
load analysis. The analyses were conducted for 1 panel corresponding to Zone 3; 4 panels
corresponding to Zone 3 and Zone 2; 16 panels corresponding to Zone 3, Zone 2 and
zone 1.
A:
a:
Effective wind area, in ft2 (m2).
10% of least horizontal dimension or 0.4h ,whichever is smaller but not less than
4% of least horizontal dimension or 3ft (0.9m).
122
Wind Force (F): The wind force acting on the panels with respect to different wind
speeds is calculated using the formula below.
F = Pnet × A
where,
F:
Wind force acting on the panel surfaces, in lbs.
Pnet: Net design wind pressure (sum of external and internal pressures) for calculating
wind loads on buildings or structures, in lbs/ft2 (N/m2).
A:
Effective wind area of the panel surfaces, in ft2 (m2).
Wind load analyses for both flat and sloped surfaces of NW 58th street landfill are
provided in Appendix C3 and Appendix C4, respectively.
123
APPENDIX C1. Force vs Tilt angle graphs at different wind speeds for flat surfaces on North Dade Landfill
Case-1: For Effective wind area of 1 Panel
Table C1-1. Wind force vs Tilt angle calculations at different wind speeds for single panel
For Effective wind area of 1 Panel,in sq.ft
For Effective wind area of 1 Panel,in sq.ft
Angle of
Angle
of
Wind Speed=150 mph
Wind Speed=146 mph
Panels
Panels
Clear
Obstructed
Clear
Obstructed
Placement
(or) Tilt
angle,
in degrees
Positive
forces, in
lbs
Negative
forces, in
lbs
Positive
forces, in
lbs
Negative
forces, in
lbs
Placement
(or) Tilt
angle,
in degrees
Positive
forces, in
lbs
Negative
forces, in
lbs
Positive
forces, in
lbs
Negative
forces, in
lbs
0
1269.281
-1198.77
564.1248
-1269.28
0
1202.488
-1135.68
534.4393
-1202.49
7.5
1692.374
-1480.83
846.1872
-1833.41
7.5
1603.318
-1402.9
801.6589
-1736.93
15
1903.921
-2044.95
1269.281
-2256.5
15
1803.733
-1937.34
1202.488
-2137.76
30
2750.108
-2679.59
1692.374
-2468.05
30
2605.392
-2538.59
1603.318
-2338.17
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=140 mph
Clear
Obstructed
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=130 mph
Clear
Obstructed
Angle of
Panels
Placement
(or) Tilt
angle,
in degrees
Positive
forces, in
lbs
Negative
forces, in
lbs
Positive
forces, in
lbs
Negative
forces, in
lbs
Angle of
Panels
Placement
(or) Tilt
angle,
in degrees
0
1105.685
-1044.26
491.4154
-1105.68
7.5
1474.246
-1289.97
737.1231
15
1658.527
-1781.38
30
2395.65
-2334.22
Positive
forces, in
lbs
Negative
forces, in
lbs
Positive
forces, in
lbs
0
953.3709
-900.406
423.7204 -953.371
-1597.1
7.5
1271.161
-1112.27
635.5806 -1377.09
1105.685
-1965.66
15
1430.056
-1535.99
953.3709 -1694.88
1474.246
-2149.94
30
2065.637
-2012.67
1271.161 -1853.78
124
Negative
forces, in
lbs
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=120 mph
Clear
Obstructed
Angle of Panels
Placement (or)
Tilt angle,
in degrees
Positive
forces, in
lbs
0
812.3397
-767.21 361.0399
7.5
1083.12
15
1218.51
30
1760.069
-947.73 541.5598
1308.77 812.3397
1714.94 1083.12
Negative
forces, in
lbs
Positive
forces, in
lbs
Negative
forces, in
lbs
-812.34
1173.38
1444.16
1579.55
Single Panel
Wind Force(lbs)
3000
2500
2000
Clear,positive(150 mph)
1500
Clear,positive(146 mph)
1000
Clear,positive(140 mph)
500
Clear,positive(130 mph)
0
Clear,positive(120 mph)
0
10
20
30
40
Angle of Panels Placement(degrees)
Figure C1-1. Positive wind force analysis at different wind speeds for clear wind flow
125
Single Panel
Wind Force(lbs)
2000
Obstructed,positive(150 mph)
1500
1000
Obstructed,positive(146 mph)
500
Obstructed,positive(140 mph)
0
0
10
20
30
40
Angle of Panels Placement(degrees)
Obstructed,positive(130 mph)
Figure C1-2. Positive wind force analysis at different wind speeds for obstructed wind flow
Single Panel
0
Wind Force(lbs)
‐500 0
10
20
30
Clear,negative(150 mph)
‐1000
Clear,negative(146 mph)
‐1500
Clear,negative(140 mph)
‐2000
Clear,negative(130 mph)
‐2500
‐3000
40
Clear,negative(120 mph)
Angle of Panels Placement(degrees)
Figure C1-3. Negative wind force analysis at different wind speeds for clear wind flow
126
Single Panel
0
Wind Force(lbs)
‐500
0
10
20
30
40
Obstructed,negative(150 mph)
‐1000
Obstructed,negative(146 mph)
‐1500
Obstructed,negative(140 mph)
‐2000
Obstructed,negative(130 mph)
‐2500
Obstructed,negative(120 mph)
‐3000
Angle of Panels Placement(degrees)
Figure C1-4. Negative wind force analysis at different wind speeds for obstructed wind flow
127
Case-2: For Effective wind area of 4 Panels
Table C1-2. Wind force vs Tilt angle calculations at different wind speeds for 4 panels
For Effective wind area of 4(2*2) Panels, in sq.ft
For Effective wind area of 4(2*2) Panels, in sq.ft
Angle of
Angle
of
Wind Speed=150 mph
Wind Speed=146 mph
Panels
Panels
Clear
Obstructed
Clear
Obstructed
Placement
(or) Tilt
angle,
in degrees
Positive
forces, in
lbs
Negative
forces, in
lbs
Positive
forces, in
lbs
Negative
forces, in
lbs
Placement
(or) Tilt
angle,
in degrees
Positive
forces, in
lbs
Negative
forces, in
lbs
Positive
forces, in
lbs
Negative
forces, in
lbs
0
6769.498
-6205.37
2820.624
-6769.5
0
6413.272
-5878.83
2672.196
-6413.27
7.5
9025.997
-7897.75
4512.998
-9590.12
7.5
8551.029
-7482.15
4275.514
-9085.47
15
10154.25
-10718.4
6769.498
-11846.6
15
9619.907
-10154.3
6413.272
-11223.2
30
14667.24
-14103.1
9025.997
-12974.9
30
13895.42
-13361
8551.029
-12292.1
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=140 mph
Clear
Obstructed
Angle of
Panels
Placement
(or) Tilt
angle,
in degrees
Positive
forces, in
lbs
Negative
forces, in
lbs
Positive
forces, in
lbs
0
5896.985
-5405.57
7.5
7862.646
15
30
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=130 mph
Clear
Obstructed
Negative
forces, in
lbs
Angle of
Panels
Placement
(or) Tilt
angle,
in degrees
Positive
forces, in
lbs
Negative
forces, in
lbs
Positive
forces, in
lbs
Negative
forces, in
lbs
2457.077
-5896.98
0
5084.645
-4660.92
2118.602
-5084.64
-6879.82
3931.323
-8354.06
7.5
6779.526
-5932.09
3389.763
-7203.25
8845.477
-9336.89
5896.985
-10319.7
15
7626.967
-8050.69
5084.645
-8898.13
12776.8
-12285.4
7862.646
-11302.6
30
11016.73
-10593
6779.526
-9745.57
128
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=120 mph
Clear
Obstructed
Angle of Panels
Placement (or)
Tilt angle,
in degrees
Positive
forces, in
lbs
0
4332.478
7.5
5776.638
15
6498.718
30
9387.037
Negative
forces, in
lbs
3971.44
5054.56
6859.76
-9026
Positive
forces, in
lbs
1805.199
2888.319
4332.478
5776.638
Negative
forces, in
lbs
4332.48
6137.68
7581.84
8303.92
Wind Force(lbs)
4 Panels(2*2)
16000
14000
12000
10000
8000
6000
4000
2000
0
Clear,positive(150 mph)
Clear,positive(146 mph)
Clear,positive(140 mph)
Clear,positive(130 mph)
Clear,positive(120 mph)
0
10
20
30
40
Angle of Panels Placement(degrees)
Figure C1-5. Positive wind force analysis at different wind speeds for clear wind flow
129
4 Panels(2*2)
Wind Force(lbs)
10000
8000
Obstructed,positive(150 mph)
6000
Obstructed,positive(146 mph)
4000
Obstructed,positive(140 mph)
2000
Obstructed,positive(130 mph)
0
Obstructed,positive(120 mph)
0
10
20
30
40
Angle of Panels Placement(degrees)
Figure C1-6. Positive wind force analysis at different wind speeds for obstructed wind flow
4 Panels(2*2)
0
Wind Force(lbs)
0
10
20
30
40
Clear,negative(150 mph)
‐5000
Clear,negative(146 mph)
Clear,negative(140 mph)
‐10000
Clear,negative(130 mph)
Clear,negative(120 mph)
‐15000
Angle of Panels Placement(degrees)
Figure C1-7. Negative wind force analysis at different wind speeds for clear wind flow
130
4 Panels(2*2)
0
Wind Force(lbs)
‐2000
0
10
20
30
40
‐4000
Obstructed,negative(150 mph)
‐6000
Obstructed,negative(146 mph)
‐8000
Obstructed,negative(140 mph)
Obstructed,negative(130 mph)
‐10000
Obstructed,negative(120 mph)
‐12000
‐14000
Angle of Panels Placement(degrees)
Figure C1-8.Negative wind force analysis at different wind speeds for obstructed wind flow
131
Case-3: For Effective wind area of 16 Panels
Table C1.3. Wind force vs Tilt angle calculations at different wind speeds for 16 panels
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=150 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
40616.99 -37232.2 16923.74
-40617
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=146 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
38479.63
-35273 16033.18 -38479.6
7.5
54155.98
-47386.5
27077.99
-57540.7
7.5
51306.17
-44892.9
25653.09
-54512.8
15
60925.48
-64310.2
40616.99
-71079.7
15
57719.44
-60926.1
38479.63
-67339.4
30
88003.47
-84618.7
54155.98
-77849.2
30
83372.53
-80165.9
51306.17
-73752.6
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=140 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
35381.91 -32433.4 14742.46 -35381.9
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=130 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
30507.87 -27965.5 12711.61 -30507.9
7.5
47175.88
-41278.9
23587.94
-50124.4
7.5
40677.16
-35592.5
20338.58
-43219.5
15
53072.86
-56021.4
35381.91
-61918.3
15
45761.8
-48304.1
30507.87
-53388.8
30
76660.8
-73712.3
47175.88
-67815.3
30
66100.38
-63558.1
40677.16
-58473.4
132
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=120 mph
Clear
Obstructed
Angle of Panels
Placement (or)
Positive
Negative
Positive
Negative
Tilt angle,
forces, in forces, in forces, in forces, in
in degrees
lbs
lbs
lbs
lbs
0
25994.87 -23828.6
10831.2 -25994.9
7.5
34659.83
-30327.3
17329.91
-36826.1
15
38992.31
-41158.5
25994.87
-45491
30
56322.22
-54156
34659.83
-49823.5
16 Panels(4*4)
wind Force(lbs)
100000
80000
Clear,positive(150 mph)
60000
Clear,positive(146 mph)
40000
Clear,positive(140 mph)
20000
Clear,positive(130 mph)
0
Clear,positive(120 mph)
0
10
20
30
40
Angle of Panels Placement(degrees)
Figure C1-9. Positive wind force analysis at different wind speeds for clear wind flow
133
16 Panels(4*4)
Wind Force(lbs)
60000
50000
40000
Obstructed,positive(150 mph)
30000
Obstructed,positive(146 mph)
20000
Obstructed,positive(140 mph)
10000
Obstructed,positive(130 mph)
0
0
10
20
30
40
Obstructed,positive(120 mph)
Angle of Panels Placement(degrees)
Figure C1-10. Positive wind force analysis at different wind speeds for obstructed wind flow
16 Panels(4*4)
Wind Force(lbs)
0
‐20000
0
10
20
30
40
Clear,negative(150 mph)
‐40000
Clear,negative(146 mph)
‐60000
Clear,negative(140 mph)
Clear,negative(130 mph)
‐80000
‐100000
Clear,negative(120 mph)
Angle of Panels Placement(degrees)
Figure C1-11. Negative wind force analysis at different wind speeds for clear wind flow
134
16 Panels(4*4)
0
‐10000 0
5
10
15
20
25
30
35
Wind Force(lbs)
‐20000
‐30000
Obstructed,negative(150 mph)
‐40000
Obstructed,negative(146 mph)
‐50000
Obstructed,negative(140 mph)
‐60000
Obstructed,negative(130 mph)
‐70000
Obstructed,negative(120 mph)
‐80000
‐90000
Angle of Panels Placement(degrees)
Figure C1-12. Negative wind force analysis at different wind speeds for obstructed wind flow
135
Force vs Wind speed graphs at different wind speeds
Case-1: For Effective wind area of 1 panel
Table C1.4. Wind force vs Wind speed calculations at different tilt angles for 1 panel
Total Wind Force on 1 Panel (Zone 3) at
7.5 degrees
Wind
Clear
Obstructed
Speed,in
Positive
Negative
Positive
Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
1083.12 -947.73 541.56 -1173.38
Total Wind Force on 1 Panel (Zone 3) at
0 degrees
Wind
Clear
Obstructed
Speed,in
Positive
Negative
Positive
Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
812.34
-767.21 361.04
-812.34
130
953.371 -900.406
423.72
-953.37
130
1271.16 -1112.27 635.581
-1377.09
140
1105.68 -1044.26
491.42
-1105.7
140
1474.25 -1289.97 737.123
-1597.1
146
1202.49 -1135.68
534.44
-1202.5
146
1603.32
801.659
-1736.93
150
1269.28 -1198.77
564.12
-1269.3
150
1692.37 -1480.83 846.187
-1833.41
120
Total Wind Force on 1 Panel (Zone 3) at
30 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, forces, in forces,
in lbs
in lbs
lbs
in lbs
1760.07 -1714.94 1083.12 -1579.55
-1694.88
130
2065.64
-2012.67 1271.161
-1853.78
1105.68
-1965.66
140
2395.65
-2334.22 1474.246
-2149.94
-1937.342
1202.49
-2137.76
146
2605.39
-2538.59 1603.318
-2338.17
-2044.952
1269.28
-2256.5
150
2750.11
-2679.59 1692.374
-2468.05
120
Total Wind Force on 1 Panel (Zone 3) at
15 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces,
forces,
in lbs
lbs
in lbs
in lbs
1218.51 -1308.77
812.34 -1444.16
130
1430.06
-1535.986
953.371
140
1658.53
-1781.381
146
1803.73
150
1903.92
Wind
Speed,in
mph
-1402.9
Wind
Speed,in
mph
136
Single Panel @Tilt angle = 0 degrees 1500
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
1000
500
Force vs Wind Speed,Clear,negative
0
‐500 0
50
100
150
200
‐1000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐1500
Wind Speed(mph)
Figure C1-13. Wind force analysis w.r.t different wind speeds at different tilt angle= 0 degrees for single panel
Wind Force(lbs)
Single Panel @Tilt angle = 7.5 degrees 2000
1500
1000
500
0
‐500 0
‐1000
‐1500
‐2000
‐2500
Force vs Wind Speed,Clear,positive
Force vs Wind Speed,Clear,negative
50
100
150
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C1-14. Wind force analysis w.r.t different wind speeds at different tilt angle= 7.5 degrees for single panel
137
Single Panel @ Tilt angle = 15 degrees 3000
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
2000
1000
Force vs Wind Speed,Clear,negative
0
‐1000 0
50
100
150
200
‐2000
‐3000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C1-15. Wind force analysis w.r.t different wind speeds at different tilt angle= 15 degrees for single panel
Single Panel @ Tilt angle = 30 degrees 4000
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
3000
2000
Force vs Wind Speed,Clear,negative
1000
0
‐1000 0
50
100
150
‐2000
‐3000
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C1-16. Wind force analysis w.r.t different wind speeds at different tilt angle= 30 degrees for single panel
138
Case-2: For Effective wind area of 4 panels
Table C1.5. Wind force vs Wind speed calculations at different tilt angles for 4 panels
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 0 degrees
Wind
Clear
Obstructed
Speed,in
Positive Negative Positive Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
4332.48 -3971.44 1805.2 -4332.5
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 7.5 degrees
Wind
Clear
Obstructed
Speed,in
Positive Negative Positive Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
5776.64 -5054.56 2888.32 -6137.68
130
5084.64 -4660.92
2118.6
-5084.6
130
6779.53 -5932.09 3389.76 -7203.25
140
5896.98 -5405.57
2457.1
-5897
140
7862.65 -6879.82 3931.32 -8354.06
146
6413.27 -5878.83
2672.2
-6413.3
146
8551.03 -7482.15 4275.51 -9085.47
150
6769.5
2820.6
-6769.5
150
-6205.37
120
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 15 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces,
forces,
in lbs
lbs
in lbs
in lbs
6498.72 -6859.758 4332.48 -7581.84
130
7626.97
-8050.688
140
8845.48
146
150
Wind
Speed,in
mph
9026
-7897.75
4513
-9590.12
120
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 30 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, forces, in forces,
in lbs
in lbs
lbs
in lbs
9387.04
-9026
5776.638 -8303.92
5084.64 -8898.13
130
11016.7
6779.526
-9745.57
-9336.892
5896.98 -10319.7
140
12776.8 -12285.4 7862.646
-11302.6
9619.91
-10154.35
6413.27 -11223.2
146
13895.4
8551.029
-12292.1
10154.2
-10718.37
6769.5
150
14667.2 -14103.1 9025.997
-12974.9
Wind
Speed,in
mph
-11846.6
139
-10593
-13361
4 Panels(2*2) @Tilt angle = 0 degrees Wind Force(lbs)
10000
Force vs Wind Speed,Clear,positive
5000
Force vs Wind Speed,Clear,negative
0
0
50
100
150
200
‐5000
Force vs Wind Speed,Obstructed,positive
‐10000
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C1-17. Wind force analysis w.r.t different wind speeds at different tilt angle= 0 degrees for 4 panels
4 Panels(2*2)@Tilt angle=7.5 degrees Wind Force(lbs)
10000
Force vs Wind Speed,Clear,positive
5000
0
‐5000
0
50
100
150
Force vs Wind Speed,Obstructed,positive
‐10000
‐15000
200
Force vs Wind Speed,Clear,negative
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C1-18. Wind force analysis w.r.t different wind speeds at different tilt angle= 7.5 degrees for 4 panels
140
4 Panels(2*2)@Tilt angle=15 degrees 15000
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
10000
5000
Force vs Wind Speed,Clear,negative
0
‐5000 0
50
100
150
200
‐10000
‐15000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C1-19. Wind force analysis w.r.t different wind speeds at different tilt angle= 15 degrees for 4 panels
Wind Force(lbs)
4 Panels(2*2)@Tilt angle=30 degrees 20000
15000
10000
5000
0
‐5000 0
‐10000
‐15000
‐20000
Force vs Wind Speed,Clear,positive
Force vs Wind Speed,Clear,negative
50
100
150
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C1-20. Wind force analysis w.r.t different wind speeds at different tilt angle= 30 degrees for 4 panels
141
Case-3: For Effective wind area of 16 panels
Table C1.6. Wind force vs Wind speed calculations at different tilt angles for 16 panels
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 7.5 degrees
Wind
Clear
Obstructed
Speed,in
Positive
Negative
Positive
Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
34659.8 -30327.3 17329.9 -36826.1
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 0 degrees
Wind
Clear
Obstructed
Speed,in
Positive
Negative
Positive
Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
25994.9 -23828.6 10831
-25995
130
30507.9 -27965.5
12712
-30508
130
40677.2 -35592.5 20338.6 -43219.5
140
35381.9 -32433.4
14742
-35382
140
47175.9 -41278.9 23587.9 -50124.4
146
38479.6
-35273
16033
-38480
146
51306.2 -44892.9 25653.1 -54512.8
150
40617
-37232.2
16924
-40617
150
-47386.5
27078
-57540.7
120
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 30 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, forces, in forces,
in lbs
in lbs
lbs
in lbs
56322.2 -54156 34659.83 -49823.5
30507.9 -53388.8
130
66100.4 -63558.1 40677.16
-58473.4
-56021.35
35381.9 -61918.3
140
76660.8 -73712.3 47175.88
-67815.3
57719.4
-60926.08
38479.6 -67339.4
146
83372.5 -80165.9 51306.17
-73752.6
60925.5
-64310.23
150
88003.5 -84618.7 54155.98
-77849.2
120
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 15 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces,
forces,
in lbs
lbs
in lbs
in lbs
38992.3 -41158.55 25994.9 -45491
130
45761.8
-48304.13
140
53072.9
146
150
Wind
Speed,in
mph
54156
40617
Wind
Speed,in
mph
-71079.7
142
16 Panels(4*4)@Tilt angle = 0 degrees 60000
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
40000
20000
Force vs Wind Speed,Clear,negative
0
‐20000
0
50
100
150
200
‐40000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐60000
Wind Speed(mph)
Figure C1-21. Wind force analysis w.r.t different wind speeds at different tilt angle= 0 degrees for 16 panels
16 Panels(4*4)@Tilt angle=7.5 degrees 60000
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
40000
20000
0
‐20000 0
50
100
150
‐40000
‐60000
‐80000
200
Force vs Wind Speed,Clear,negative
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C1-22. Wind force analysis w.r.t different wind speeds at different tilt angle= 7.5 degrees for 16 panels
143
16 Panels(4*4)@Tilt angle=15 degrees Wind Force(lbs)
100000
Force vs Wind Speed,Clear,positive
50000
Force vs Wind Speed,Clear,negative
0
0
50
100
150
200
‐50000
Force vs Wind Speed,Obstructed,positive
‐100000
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C1-23. Wind force analysis w.r.t different wind speeds at different tilt angle= 15 degrees for 16 panels
16 Panels(4*4)@Tilt angle=30 degrees Wind Force(lbs)
100000
Force vs Wind Speed,Clear,positive
50000
Force vs Wind Speed,Clear,negative
0
0
50
100
150
200
‐50000
Force vs Wind Speed,Obstructed,positive
‐100000
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C1-24. Wind force analysis w.r.t different wind speeds at different tilt angle= 0 degrees for 16 panel
144
APPENDIX C2 Wind Load Analysis for Sloped Surfaces of North Dade Landfill
Force vs Tilt angle graphs at different wind speeds:
Case-1: For Effective wind area of 1 Panel
Table C2.1. Wind force vs Tilt angle calculations at different wind speeds for single panel
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=150 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in forces, in
angle,
lbs
in lbs
lbs
lbs
in degrees
0
1049.3 -991.005 466.3554
-1049.3
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=146 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in forces, in
angle,
lbs
in lbs
lbs
lbs
in degrees
0
994.0831 -938.856 441.8147 -994.083
7.5
1399.066
-1224.18
699.5331
-1515.65
7.5
1325.444
-1159.76
662.7221
-1435.9
15
1573.949
-1690.54
1049.3
-1865.42
15
1491.125
-1601.58
994.0831
-1767.26
30
2273.482
-2215.19
1399.066
-2040.3
30
2153.847
-2098.62
1325.444
-1932.94
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=140 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
914.0565 -863.276 406.2474 -914.057
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=130 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
788.1406 -744.355 350.2847 -788.141
7.5
1218.742
-1066.4
609.371
-1320.3
7.5
1050.854
-919.497
525.4271
-1138.43
15
1371.085
-1472.65
914.0565
-1624.99
15
1182.211
-1269.78
788.1406
-1401.14
30
1980.456
-1929.67
1218.742
-1777.33
30
1707.638
-1663.85
1050.854
-1532.5
145
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=120 mph
Clear
Obstructed
Angle of Panels
Placement (or)
Positive
Negative
Positive
Negative
Tilt angle,
forces, in forces, in forces, in forces, in
in degrees
lbs
lbs
lbs
lbs
0
671.5517 -634.243 298.4674 -671.552
7.5
895.4023
-783.477
447.7012
-970.019
15
1007.328
-1081.94
671.5517
-1193.87
30
1455.029
-1417.72
895.4023
-1305.8
Single Panel
Wind Force(lbs)
2500
2000
Clear,positive(150 mph)
1500
Clear,positive(146 mph)
1000
Clear,positive(140 mph)
500
Clear,positive(130 mph)
0
Clear,positive(120 mph)
0
10
20
30
40
Angle of Panels Placement(degrees)
Figure C2-1. Positive wind force analysis at different wind speeds for clear wind flow
146
Single Panel
Wind Force(lbs)
1500
1000
Obstructed,positive(150 mph)
Obstructed,positive(146 mph)
500
Obstructed,positive(140 mph)
Obstructed,positive(130 mph)
0
0
10
20
30
40
Obstructed,positive(120 mph)
Angle of Panels Placement(degrees)
Figure C2-2. Positive wind force analysis at different wind speeds for obstructed wind flow
Single Panel
Wind Force(lbs)
0
‐500
0
10
20
30
40
Clear,negative(150 mph)
‐1000
Clear,negative(146 mph)
‐1500
Clear,negative(140 mph)
Clear,negative(130 mph)
‐2000
‐2500
Clear,negative(120 mph)
Angle of Panels Placement(degrees)
Figure C2-3. Negative wind force analysis at different wind speeds for clear wind flow
147
Single Panel
Wind Force(lbs)
0
‐500
0
10
20
30
40
Obstructed,negative(150 mph)
‐1000
Obstructed,negative(146 mph)
‐1500
Obstructed,negative(140 mph)
‐2000
Obstructed,negative(130 mph)
‐2500
Obstructed,negative(120 mph)
Angle of Panels Placement(degrees)
Figure C2-4. Negative wind force analysis at different wind speeds for obstructed wind flow
148
Case-2: For Effective wind area of 4 Panels
Table C2.2. Wind force vs Tilt angle calculations at different wind speeds for 4 panels
For Effective wind area of 4(2*2) Panels, in sq.ft
Angle of
Wind Speed=150 mph
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
5596.265 -5129.91 2331.777 -5596.26
For Effective wind area of 4(2*2) Panels, in sq.ft
Angle of
Wind Speed=146 mph
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
5301.777 -4859.96 2209.074 -5301.78
7.5
7461.686
-6528.98
3730.843
-7928.04
7.5
7069.036
-6185.41
3534.518
-7510.85
15
8394.397
-8860.75
5596.265
-9793.46
15
7952.665
-8394.48
5301.777
-9278.11
30
12125.24
-11658.9
7461.686
-10726.2
30
11487.18
-11045.4
7069.036
-10161.7
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=140 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in forces, forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
4874.968 -4468.72 2031.237 -4874.97
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=130 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces, forces, in forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
4203.416 -3853.13 1751.424 -4203.42
7.5
6499.958
-5687.46
3249.979
-6906.2
7.5
5604.555
-4903.99
2802.278
-5954.84
15
7312.452
-7718.7
4874.968
-8531.19
15
6305.125
-6655.41
4203.416
-7355.98
30
10562.43
-10156.2
6499.958
-9343.69
30
9107.402
-8757.12
5604.555
-8056.55
149
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=120 mph
Clear
Obstructed
Angle of Panels
Placement (or)
Positive
Negative
Positive
Negative
Tilt angle,
forces, in forces, in forces, in forces, in
in degrees
lbs
lbs
lbs
lbs
0
3581.609 -3283.14 1492.337 -3581.61
7.5
4775.479
-4178.54
2387.74
-5073.95
15
5372.414
-5670.88
3581.609
-6267.82
30
7760.153
-7461.69
4775.479
-6864.75
4 Panels(2*2)
14000
Wind Force(lbs)
12000
Clear,positive(150 mph)
10000
Clear,positive(146 mph)
8000
6000
Clear,positive(140 mph)
4000
Clear,positive(130 mph)
2000
Clear,positive(120 mph)
0
0
10
20
30
40
Angle of Panels Placement(degrees)
Figure C2-5. Positive wind force analysis at different wind speeds for clear wind flow
150
Wind Force(lbs)
4 Panels(2*2)
8000
7000
6000
5000
4000
3000
2000
1000
0
Obstructed,positive(150 mph)
Obstructed,positive(146 mph)
Obstructed,positive(140 mph)
Obstructed,positive(130 mph)
0
10
20
30
40
Obstructed,positive(120 mph)
Angle of Panels Placement(degrees)
Figure C2-6. Positive wind force analysis at different wind speeds for obstructed wind flow
4 Panels(2*2)
0
‐2000 0
10
20
30
40
Wind Force(lbs)
‐4000
Clear,negative(150 mph)
Clear,negative(146 mph)
‐6000
Clear,negative(140 mph)
‐8000
Clear,negative(130 mph)
‐10000
Clear,negative(120 mph)
‐12000
‐14000
Angle of Panels Placement(degrees)
Figure C2-7. Negative wind force analysis at different wind speeds for clear wind flow
151
4 Panels(2*2)
0
Wind Force(lbs)
‐2000
0
10
20
30
40
Obstructed,negative(150 mph)
‐4000
Obstructed,negative(146 mph)
‐6000
Obstructed,negative(140 mph)
‐8000
Obstructed,negative(130 mph)
‐10000
Obstructed,negative(120 mph)
‐12000
Angle of Panels Placement(degrees)
Figure C2-8. Negative wind force analysis at different wind speeds for obstructed wind flow
152
Case-3: For Effective wind area of 16 panels
Table C2.3. Wind force vs Tilt angle calculations at different wind speeds for 16 panels
For Effective wind area of 16(4*4) Panels, in sq.ft
Angle of
Wind Speed=150 mph
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
33577.59 -30779.5 13990.66 -33577.6
For Effective wind area of 16(4*4) Panels, in sq.ft
Angle of
Wind Speed=146 mph
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
31810.66 -29159.8 13254.44 -31810.7
7.5
44770.12
-39173.9
22385.06
-47568.2
7.5
42414.21
-37112.4
21207.11
-45065.1
15
50366.38
-53164.5
33577.59
-58760.8
15
47715.99
-50366.9
31810.66
-55668.7
30
72751.44
-69953.3
44770.12
-64357
30
68923.1
-66272.2
42414.21
-60970.4
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=140 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
29249.81 -26812.3 12187.42 -29249.8
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=130 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
25220.5 -23118.8 10508.54 -25220.5
7.5
38999.75
-34124.8
19499.87
-41437.2
7.5
33627.33
-29423.9
16813.67
-35729
15
43874.71
-46312.2
29249.81
-51187.2
15
37830.75
-39932.5
25220.5
-44135.9
30
63374.59
-60937.1
38999.75
-56062.1
30
54644.41
-52542.7
33627.33
-48339.3
153
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=120 mph
Clear
Obstructed
Angle of Panels
Placement (or)
Positive
Negative
Positive
Negative
Tilt angle,
forces, in forces, in forces, in forces, in
in degrees
lbs
lbs
lbs
lbs
0
21489.66 -19698.9 8954.023 -21489.7
7.5
28652.87
-25071.3
14326.44
-30443.7
15
32234.48
-34025.3
21489.66
-37606.9
30
46560.92
-44770.1
28652.87
-41188.5
16 Panels(4*4)
80000
wind Force(lbs)
70000
60000
Clear,positive(150 mph)
50000
Clear,positive(146 mph)
40000
Clear,positive(140 mph)
30000
Clear,positive(130 mph)
20000
Clear,positive(120 mph)
10000
0
0
10
20
30
40
Angle of Panels Placement(degrees)
Figure C2-9. Positive wind force analysis at different wind speeds for clear wind flow
154
16 Panels(4*4)
Wind Force(lbs)
50000
40000
Obstructed,positive(150 mph)
30000
Obstructed,positive(146 mph)
20000
Obstructed,positive(140 mph)
10000
Obstructed,positive(130 mph)
Obstructed,positive(120 mph)
0
0
10
20
30
40
Angle of Panels Placement(degrees)
Figure C2-10. Positive wind force analysis at different wind speeds for obstructed wind flow
16 Panels(4*4)
0
Wind Force(lbs)
0
10
20
30
‐20000
40
Clear,negative(150 mph)
Clear,negative(146 mph)
Clear,negative(140 mph)
‐40000
Clear,negative(130 mph)
‐60000
‐80000
Clear,negative(120 mph)
Angle of Panels Placement(degrees)
Figure C2-11. Negative wind force analysis at different wind speeds for clear wind flow
155
16 Panels(4*4)
0
Wind Force(lbs)
‐10000
0
10
20
30
40
‐20000
Obstructed,negative(150 mph)
‐30000
Obstructed,negative(146 mph)
‐40000
Obstructed,negative(140 mph)
‐50000
Obstructed,negative(130 mph)
‐60000
Obstructed,negative(120 mph)
‐70000
Angle of Panels Placement(degrees)
Figure C2-12. Negative wind force analysis at different wind speeds for obstructed wind flow
156
Force vs Wind speed graphs at different wind speeds:
Case-1: For Effective wind area of 1panel
Table C2.4. Wind force vs Wind speed calculations at different tilt angles for 1 panel
Total Wind Force on 1 Panel (Zone 3) at
7.5 degrees
Wind
Clear
Obstructed
Speed,in
Positive
Negative
Positive
Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
895.402 -783.477 447.701 -970.019
Total Wind Force on 1 Panel (Zone 3) at
0 degrees
Wind
Clear
Obstructed
Speed,in
Positive
Negative
Positive
Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
671.552 -634.243 298.47
-671.55
130
788.141 -744.355
350.28
-788.14
130
1050.85 -919.497 525.427
140
914.057 -863.276
406.25
-914.06
140
1218.74
609.371
-1320.3
146
994.083 -938.856
441.81
-994.08
146
1325.44 -1159.76 662.722
-1435.9
150
1049.3
466.36
-1049.3
150
1399.07 -1224.18 699.533
-1515.65
-991.005
120
Total Wind Force on 1 Panel (Zone 3) at 30
degrees
Clear
Obstructed
Positive Negative
Positive
Negative
forces,
forces, in forces, in forces, in
in lbs
lbs
lbs
lbs
1455.03 -1417.72 895.4023
-1305.8
-1401.14
130
1707.64
-1663.85
1050.854
-1532.5
914.057
-1624.99
140
1980.46
-1929.67
1218.742
-1777.33
-1601.578
994.083
-1767.26
146
2153.85
-2098.62
1325.444
-1932.94
-1690.538
1049.3
-1865.42
150
2273.48
-2215.19
1399.066
-2040.3
120
Total Wind Force on 1 Panel (Zone 3) at 15
degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces,
forces, in
in lbs
lbs
in lbs
lbs
1007.33 -1081.944 671.552
-1193.87
130
1182.21
-1269.782
788.141
140
1371.08
-1472.647
146
1491.12
150
1573.95
Wind
Speed,in
mph
-1066.4
-1138.43
Wind
Speed,in
mph
157
Single Panel @Tilt angle = 0 degrees 1500
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
1000
500
Force vs Wind Speed,Clear,negative
0
‐500 0
50
100
150
200
‐1000
‐1500
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C2-13. Wind force analysis w.r.t different wind speeds at different tilt angle= 0 degrees for 1 panel
Single Panel @Tilt angle = 7.5 degrees 2000
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
1500
1000
Force vs Wind Speed,Clear,negative
500
0
‐500 0
50
100
150
‐1000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐1500
‐2000
200
Wind Speed(mph)
Figure C2-14. Wind force analysis w.r.t different wind speeds at different tilt angle= 7.5 degrees for 1 panel
158
Single Panel @ Tilt angle = 15 degrees Wind Force(lbs)
2000
1000
0
‐1000
0
50
100
150
200
‐2000
‐3000
Force vs Wind Speed,Clear,positive
Force vs Wind Speed,Clear,negative
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C2-15. Wind force analysis w.r.t different wind speeds at different tilt angle= 15 degrees for 1 panel
Single Panel @ Tilt angle = 30 degrees 3000
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
2000
1000
Force vs Wind Speed,Clear,negative
0
‐1000 0
50
100
150
‐2000
‐3000
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C2-16. Wind force analysis w.r.t different wind speeds at different tilt angle= 30 degrees for 1 panel
159
Case-1: For Effective wind area of 4 panels
Table C2.5. Wind force vs Wind speed calculations at different tilt angles for 4 panels
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 0 degrees
Wind
Clear
Obstructed
Speed,in
Positive Negative Positive Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
3581.61 -3283.14 1492.3 -3581.6
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 7.5 degrees
Wind
Clear
Obstructed
Speed,in
Positive Negative Positive Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
4775.48 -4178.54 2387.74 -5073.95
130
4203.42 -3853.13
1751.4
-4203.4
130
5604.56 -4903.99 2802.28 -5954.84
140
4874.97 -4468.72
2031.2
-4875
140
6499.96 -5687.46 3249.98
146
5301.78 -4859.96
2209.1
-5301.8
146
7069.04 -6185.41 3534.52 -7510.85
150
5596.26 -5129.91
2331.8
-5596.3
150
7461.69 -6528.98 3730.84 -7928.04
120
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 15 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces,
forces,
in lbs
lbs
in lbs
in lbs
5372.41 -5670.881 3581.61 -6267.82
130
6305.12
-6655.409
140
7312.45
146
150
Wind
Speed,in
mph
-6906.2
120
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 30 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, forces, in forces,
in lbs
in lbs
lbs
in lbs
7760.15 -7461.69 4775.479 -6864.75
4203.42 -7355.98
130
9107.4
-8757.12
5604.555
-8056.55
-7718.7
4874.97 -8531.19
140
10562.4
-10156.2
6499.958
-9343.69
7952.66
-8394.48
5301.78 -9278.11
146
11487.2
-11045.4
7069.036
-10161.7
8394.4
-8860.752
5596.26 -9793.46
150
12125.2
-11658.9
7461.686
-10726.2
Wind
Speed,in
mph
160
4 Panels(2*2) @Tilt angle = 0 degrees Wind Force(lbs)
10000
Force vs Wind Speed,Clear,positive
5000
Force vs Wind Speed,Clear,negative
0
0
50
100
150
200
‐5000
Force vs Wind Speed,Obstructed,positive
‐10000
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C2-17. Wind force analysis w.r.t different wind speeds at different tilt angle= 0 degrees for 4 panels
4 Panels(2*2)@Tilt angle=7.5 degrees Wind Force(lbs)
10000
Force vs Wind Speed,Clear,positive
5000
Force vs Wind Speed,Clear,negative
0
0
50
100
150
‐5000
‐10000
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C2-18. Wind force analysis w.r.t different wind speeds at different tilt angle= 7.5 degrees for 4 panels
161
4 Panels(2*2)@Tilt angle=15 degrees Wind Force(lbs)
10000
Force vs Wind Speed,Clear,positive
5000
0
‐5000
0
50
100
150
200
Force vs Wind Speed,Clear,negative
Force vs Wind Speed,Obstructed,positive
‐10000
Force vs Wind Speed,Obstructed,negative
‐15000
Wind Speed(mph)
Figure C2-19. Wind force analysis w.r.t different wind speeds at different tilt angle= 15 degrees for 4 panels
4 Panels(2*2)@Tilt angle=30 degrees 15000
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
10000
5000
Force vs Wind Speed,Clear,negative
0
‐5000 0
50
100
150
‐10000
‐15000
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C2-20. Wind force analysis w.r.t different wind speeds at different tilt angle= 30 degrees for 4 panels
162
Case-1: For Effective wind area of 16 panels
Table C2.6. Wind force vs Wind speed calculations at different tilt angles for 16 panels
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 7.5 degrees
Wind
Clear
Obstructed
Speed,in
Positive Negative Positive Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
28652.9 -25071.3 14326.4 -30443.7
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 0 degrees
Wind
Clear
Obstructed
Speed,in
Positive Negative Positive Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
21489.7 -19698.9
8954
-21490
130
25220.5 -23118.8
10509
-25220
130
33627.3 -29423.9 16813.7
140
29249.8 -26812.3
12187
-29250
140
38999.7 -34124.8 19499.9 -41437.2
146
31810.7 -29159.8
13254
-31811
146
42414.2 -37112.4 21207.1 -45065.1
150
33577.6 -30779.5
13991
-33578
150
44770.1 -39173.9 22385.1 -47568.2
120
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 30 degrees
Clear
Obstructed
Positive Negative
Positive
Negative
forces,
forces, in forces, in forces, in
in lbs
lbs
lbs
lbs
46560.9 -44770.1 28652.87 -41188.5
-44135.9
130
54644.4
-52542.7
33627.33
-48339.3
29249.8
-51187.2
140
63374.6
-60937.1
38999.75
-56062.1
-50366.88
31810.7
-55668.7
146
68923.1
-66272.2
42414.21
-60970.4
-53164.51
33577.6
-58760.8
150
72751.4
-69953.3
44770.12
-64357
120
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 15 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces,
forces, in
in lbs
lbs
in lbs
lbs
32234.5 -34025.29 21489.7 -37606.9
130
37830.7
-39932.46
25220.5
140
43874.7
-46312.2
146
47716
150
50366.4
Wind
Speed,in
mph
-35729
Wind
Speed,in
mph
163
16 Panels(4*4)@Tilt angle = 0 degrees 40000
Wind Force(lbs)
30000
Force vs Wind Speed,Clear,positive
20000
10000
Force vs Wind Speed,Clear,negative
0
‐10000 0
50
100
150
200
‐20000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐30000
‐40000
Wind Speed(mph)
Figure C2-21. Wind force analysis w.r.t different wind speeds at different tilt angle= 0 degrees for 16 panels
16 Panels(4*4)@Tilt angle=7.5 degrees 60000
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
40000
20000
Force vs Wind Speed,Clear,negative
0
‐20000 0
50
100
150
‐40000
‐60000
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C2-22. Wind force analysis w.r.t different wind speeds at different tilt angle= 7.5 degrees for 16 panels
164
16 Panels(4*4)@Tilt angle=15 degrees Wind Force(lbs)
100000
Force vs Wind Speed,Clear,positive
50000
Force vs Wind Speed,Clear,negative
0
0
50
100
150
200
‐50000
Force vs Wind Speed,Obstructed,positive
‐100000
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C2-23. Wind force analysis w.r.t different wind speeds at different tilt angle= 15 degrees for 16 panels
16 Panels(4*4)@Tilt angle=30 degrees Wind Force(lbs)
100000
Force vs Wind Speed,Clear,positive
50000
Force vs Wind Speed,Clear,negative
0
0
50
100
150
200
‐50000
Force vs Wind Speed,Obstructed,positive
‐100000
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C2-24. Wind force analysis w.r.t different wind speeds at different tilt angle= 30 degrees for 16 panel
165
APPENDIX C3 Wind Load Analysis For Sloped Surfaces of North West 58th Street Landfill
Wind Load Analysis For Flat (Top) Surfaces of Landfill:
Force vs Tilt angle graphs at different wind speeds:
Case-1: For Effective wind area of 1 Panel
Table C3-1. Wind force vs Tilt angle calculations at different wind speeds for single panel
For Effective wind area of 1 Panel,in sq.ft
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=146 mph
Wind Speed=150 mph
Angle of
Angle of
Panels
Panels
Clear
Obstructed
Clear
Obstructed
Placement
Placement
Positive Negative Positive Negative
Positive Negative Positive Negative
(or) Tilt
(or) Tilt
forces, in forces, in forces, in forces, in
forces, in forces, in forces, in forces, in
angle,
angle,
lbs
lbs
lbs
lbs
lbs
lbs
lbs
lbs
in degrees
in degrees
0
1587.273 -1499.09 705.4547 -1587.27
0
1503.747 -1420.21 668.3321 -1503.75
7.5
2116.364 -1851.82 1058.182 -2292.73
7.5
2004.996 -1754.37 1002.498 -2172.08
15
2380.91 -2557.27 1587.273 -2821.82
15
2255.621
-2422.7 1503.747 -2673.33
30
3439.092 -3350.91 2116.364 -3086.36
30
3258.119 -3174.58 2004.996 -2923.95
For Effective wind area of 1 Panel, in sq.ft
Wind Speed=140 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
1382.691 -1305.88 614.5294 -1382.69
7.5
1843.588 -1613.14 921.7941 -1997.22
15
2074.037 -2227.67 1382.691 -2458.12
30
2995.831 -2919.01 1843.588 -2688.57
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=130 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
1192.218 -1125.98 529.8749 -1192.22
7.5
1589.625 -1390.92 794.8123 -1722.09
15
1788.328
-1920.8 1192.218
-2119.5
30
2583.14 -2516.91 1589.625
-2318.2
166
Angle of Panels
Placement (or) Tilt
angle,
in degrees
0
7.5
15
30
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=120 mph
Clear
Obstructed
Positive
forces, in lbs
Negative
forces, in lbs
1015.855
1354.473
1523.782
2201.019
-959.418
-1185.16
-1636.65
-2144.58
Positive
forces, in lbs
451.491
677.2365
1015.855
1354.473
Negative
forces, in lbs
-1015.85
-1467.35
-1805.96
-1975.27
Wind Force(lbs)
Single Panel
4000
3500
3000
2500
2000
1500
1000
500
0
Clear,positive(150 mph)
Clear,positive(146 mph)
Clear,positive(140 mph)
Clear,positive(130 mph)
0
10
20
30
40
Clear,positive(120 mph)
Angle of Panels Placement(degrees)
Figure C3-1. Positive wind force analysis at different wind speeds for clear wind flow
167
Single Panel
Wind Force(lbs)
2500
2000
Obstructed,positive(150 mph)
1500
Obstructed,positive(146 mph)
1000
500
Obstructed,positive(140 mph)
0
Obstructed,positive(130 mph)
0
10
20
30
40
Obstructed,positive(120 mph)
Angle of Panels Placement(degrees)
Figure C3-2. Positive wind force analysis at different wind speeds for obstructed wind flow
Single Panel
0
Wind Force(lbs)
‐500 0
10
20
30
‐1000
Clear,negative(150 mph)
‐1500
Clear,negative(146 mph)
‐2000
Clear,negative(140 mph)
‐2500
Clear,negative(130 mph)
‐3000
Clear,negative(120 mph)
‐3500
‐4000
40
Angle of Panels Placement(degrees)
Figure C3-3. Negative wind force analysis at different wind speeds for clear wind flow
168
Single Panel
0
Wind Force(lbs)
‐500 0
10
20
30
40
Obstructed,negative(150 mph)
‐1000
Obstructed,negative(146 mph)
‐1500
Obstructed,negative(140 mph)
‐2000
Obstructed,negative(130 mph)
‐2500
Obstructed,negative(120 mph)
‐3000
‐3500
Angle of Panels Placement(degrees)
Figure C3-4. Negative wind force analysis at different wind speeds for obstructed wind flow
169
Case-2: For Effective wind area of 4 Panels
Table C3-2. Wind force vs Tilt angle calculations at different wind speeds for 4 panels
For Effective wind area of 4(2*2) Panels, in sq.ft
Angle of
Wind Speed=150 mph
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in forces, in forces, in forces, in
angle,
lbs
lbs
lbs
lbs
in degrees
0
8465.456
-7760
3527.273 -8465.46
7.5
11287.27 -9876.37 5643.637 -11992.7
15
12698.18 -13403.6 8465.456 -14814.5
30
18341.82 -17636.4 11287.27 -16225.5
For Effective wind area of 4(2*2) Panels, in sq.ft
Angle of
Wind Speed=146 mph
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in forces, in forces, in forces, in
angle,
lbs
lbs
lbs
lbs
in degrees
0
8019.985 -7351.65 3341.66 -8019.99
7.5
10693.31 -9356.65 5346.657 -11361.6
15
12029.98 -12698.3 8019.985
-14035
30
17376.63 -16708.3 10693.31 -15371.6
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=140 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
7374.353 -6759.82 3072.647 -7374.35
7.5
9832.471 -8603.41 4916.235
-10447
15
11061.53 -11676.1 7374.353 -12905.1
30
15977.76 -15363.2 9832.471 -14134.2
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=130 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
6358.498 -5828.62 2649.374 -6358.5
7.5
8477.998 -7418.25 4238.999 -9007.87
15
9537.747 -10067.6 6358.498 -11127.4
30
13776.75 -13246.9 8477.998 -12187.1
170
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=120 mph
Angle of Panels
Clear
Obstructed
Placement (or) Tilt
Positive
Negative
Positive
Negative
angle,
in
forces, in lbs forces, in lbs forces, in lbs forces, in lbs
degrees
0
5417.892
-4966.4
2257.455
-5417.89
7.5
7223.856
-6320.87
3611.928
-7675.35
15
8126.838
-8578.33
5417.892
-9481.31
30
11738.77
-11287.3
7223.856
-10384.3
4 Panels(2*2)
Wind Force(lbs)
20000
15000
Clear,positive(150 mph)
10000
Clear,positive(146 mph)
5000
Clear,positive(140 mph)
Clear,positive(130 mph)
0
0
10
20
30
40
Clear,positive(120 mph)
Angle of Panels Placement(degrees)
Figure C3-5. Positive wind force analysis at different wind speeds for clear wind flow
171
4 Panels(2*2)
Wind Force(lbs)
12000
10000
8000
Obstructed,positive(150 mph)
6000
Obstructed,positive(146 mph)
4000
Obstructed,positive(140 mph)
2000
Obstructed,positive(130 mph)
0
0
5
10
15
20
25
30
35
Obstructed,positive(120 mph)
Angle of Panels Placement(degrees)
Figure C3-6. Positive wind force analysis at different wind speeds for obstructed wind flow
4 Panels(2*2)
0
0
10
20
30
Wind Force(lbs)
‐5000
40
Clear,negative(150 mph)
Clear,negative(146 mph)
‐10000
Clear,negative(140 mph)
Clear,negative(130 mph)
‐15000
Clear,negative(120 mph)
‐20000
Angle of Panels Placement(degrees)
Figure C3-7. Negative wind force analysis at different wind speeds for clear wind flow
172
4 Panels(2*2)
0
Wind Force(lbs)
0
5
10
15
20
25
‐5000
30
35
Obstructed,negative(150 mph)
Obstructed,negative(146 mph)
‐10000
Obstructed,negative(140 mph)
Obstructed,negative(130 mph)
‐15000
Obstructed,negative(120 mph)
‐20000
Angle of Panels Placement(degrees)
Figure C3-8. Negative wind force analysis at different wind speeds for obstructed wind flow
173
Case-3: For Effective wind area of 16 Panels
Table C3-3. Wind force vs Tilt angle calculations at different wind speeds for 16 panels
For Effective wind area of 16(4*4) Panels, in sq.ft
Angle of
Wind Speed=150 mph
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in forces, in forces, in forces, in
angle,
lbs
lbs
lbs
lbs
in degrees
0
50792.74
-46560 21163.64 -50792.7
7.5
67723.65 -59258.2 33861.82 -71956.4
15
76189.11 -80421.8 50792.74 -88887.3
30
110050.9 -105818 67723.65 -97352.7
For Effective wind area of 16(4*4) Panels, in sq.ft
Angle of
Wind Speed=146 mph
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in forces, in forces, in forces, in
angle,
lbs
lbs
lbs
lbs
in degrees
0
48119.91 -44109.9 20049.96 -48119.9
7.5
64159.88 -56139.9 32079.94 -68169.9
15
72179.87 -76189.9 48119.91 -84209.8
30
104259.8 -100250 64159.88 -92229.8
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=140 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
44246.12 -40558.9 18435.88 -44246.1
7.5
58994.82 -51620.5 29497.41
-62682
15
66369.18 -70056.4 44246.12 -77430.7
30
95866.59 -92179.4 58994.82 -84805.1
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=130 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
38150.99 -34971.7 15896.25
-38151
7.5
50867.99 -44509.5 25433.99 -54047.2
15
57226.48 -60405.7 38150.99 -66764.2
30
82660.48 -79481.2 50867.99 -73122.7
174
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=120 mph
Clear
Obstructed
Angle of Panels
Placement (or) Tilt
Positive
Negative
Positive
Negative
angle, in degrees
forces, in lbs forces, in lbs forces, in lbs forces, in lbs
0
32507.35
-29798.4
13544.73
-32507.4
7.5
43343.14
-37925.2
21671.57
-46052.1
15
48761.03
-51470
32507.35
-56887.9
30
70432.6
-67723.6
43343.14
-62305.8
16 Panels(4*4)
120000
wind Force(lbs)
100000
80000
Clear,positive(150 mph)
60000
Clear,positive(146 mph)
40000
Clear,positive(140 mph)
20000
Clear,positive(130 mph)
0
Clear,positive(120 mph)
0
5
10
15
20
25
30
35
Angle of Panels Placement(degrees)
Figure C3-9. Positive wind force analysis at different wind speeds for clear wind flow
175
80000
70000
60000
50000
40000
30000
20000
10000
0
Obstructed,positive(150 mph)
Obstructed,positive(146 mph)
Obstructed,positive(140 mph)
Obstructed,positive(130 mph)
0
5
10
15
20
25
30
35
Obstructed,positive(120 mph)
Angle of Panels Placement(degrees)
Figure C3-10. Positive wind force analysis at different wind speeds for obstructed wind flow
16 Panels(4*4)
0
‐20000 0
Wind Force(lbs)
Wind Force(lbs)
16 Panels(4*4)
10
20
30
Clear,negative(150 mph)
‐40000
Clear,negative(146 mph)
‐60000
Clear,negative(140 mph)
‐80000
Clear,negative(130 mph)
‐100000
‐120000
40
Clear,negative(120 mph)
Angle of Panels Placement(degrees)
Figure C3-11. Negative wind force analysis at different wind speeds for clear wind flow
176
16 Panels(4*4)
0
Wind Force(lbs)
‐20000
0
5
10
15
20
25
30
35
Obstructed,negative(150 mph)
‐40000
Obstructed,negative(146 mph)
‐60000
Obstructed,negative(140 mph)
‐80000
Obstructed,negative(130 mph)
Obstructed,negative(120 mph)
‐100000
‐120000
Angle of Panels Placement(degrees)
Figure C3-12. Negative wind force analysis at different wind speeds for obstructed wind flow
177
Force vs Wind speed graphs at different wind speeds:
Case-1: For Effective wind area of 1 panel
Table C3-4. Wind force vs Wind speed calculations at different tilt angles for 1 panel
Wind
Speed,in
mph
120
130
140
146
150
Wind
Speed,in
mph
120
130
140
146
150
Total Wind Force on 1 Panel (Zone 3) at
0 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
1015.85 -959.418 451.49
-1015.9
1192.22 -1125.98 529.87
-1192.2
1382.69 -1305.88 614.53
-1382.7
1503.75 -1420.21 668.33
-1503.7
1587.27 -1499.09 705.45
-1587.3
Wind
Speed,in
mph
120
130
140
146
150
Total Wind Force on 1 Panel (Zone 3) at 15
degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces,
forces, in
in lbs
lbs
in lbs
lbs
1523.78 -1636.655 1015.85 -1805.96
1788.33 -1920.796 1192.22
-2119.5
2074.04 -2227.669 1382.69 -2458.12
2255.62 -2422.704 1503.75 -2673.33
2380.91 -2557.273 1587.27 -2821.82
Wind
Speed,in
mph
120
130
140
146
150
178
Total Wind Force on 1 Panel (Zone 3) at
7.5 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
1354.47 -1185.16 677.236 -1467.35
1589.62 -1390.92 794.812 -1722.09
1843.59 -1613.14 921.794 -1997.22
2005
-1754.37 1002.5 -2172.08
2116.36 -1851.82 1058.18 -2292.73
Total Wind Force on 1 Panel (Zone 3) at 30
degrees
Clear
Obstructed
Positive Negative
Positive
Negative
forces,
forces, in forces, in forces, in
in lbs
lbs
lbs
lbs
2201.02 -2144.58 1354.473 -1975.27
2583.14 -2516.91 1589.625
-2318.2
2995.83 -2919.01 1843.588 -2688.57
3258.12 -3174.58 2004.996 -2923.95
3439.09 -3350.91 2116.364 -3086.36
Single Panel @Tilt angle = 0 degrees 2000
Wind Force(lbs)
1500
Force vs Wind Speed,Clear,positive
1000
500
Force vs Wind Speed,Clear,negative
0
‐500 0
‐1000
50
100
150
200
‐1500
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐2000
Wind Speed(mph)
Figure C3-13. Wind force analysis w.r.t different wind speeds at different tilt angle= 0 degrees for single panel
Single Panel @Tilt angle = 7.5 degrees 3000
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
2000
1000
Force vs Wind Speed,Clear,negative
0
‐1000
0
50
100
150
‐2000
‐3000
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C3-14. Wind force analysis w.r.t different wind speeds at different tilt angle= 7.5 degrees for single panel
179
Single Panel @ Tilt angle = 15 degrees 3000
Wind Force(lbs)
2000
Force vs Wind Speed,Clear,positive
1000
0
‐1000 0
50
100
150
200
‐2000
‐3000
Force vs Wind Speed,Clear,negative
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐4000
Wind Speed(mph)
Figure C3-15. Wind force analysis w.r.t different wind speeds at different tilt angle= 15 degrees for single panel
Single Panel @ Tilt angle = 30 degrees Wind Force(lbs)
4000
Force vs Wind Speed,Clear,positive
2000
Force vs Wind Speed,Clear,negative
0
0
50
100
150
‐2000
‐4000
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C3-16. Wind force analysis w.r.t different wind speeds at different tilt angle= 30 degrees for single panel
180
Case-2: For Effective wind area of 4 panels
Table C3-5. Wind force vs Wind speed calculations at different tilt angles for 4 panels
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 0 degrees
Wind
Clear
Obstructed
Speed,in
Positive Negative Positive Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
5417.89 -4966.4 2257.5 -5417.9
130
6358.5 -5828.62 2649.4 -6358.5
140
7374.35 -6759.82 3072.6 -7374.4
146
8019.99 -7351.65 3341.7
-8020
150
8465.46
-7760
3527.3 -8465.5
Wind
Speed,in
mph
120
130
140
146
150
Wind
Speed,in
mph
120
130
140
146
150
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 15 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces, forces, in
in lbs
lbs
in lbs
lbs
8126.84 -8578.329 5417.89 -9481.31
9537.75 -10067.62 6358.5
-11127.4
11061.5 -11676.06 7374.35 -12905.1
12030
-12698.31 8019.99
-14035
12698.2 -13403.64 8465.46 -14814.5
Wind
Speed,in
mph
120
130
140
146
150
181
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 7.5 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
7223.86 -6320.87 3611.93 -7675.35
8478
-7418.25
4239
-9007.87
9832.47 -8603.41 4916.24 -10447
10693.3 -9356.65 5346.66 -11361.6
11287.3 -9876.37 5643.64 -11992.7
Total Wind Force on 4 Panels (Zone 3+ Zone
2) at 30 degrees
Clear
Obstructed
Positive Negative
Positive
Negative
forces, forces, in forces, in forces, in
in lbs
lbs
lbs
lbs
11738.8 -11287.3 7223.856 -10384.3
13776.7 -13246.9 8477.998 -12187.1
15977.8 -15363.2 9832.471 -14134.2
17376.6 -16708.3 10693.31 -15371.6
18341.8 -17636.4 11287.27 -16225.5
4 Panels(2*2) @Tilt angle = 0 degrees Wind Force(lbs)
10000
Force vs Wind Speed,Clear,positive
5000
Force vs Wind Speed,Clear,negative
0
0
50
100
150
200
‐5000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐10000
Wind Speed(mph)
Figure C3-17. Wind force analysis w.r.t different wind speeds at different tilt angle= 0 degrees for 4 panels
4 Panels(2*2)@Tilt angle=7.5 degrees 15000
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
10000
5000
Force vs Wind Speed,Clear,negative
0
‐5000 0
50
100
150
‐10000
‐15000
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C3-18. Wind force analysis w.r.t different wind speeds at different tilt angle= 7.5 degrees for 4 panels
182
4 Panels(2*2)@Tilt angle=15 degrees Wind Force(lbs)
20000
Force vs Wind Speed,Clear,positive
10000
Force vs Wind Speed,Clear,negative
0
‐10000
0
50
‐20000
100
150
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C3-19. Wind force analysis w.r.t different wind speeds at different tilt angle= 15 degrees for 4 panels
Wind Force(lbs)
4 Panels(2*2)@Tilt angle=30 degrees 25000
20000
15000
10000
5000
0
‐5000 0
‐10000
‐15000
‐20000
Force vs Wind Speed,Clear,positive
Force vs Wind Speed,Clear,negative
50
100
150
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C3-20. Wind force analysis w.r.t different wind speeds at different tilt angle= 30 degrees for 4 panels
183
Case-3: For Effective wind area of 16 panels
Table C3-6. Wind force vs Wind speed calculations at different tilt angles for 16 panels
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 7.5 degrees
Wind
Clear
Obstructed
Speed,in
Positive
Negative
Positive
Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
43343.1 -37925.2 21671.6 -46052.1
130
50868 -44509.5 25434 -54047.2
140
58994.8 -51620.5 29497.4 -62682
146
64159.9 -56139.9 32079.9 -68169.9
150
67723.6 -59258.2 33861.8 -71956.4
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 0 degrees
Wind
Clear
Obstructed
Speed,in
Positive
Negative
Positive
Negative
mph
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
32507.4 -29798.4 13545
-32507
130
38151 -34971.7 15896
-38151
140
44246.1 -40558.9 18436
-44246
146
48119.9 -44109.9 20050
-48120
150
50792.7 -46560
21164
-50793
Wind
Speed,in
mph
120
130
140
146
150
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 15 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces,
forces, in
in lbs
lbs
in lbs
lbs
48761
-51469.97 32507.4 -56887.9
57226.5 -60405.73
38151
-66764.2
66369.2 -70056.35 44246.1 -77430.7
72179.9 -76189.86 48119.9 -84209.8
76189.1 -80421.83 50792.7 -88887.3
Wind
Speed,in
mph
120
130
140
146
150
184
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 30 degrees
Clear
Obstructed
Positive Negative
Positive
Negative
forces,
forces, in forces, in forces, in
in lbs
lbs
lbs
lbs
70432.6 -67723.6 43343.14 -62305.8
82660.5 -79481.2 50867.99 -73122.7
95866.6 -92179.4 58994.82 -84805.1
104260
-100250 64159.88 -92229.8
110051
-105818 67723.65 -97352.7
16 Panels(4*4)@Tilt angle = 0 degrees 60000
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
40000
20000
Force vs Wind Speed,Clear,negative
0
‐20000 0
50
100
150
200
‐40000
‐60000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C3-21. Wind force analysis w.r.t different wind speeds at different tilt angle= 0 degrees for 16 panels
16 Panels(4*4)@Tilt angle=7.5 degrees Wind Force(lbs)
100000
Force vs Wind Speed,Clear,positive
50000
Force vs Wind Speed,Clear,negative
0
0
50
100
150
200
‐50000
Force vs Wind Speed,Obstructed,positive
‐100000
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C3-22. Wind force analysis w.r.t different wind speeds at different tilt angle= 7.5 degrees for 16 panels
185
16 Panels(4*4)@Tilt angle=15 degrees Wind Force(lbs)
100000
Force vs Wind Speed,Clear,positive
50000
Force vs Wind Speed,Clear,negative
0
0
50
100
150
200
‐50000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐100000
Wind Speed(mph)
Figure C3-23. Wind force analysis w.r.t different wind speeds at different tilt angle= 15 degrees for 16 panels
16 Panels(4*4)@Tilt angle=30 degrees 150000
Force vs Wind Speed,Clear,positive
Wind Force(lbs)
100000
50000
Force vs Wind Speed,Clear,negative
0
‐50000 0
50
100
150
‐100000
‐150000
Wind Speed(mph)
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Figure C3-24. Wind force analysis w.r.t different wind speeds at different tilt angle= 30 degrees for 16 panels
186
Wind Load Analysis For Sloped Surfaces of North West 58th Street Landfill
Force vs Tilt angle graphs at different wind speeds:
Case-1: For Effective wind area of 1 Panel
Table C3-7. Wind force vs Tilt angle calculations at different wind speeds for single panel
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=150 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive
Negative
Positive
Negative
(or) Tilt
forces, in forces, in forces, in forces, in
angle,
lbs
lbs
lbs
lbs
in degrees
0
1208.296 -1141.17 537.0203
-1208.3
7.5
1611.061 -1409.68 805.5305 -1745.32
15
1812.444
-1946.7 1208.296 -2148.08
30
2617.974 -2550.85 1611.061 -2349.46
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=146 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive
Negative
Positive
Negative
(or) Tilt
forces, in forces, in forces, in forces, in
angle,
lbs
lbs
lbs
lbs
in degrees
0
1144.713 -1081.12 508.7611 -1144.71
7.5
1526.283
-1335.5 763.1417 -1653.47
15
1717.069 -1844.26 1144.713 -2035.04
30
2480.21 -2416.62 1526.283 -2225.83
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=140 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in forces, forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
1052.56 -994.084 467.8044 -1052.56
7.5
1403.413 -1227.99 701.7066 -1520.36
15
1578.84 -1695.79
1052.56 -1871.22
30
2280.546 -2222.07 1403.413 -2046.64
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=130 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in forces, forces, in forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
907.5643 -857.144 403.3619 -907.564
7.5
1210.086 -1058.83 605.0429 -1310.93
15
1361.347 -1462.19 907.5643 -1613.45
30
1966.389 -1915.97 1210.086 -1764.71
187
For Effective wind area of 1 Panel,in sq.ft
Wind Speed=120 mph
Clear
Obstructed
Angle of Panels
Placement (or)
Positive
Negative
Positive
Negative
Tilt angle,
forces, in forces, in forces, in forces, in
in degrees
lbs
lbs
lbs
lbs
0
773.3093 -730.348
343.693 -773.309
7.5
1031.079 -902.194
515.5395
-1117
15
1159.964 -1245.89
773.3093 -1374.77
30
1675.503 -1632.54
1031.079 -1503.66
Single Panel
Wind Force(lbs)
3000
2500
2000
Clear,positive(150 mph)
1500
Clear,positive(146 mph)
1000
Clear,positive(140 mph)
500
Clear,positive(130 mph)
0
Clear,positive(120 mph)
0
10
20
30
40
Angle of Panels Placement(degrees)
Figure C3-25. Positive wind force analysis at different wind speeds for clear wind flow
188
Wind Force(lbs)
Single Panel
1800
1600
1400
1200
1000
800
600
400
200
0
Obstructed,positive(150 mph)
Obstructed,positive(146 mph)
Obstructed,positive(140 mph)
Obstructed,positive(130 mph)
Obstructed,positive(120 mph)
0
10
20
30
40
Angle of Panels Placement(degrees)
Figure C3-26. Positive wind force analysis at different wind speeds for obstructed wind flow
Single Panel
0
Wind Force(lbs)
‐500 0
10
20
30
40
Clear,negative(150 mph)
‐1000
Clear,negative(146 mph)
‐1500
Clear,negative(140 mph)
‐2000
Clear,negative(130 mph)
Clear,negative(120 mph)
‐2500
‐3000
Angle of Panels Placement(degrees)
Figure C3-27. Negative wind force analysis at different wind speeds for clear wind flow
189
Single Panel
0
0
10
20
30
Wind Force(lbs)
40
Obstructed,negative(150 mph)
‐500
Obstructed,negative(146 mph)
‐1000
Obstructed,negative(140 mph)
‐1500
Obstructed,negative(130 mph)
‐2000
‐2500
Obstructed,negative(120 mph)
Angle of Panels Placement(degrees)
Figure C3-28. Negative wind force analysis at different wind speeds for obstructed wind flow
190
Case-2: For Effective wind area of 4 Panels
Table C3-8. Wind force vs Tilt angle calculations at different wind speeds for 4 panels
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=150 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
6444.244 -5907.22 2685.102 -6444.24
7.5
8592.325 -7518.28 4296.163 -9129.35
15
9666.366 -10203.4 6444.244 -11277.4
30
13962.53 -13425.5 8592.325 -12351.5
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=146 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
6105.133 -5596.37 2543.806 -6105.13
7.5
8140.178 -7122.66 4070.089 -8648.94
15
9157.7
-9666.46 6105.133
-10684
30
13227.79
-12719
8140.178 -11701.5
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=140 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
5613.652 -5145.85 2339.022 -5613.65
7.5
7484.87 -6549.26 3742.435 -7952.67
15
8420.479 -8888.28 5613.652 -9823.89
30
12162.91 -11695.1 7484.87 -10759.5
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=130 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
4840.343 -4436.98 2016.81 -4840.34
7.5
6453.791 -5647.07 3226.895 -6857.15
15
7260.515 -7663.88 4840.343 -8470.6
30
10487.41
-10084
6453.791 -9277.32
191
For Effective wind area of 4(2*2) Panels, in sq.ft
Wind Speed=120 mph
Clear
Obstructed
Angle of Panels
Placement (or)
Positive
Negative
Positive
Negative
Tilt angle,
forces, in forces, in forces, in forces, in
in degrees
lbs
lbs
lbs
lbs
0
4124.316 -3780.62 1718.465 -4124.32
7.5
5499.088
-4811.7
2749.544 -5842.78
15
6186.474 -6530.17 4124.316 -7217.55
30
8936.018 -8592.33 5499.088 -7904.94
4 Panels(2*2)
16000
Wind Force(lbs)
14000
12000
10000
Clear,positive(150 mph)
8000
Clear,positive(146 mph)
6000
Clear,positive(140 mph)
4000
Clear,positive(130 mph)
2000
Clear,positive(120 mph)
0
0
10
20
30
40
Angle of Panels Placement(degrees)
Figure C3-29. Positive wind force analysis at different wind speeds for clear wind flow
192
4 Panels(2*2)
Wind Force(lbs)
10000
8000
Obstructed,positive(150 mph)
6000
Obstructed,positive(146 mph)
4000
Obstructed,positive(140 mph)
2000
Obstructed,positive(130 mph)
0
0
5
10
15
20
25
30
35
Obstructed,positive(120 mph)
Angle of Panels Placement(degrees)
Figure C3-30. Positive wind force analysis at different wind speeds for obstructed wind flow
4 Panels(2*2)
0
Wind Force(lbs)
0
5
10
15
20
25
30
35
Clear,negative(150 mph)
‐5000
Clear,negative(146 mph)
Clear,negative(140 mph)
‐10000
Clear,negative(130 mph)
Clear,negative(120 mph)
‐15000
Angle of Panels Placement(degrees)
Figure C3-31. Negative wind force analysis at different wind speeds for clear wind flow
193
4 Panels(2*2)
0
Wind Force(lbs)
‐2000 0
10
20
30
40
Obstructed,negative(150 mph)
‐4000
Obstructed,negative(146 mph)
‐6000
‐8000
Obstructed,negative(140 mph)
‐10000
Obstructed,negative(130 mph)
‐12000
Obstructed,negative(120 mph)
‐14000
Angle of Panels Placement(degrees)
Figure C3-32. Negative wind force analysis at different wind speeds for obstructed wind flow
194
Case-3: For Effective wind area of 16 panels
Table C3-9. Wind force vs Tilt angle calculations at different wind speeds for 16 panels
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=150 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces, forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
38665.46 -35443.3 16110.61 -38665.5
7.5
51553.95 -45109.7 25776.98 -54776.1
15
57998.19 -61220.3 38665.46 -67664.6
30
83775.17
-80553 51553.95 -74108.8
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=146 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces, forces, in forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
36630.8 -33578.2 15262.83 -36630.8
7.5
48841.07 -42735.9 24420.53 -51893.6
15
54946.2 -57998.8
36630.8 -64103.9
30
79366.73 -76314.2 48841.07
-70209
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=140 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
33681.91 -30875.1 14034.13 -33681.9
7.5
44909.22 -39295.6 22454.61
-47716
15
50522.87 -53329.7 33681.91 -58943.4
30
72977.48 -70170.7 44909.22
-64557
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=130 mph
Angle of
Panels
Clear
Obstructed
Placement
Positive Negative Positive Negative
(or) Tilt
forces, in
forces,
forces, in
forces,
angle,
lbs
in lbs
lbs
in lbs
in degrees
0
29042.06 -26621.9 12100.86 -29042.1
7.5
38722.75 -33882.4 19361.37 -41142.9
15
43563.09 -45983.3 29042.06 -50823.6
30
62924.46 -60504.3 38722.75 -55663.9
195
For Effective wind area of 16(4*4) Panels, in sq.ft
Wind Speed=120 mph
Clear
Obstructed
Angle of Panels
Placement (or) Tilt
Positive
Negative
Positive
Negative
angle,
in
forces, in
forces, in
forces, in
forces, in
degrees
lbs
lbs
lbs
lbs
0
24745.9
-22683.7
10310.79
-24745.9
7.5
32994.53
-28870.2
16497.26
-35056.7
15
37118.84
-39181
24745.9
-43305.3
30
53616.11
-51554
32994.53
-47429.6
16 Panels(4*4)
wind Force(lbs)
100000
80000
Clear,positive(150 mph)
60000
Clear,positive(146 mph)
40000
Clear,positive(140 mph)
20000
Clear,positive(130 mph)
0
0
10
20
30
40
Angle of Panels Placement(degrees)
196
Clear,positive(120 mph)
Figure C3-33. Positive wind force analysis at different wind speeds for clear wind flow
16 Panels(4*4)
Wind Force(lbs)
60000
50000
Obstructed,positive(150 mph)
40000
Obstructed,positive(146 mph)
30000
Obstructed,positive(140 mph)
20000
10000
Obstructed,positive(130 mph)
0
Obstructed,positive(120 mph)
0
10
20
30
40
Angle of Panels Placement(degrees)
Figure C3-34. Positive wind force analysis at different wind speeds for obstructed wind flow
197
16 Panels(4*4)
Wind Force(lbs)
0
‐20000
0
10
20
30
40
Clear,negative(150 mph)
‐40000
Clear,negative(146 mph)
‐60000
Clear,negative(140 mph)
Clear,negative(130 mph)
‐80000
Clear,negative(120 mph)
‐100000
Angle of Panels Placement(degrees)
Figure C3-35. Negative wind force analysis at different wind speeds for clear wind flow
16 Panels(4*4)
0
Wind Force(lbs)
‐10000 0
5
10
15
20
25
‐20000
30
35
Obstructed,negative(150 mph)
‐30000
Obstructed,negative(146 mph)
‐40000
‐50000
Obstructed,negative(140 mph)
‐60000
Obstructed,negative(130 mph)
‐70000
‐80000
Angle of Panels Placement(degrees)
198
Obstructed,negative(120 mph)
Figure C3-36. Negative wind force analysis at different wind speeds for obstructed wind flow
Force vs Wind speed graphs at different wind speeds:
Case-1: For Effective wind area of 1panel
Table C3-10. Wind force vs Wind speed calculations at different tilt angles for 1 panel
Wind
Speed,in
mph
120
130
140
146
Total Wind Force on 1 Panel (Zone 3) at 0
degrees
Clear
Obstructed
Positive Negative Positive Negative
forces, forces, in forces, forces, in
in lbs
lbs
in lbs
lbs
773.309 -730.348 343.69
-773.31
-907.56
907.564 -857.144 403.36
1052.56 -994.084
467.8
-1052.6
1144.71 -1081.12 508.76
-1144.7
Wind
Speed,in
mph
120
130
140
146
199
Total Wind Force on 1 Panel (Zone 3) at
7.5 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces, forces, in forces, forces, in
in lbs
lbs
in lbs
lbs
1031.08 -902.194 515.54
-1117
1210.09 -1058.83 605.043 -1310.93
1403.41 -1227.99 701.707 -1520.36
1526.28 -1335.5 763.142 -1653.47
150
Wind
Speed,in
mph
120
130
140
146
150
1208.3
-1141.17
537.02
-1208.3
150
Total Wind Force on 1 Panel (Zone 3) at 15
degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces,
forces, in
in lbs
lbs
in lbs
lbs
1159.96 -1245.887 773.309
-1374.77
1361.35 -1462.187 907.564
-1613.45
1578.84 -1695.791 1052.56
-1871.22
1717.07 -1844.259 1144.71
-2035.04
1812.44 -1946.699 1208.3
-2148.08
Wind
Speed,in
mph
120
130
140
146
150
1611.06
-1409.68
805.53
-1745.32
Total Wind Force on 1 Panel (Zone 3) at 30
degrees
Clear
Obstructed
Positive Negative
Positive
Negative
forces,
forces, in forces, in forces, in
in lbs
lbs
lbs
lbs
1675.5
-1632.54 1031.079 -1503.66
1966.39 -1915.97 1210.086 -1764.71
2280.55 -2222.07 1403.413 -2046.64
2480.21 -2416.62 1526.283 -2225.83
2617.97 -2550.85 1611.061 -2349.46
Single Panel @Tilt angle = 0 degrees 1500
Wind Force(lbs)
1000
Force vs Wind Speed,Clear,positive
500
Force vs Wind Speed,Clear,negative
0
‐500
0
50
100
150
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐1000
‐1500
200
Wind Speed(mph)
Figure C3-37. Wind force analysis w.r.t different wind speeds at different tilt angle= 0 degrees for 1 panel
200
Single Panel @Tilt angle = 7.5 degrees 2000
Wind Force(lbs)
1500
Force vs Wind Speed,Clear,positive
1000
500
Force vs Wind Speed,Clear,negative
0
‐500 0
50
100
150
200
‐1000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐1500
‐2000
Wind Speed(mph)
Figure C3-38. Wind force analysis w.r.t different wind speeds at different tilt angle= 7.5 degrees for 1 panel
Single Panel @ Tilt angle = 15 degrees Wind Force(lbs)
3000
Force vs Wind Speed,Clear,positive
2000
1000
Force vs Wind Speed,Clear,negative
0
‐1000 0
50
100
150
‐2000
‐3000
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
201
Figure C3-39. Wind force analysis w.r.t different wind speeds at different tilt angle= 15 degrees for 1 panel
Single Panel @ Tilt angle = 30 degrees 3000
Wind Force(lbs)
2000
Force vs Wind Speed,Clear,positive
1000
Force vs Wind Speed,Clear,negative
0
‐1000
0
50
100
150
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐2000
‐3000
200
Wind Speed(mph)
Figure C3-40. Wind force analysis w.r.t different wind speeds at different tilt angle= 30 degrees for 1 panel
202
Case-1: For Effective wind area of 4 panels
Table C3-11. Wind force vs Wind speed calculations at different tilt angles for 4 panels
Wind
Speed,in
mph
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 0 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
Wind
Speed,in
mph
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 7.5 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces,
forces,
forces,
in lbs
in lbs
in lbs
in lbs
120
4124.32
-3780.62
1718.5
-4124.3
120
5499.09
-4811.7
2749.54
-5842.78
130
140
4840.34
5613.65
-4436.98
-5145.85
2016.8
2339
-4840.3
-5613.7
130
140
6453.79
7484.87
-5647.07
-6549.26
3226.9
3742.43
-6857.15
-7952.67
146
150
6105.13
6444.24
-5596.37
-5907.22
2543.8
2685.1
-6105.1
-6444.2
146
150
8140.18
8592.33
-7122.66
-7518.28
4070.09
4296.16
-8648.94
-9129.35
Wind
Speed,in
mph
120
130
140
146
150
Total Wind Force on 4 Panels (Zone 3+
Zone 2) at 15 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces,
forces, in
in lbs
lbs
in lbs
lbs
6186.47 -6530.167 4124.32 -7217.55
7260.51 -7663.877 4840.34
-8470.6
8420.48 -8888.283 5613.65 -9823.89
9157.7 -9666.461 6105.13
-10684
9666.37 -10203.39 6444.24 -11277.4
Wind
Speed,in
mph
120
130
140
146
150
203
Total Wind Force on 4 Panels (Zone 3+ Zone
2) at 30 degrees
Clear
Obstructed
Positive Negative
Positive
Negative
forces,
forces, in forces, in forces, in
in lbs
lbs
lbs
lbs
8936.02 -8592.33 5499.088 -7904.94
10487.4
-10084
6453.791 -9277.32
12162.9 -11695.1
7484.87
-10759.5
13227.8
-12719
8140.178 -11701.5
13962.5 -13425.5 8592.325 -12351.5
4 Panels(2*2) @Tilt angle = 0 degrees 8000
Wind Force(lbs)
6000
Force vs Wind Speed,Clear,positive
4000
2000
Force vs Wind Speed,Clear,negative
0
‐2000 0
50
100
150
200
‐4000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐6000
‐8000
Wind Speed(mph)
Figure C3-41. Wind force analysis w.r.t different wind speeds at different tilt angle= 0 degrees for 4 panels
4 Panels(2*2)@Tilt angle=7.5 degrees Wind Force(lbs)
10000
Force vs Wind Speed,Clear,positive
5000
0
‐5000
0
50
100
150
Force vs Wind Speed,Obstructed,positive
‐10000
‐15000
200
Force vs Wind Speed,Clear,negative
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C3-42. Wind force analysis w.r.t different wind speeds at different tilt angle= 7.5 degrees for 4 panels
204
4 Panels(2*2)@Tilt angle=15 degrees Wind Force(lbs)
15000
Force vs Wind Speed,Clear,positive
10000
5000
Force vs Wind Speed,Clear,negative
0
‐5000 0
50
100
150
200
‐10000
‐15000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C3-43. Wind force analysis w.r.t different wind speeds at different tilt angle= 15 degrees for 4 panels
4 Panels(2*2)@Tilt angle=30 degrees 20000
Wind Force(lbs)
15000
Force vs Wind Speed,Clear,positive
10000
Force vs Wind Speed,Clear,negative
5000
0
‐5000 0
50
100
150
‐10000
‐15000
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C3-45. Wind force analysis w.r.t different wind speeds at different tilt angle= 30 degrees for 4 panels
205
Case-1: For Effective wind area of 16 panels
Table C3-12. Wind force vs Wind speed calculations at different tilt angles for 16 panels
Wind
Speed,in
mph
120
130
140
146
150
Wind
Speed,in
mph
120
130
140
146
150
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 0 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces,
forces, in
in lbs
lbs
in lbs
lbs
24745.9 -22683.7
10311
-24746
29042.1 -26621.9
12101
-29042
33681.9 -30875.1
14034
-33682
36630.8 -33578.2
15263
-36631
38665.5 -35443.3
16111
-38665
Wind
Speed,in
mph
120
130
140
146
150
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 15 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces,
forces, in
in lbs
lbs
in lbs
lbs
37118.8
-39181
24745.9 -43305.3
43563.1 -45983.26 29042.1 -50823.6
50522.9 -53329.7 33681.9 -58943.4
54946.2 -57998.77 36630.8 -64103.9
57998.2 -61220.32 38665.5 -67664.6
Wind
Speed,in
mph
120
130
140
146
150
206
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 7.5 degrees
Clear
Obstructed
Positive Negative Positive Negative
forces,
forces, in
forces,
forces, in
in lbs
lbs
in lbs
lbs
32994.5 -28870.2 16497.3 -35056.7
38722.7 -33882.4 19361.4 -41142.9
44909.2 -39295.6 22454.6
-47716
48841.1 -42735.9 24420.5 -51893.6
51554
-45109.7
25777
-54776.1
Total Wind Force on 16 Panels (Zone 3+
Zone 2+ Zone 1) at 30 degrees
Clear
Obstructed
Positive Negative
Positive
Negative
forces,
forces, in forces, in forces, in
in lbs
lbs
lbs
lbs
53616.1
-51554
32994.53 -47429.6
62924.5 -60504.3 38722.75 -55663.9
72977.5 -70170.7 44909.22
-64557
79366.7 -76314.2 48841.07
-70209
83775.2
-80553
51553.95 -74108.8
Wind Force(lbs)
16 Panels(4*4)@Tilt angle = 0 degrees 50000
40000
30000
20000
10000
0
‐10000
‐20000 0
‐30000
‐40000
‐50000
Force vs Wind Speed,Clear,positive
Force vs Wind Speed,Clear,negative
50
100
150
200
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C3-46. Wind force analysis w.r.t different wind speeds at different tilt angle= 0 degrees for 16 panels
16 Panels(4*4)@Tilt angle=7.5 degrees 60000
Wind Force(lbs)
40000
Force vs Wind Speed,Clear,positive
20000
0
‐20000 0
50
100
150
‐40000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐60000
‐80000
200
Force vs Wind Speed,Clear,negative
Wind Speed(mph)
Figure C3-47. Wind force analysis w.r.t different wind speeds at different tilt angle= 7.5 degrees for 16 panels
207
16 Panels(4*4)@Tilt angle=15 degrees 80000
Wind Force(lbs)
60000
Force vs Wind Speed,Clear,positive
40000
20000
Force vs Wind Speed,Clear,negative
0
‐20000 0
‐40000
50
100
150
200
‐60000
Force vs Wind Speed,Obstructed,positive
Force vs Wind Speed,Obstructed,negative
‐80000
Wind Speed(mph)
Figure C3-48. Wind force analysis w.r.t different wind speeds at different tilt angle= 15 degrees for 16 panels
16 Panels(4*4)@Tilt angle=30 degrees Wind Force(lbs)
100000
Force vs Wind Speed,Clear,positive
50000
Force vs Wind Speed,Clear,negative
0
0
50
100
150
200
‐50000
Force vs Wind Speed,Obstructed,positive
‐100000
Force vs Wind Speed,Obstructed,negative
Wind Speed(mph)
Figure C3-49. Wind force analysis w.r.t different wind speeds at different tilt angle= 30 degrees for 16 pa
208
209