Montgomery College New
Science Center
Energy Efficient System Design:
Geothermal System Coupled with
Chilled Beams and DOAS
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Presentation Material:
Building Overview
Redesign Goals
Current Mechanical System
Mechanical System Redesign
Lighting Redesign
Acoustic Impact
Energy Savings
Cost Analysis
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
•Located on Montgomery College Rockville Maryland Campus
Presentation Material:
Building Overview
•Four Stories
•140,700 Square Feet
Redesign Goals
•Direct Addition to Science East
Current Mechanical System
•Bridge Connected to Science West
Mechanical System Redesign
Lighting Redesign
•Consists of Laboratories, Classrooms, and Offices
Acoustic Impact
• Four Story Atrium
Energy Savings
•Roof Observatory with power switch sliding roof
Cost Analysis
•Exterior Amphitheatre
Conclusions
•Water Retention Pond
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
System Redesign Goals:
Presentation Material:
Building Overview
Redesign Goals
Current Mechanical System
Mechanical System Redesign
Lighting Redesign
Acoustic Impact
Energy Savings
Cost Analysis
•Energy Efficiency
•Environmental Impact
Original Design Goals:
•Energy Efficiency
•Control Laboratory
Contaminants
•Anticipated Expansion
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Current Central Chilled Water System:
Presentation Material:
System in Place:
Building Overview
•225 Ton Chillers with VFD
Redesign Goals
•Cooling Tower
Current Mechanical System
•Two Condenser Pumps
Mechanical System Redesign
Lighting Redesign
Original New Design:
•Two 305 Ton Centrifugal Chillers
Acoustic Impact
Energy Savings
•Two induced draft-cross flow Cooling Towers arranged to
share a basin with VFDs
Cost Analysis
Conclusions
•Two Primary & Secondary Pumps with VFDs
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Current Central Hot Water System:
Presentation Material:
•Two 3 Million BTU 87% operating efficiency Boilers
Building Overview
Redesign Goals
•Two Distribution & Campus Distribution Pumps
Current Mechanical System
•No Boiler Pumps
Mechanical System Redesign
Lighting Redesign
Acoustic Impact
Energy Savings
Cost Analysis
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Current Central Air Handling System:
•Two VAV Rooftop Units manifolded together by a common discharge plenum
Presentation Material:
Building Overview
Redesign Goals
•Dual Supply Fans
•Isolation Dampers to isolate one unit from the rest of the system
Current Mechanical System
•No Return Fan
Mechanical System Redesign
•Return Air Damper maintains building pressure
Lighting Redesign
•Heating and Cooling Coils
Acoustic Impact
Energy Savings
Cost Analysis
•Heat Recovery Coil
•Local Reheat Coils at Rooms
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Current Central Exhaust System:
Presentation Material:
Building Overview
Redesign Goals
Current Mechanical System
Mechanical System Redesign
Lighting Redesign
Acoustic Impact
Energy Savings
•Four high plume Exhaust Fans connected by common plenum
•Maintain Negative pressure in the Exhaust Plenum and
Laboratories
•Constant Volume/fan; Variable Volume for the building
•Make-up Air Damper in Exhaust Plenum to maintain a constant
exhaust flow rate
•Dampers within plenum normally open that maintains remote
duct static pressure
Cost Analysis
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Geothermal Systems:
Presentation Material:
Building Overview
Redesign Goals
•Earth’s solar energy is absorbed into the ground in the form of heat energy
•Moves Heat Energy
•Open loop systems use a water source as the heat sink
•Utilizes a heat sink to take or expel heat energy
•Closed loop systems use the constant ground temperature as a heat sink
•Open and closed loop system types
Current Mechanical System
Mechanical System Redesign
Lighting Redesign
Acoustic Impact
Energy Savings
Cost Analysis
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Geothermal Systems:
Presentation Material:
•Transfers energy between the heat sink and the building
Building Overview
•Works in place of a the cooling tower & boiler in a typical HVAC system
Redesign Goals
•Variable flow is ideal to decrease the pumping power
Current Mechanical System
Mechanical System Redesign
•Reduces the amount of electricity & fossil fuel needed
Lighting Redesign
Acoustic Impact
Energy Savings
Cost Analysis
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
•Passive chilled beams induce
current through natural convection
Chilled Beams:
Presentation Material:
Building Overview
Redesign Goals
Current Mechanical System
Mechanical System Redesign
Lighting Redesign
Acoustic Impact
Energy Savings
Cost Analysis
Conclusions
•Low investment costs
•Air passes over cooled coils and
drops into the room
•High Cooling Capacities
•Available as passive or active
•Coupled with a geothermal system: become a water- to – water system ,
increasing the energy efficiency
•Warm air rises into the beam to
be cooled and then redistributed
into the room
•Active chilled beams provide
ventilation air through small air jets in
addition to the induced air flow
•Recessed in or hung from the ceiling in place of a diffuser
•Water pumped to the chilled beam in the room to cool the air locally
•Natural convection and ventilation
air induce airflow over the coils
•Allows the HVAC system to decouple the ventilation and the humidity
requirements from the sensible heating and cooling requirements
•Air is then cooled and diffused into
the room
•Possible noise problems
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Laboratory and Classroom Mechanical System Redesign:
Presentation Material:
Building Overview
Redesign Goals
Current Mechanical System
Mechanical System Redesign
•Replaces the original boilers, chillers, and cooling towers, with
water to water heat pumps and water to air heat pumps.
•Four water to water heat pumps are provided for the
laboratories and classrooms
•One additional water to water heat pump for redundancy and
simultaneous heating and cooling conditions
Lighting Redesign
•The water is supplied to and from the pond to a heat exchanger
Acoustic Impact
•The geothermal system acts like a closed loop system taking water
to and from the heat exchanger to the water to water heat
pump
Energy Savings
Cost Analysis
Conclusions
•The water to water heat pump water is distributed to the
variable flow active chilled beams
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Labs/CB WW Heat Pumps
Heating
Cooling
MBH
1,399
1,071
TONS
117
89
UNIT MBH
350
393
# OF UNITS
4
3
COP
4.08
5.22
EER
13.92
17.80
GPM
84
84
Laboratory and Classroom Mechanical System Redesign:
Presentation Material:
Building Overview
Redesign Goals
•The heat exchanger that transfers the heat energy from the water retention
pond, supplies the water to the DOAS heat pump
•Ventilation air is supplied to the laboratory and classroom active chilled
beams by the DOAS heat pump
Current Mechanical System
•The DOAS heat pump provides any necessary dehumidification
Mechanical System Redesign
•The water is condensed out of the air until 55% RH is reached and then reheated
Lighting Redesign
Acoustic Impact
•All air from the laboratories is exhausted from the building after passing
over the enthalpy wheel
Energy Savings
Cost Analysis
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Lab/CB DOAS HP
Heating
Cooling
MBH
1,203
8,154
TONS
100
680
CFM
101,255
101,255
UNIT MBH
406
916
# OF UNITS
3
9
UNIT CFM
12,400
12,400
# OF UNITS
9
9
COP
4.30
5.33
EER
14.67
18.20
Office Mechanical System Redesign:
Presentation Material:
Building Overview
Redesign Goals
Current Mechanical System
Mechanical System Redesign
Lighting Redesign
Acoustic Impact
Energy Savings
Cost Analysis
Conclusions
Office
Rooftop HP
Heating
•Water is supplied from the heat exchanger to the rooftop
heat pump where the heat energy is transferred to the air that
is then supplied to the offices
Cooling
•The rooftop heat pump supplies air to the offices at 52⁰F
through a VAV box and reheat coil
•The water for the reheat coils is provided by the
water-to-water heat pumps
•Air is returned from the offices to the rooftop heat pump
decrease the amount of air conditioning
•Dehumidification is completed in the rooftop heat pump
similar to the DOAS heat pump but without the help of the
enthalpy wheel
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
BTUH
196,52
1
405,64
0
TON
S
16
34
CFM
15,62
7
15,62
7
UNIT
MBH
181
# OF
UNITS
2
UNIT
CFM
8,000
# OF
UNITS
2
COP
EER
3.40
11.60
237
2
8,000
2
4.25
14.50
Energy Efficient Replacement Fixtures:
Presentation Material:
Lighting Redesign
Original Lighting
Heating
(boilers etc.)
Cooling
(chillers etc.)
Fans, pumps
and controls
Lights
Equip.
8445.139
8406.94
13749.672
13885.029
310949.906
310998.094
1247.095
1432.732
4773.785
4773.785
Building Overview
Redesign Goals
Earth Friendly Troffers
• Up to 88% efficiency
Current Mechanical System
• Recessed 2’x4’
Mechanical System Redesign
Lighting Redesign
• Power Density: 0.7 W/ft2
Acoustic Impact
• Highly reflective matte white power coating
Energy Savings
• Engineered louvers
Cost Analysis
• 3” Baffle element that illuminates while reducing glare
Conclusions
• Occupancy Sensors
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Lightings Schedules within IES Model:
Presentation Material:
•Occupancy Type
Building Overview
•Anticipated Typical Weekday Usage
Redesign Goals
•Anticipated Typical Weekend Usage
Current Mechanical System
Mechanical System Redesign
Lighting Redesign
Acoustic Impact
Energy Savings
Cost Analysis
Office Weekday Lighting Schedule
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Lighting Redesign Energy Savings:
Presentation Material:
Lighting Redesign Energy Comparison
Savings in:
339,600
Redesign Goals
339,500
Current Mechanical System
339,400
•Cooling Energy and Load
339,300
•HVAC Equipment Energy and Load
MMBTU
Building Overview
Mechanical System Redesign
Lighting Redesign
•Illuminance Energy
339,200
Acoustic Impact
339,100
Energy Savings
339,000
Cost Analysis
Lighting Redesign
Original Lighting
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Room Reverberation Time:
Presentation Material:
Original Acoustical Design
Classrooms, Laboratories, and Offices should have a reverberation time between
0.7 and 1.1 seconds
Building Overview
Redesign Goals
Current Mechanical System
Mechanical System Redesign
Lighting Redesign
Acoustic Impact
T60 at 500 HZ
T60 at 1000 HZ
Classroom
Laboratory
Office
0.66 seconds
0.66 seconds
0.46 seconds
0.65seconds
0.65 seconds
0.34 seconds
Recommendations:
•Some of the walls changed from the single layer of gypsum board to a double layer
Recommended Acoustical Design
•Acoustical Ceiling Tile replaced with Armstrong Suspended Ceiling
•Carpet in Offices changed to Epoxy Terrazzo
Energy Savings
Cost Analysis
ROOM
•Light decorative Velour added to Large Offices
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
ROOM
T60 at 500 HZ
T60 at 1000 HZ
Classroom
Laboratory
Office
0.77 seconds
0.78 seconds
0.73 seconds
0.70 seconds
0.70 seconds
0.71 seconds
Classrooms
Laboratories
Private Offices
Presentation Material:
Building Overview
Redesign Goals
Chilled Beam Acoustics:
NC Rating
25-30
35-40
30-35
•Static Pressure should never exceed 0.4” w.c.
•Classrooms and offices need less ventilation air than the
laboratories and therefore have smaller flow rates
Current Mechanical System
Mechanical System Redesign
Lighting Redesign
Acoustic Impact
Energy Savings
Cost Analysis
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Energy Savings:
Presentation Material:
Building Overview
Redesign Goals
Current Mechanical System
Mechanical System Redesign
Lighting Redesign
Acoustic Impact
Energy Savings
Cost Analysis
Redesign
System Component MMBTU
Nat gas
88
Electricity
5,404
Chilled Beam HP
507
(heating)
Office Reheat
488
Chilled Beam HP (cooling)
953
DOAS HP
2,037
Office Heat Pump
546
Pumps
9,548
Lights
1,248
Total energy 20,817
•27.75% Energy Savings over
the original design
kwh
25,674
1,583,702
148,496
142,947
279,242
596,999
159,962
2,798,240
365,797
6,101,060
MMBTU
5,726
Original Design
kwh
System Component
Fans, Controls, Plug,
1,678,087
Misc.
9,239
2,707,802
Direct Acting Heater
7,273
2,131,514
Boilers and Chillers
5,142
1432
28,811
1,506,947
419,695
8,444,045
Pumps
Lights
Total Original Energy
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Energy Comparison
28,811
M
M
B
T
U
•energy required for the heat
pumps is about half the energy
needed for the boilers and
chillers
20,817
•Needed Reheat was reduced
almost 90%
Total Redesign Energy
Total Original Energy
•Lighting energy was reduced
by the lighting redesign
•Saves 2,342,986 kilowatts a
year
Energy Savings:
Presentation Material:
Building Overview
Redesign Goals
Current Mechanical System
Mechanical System Redesign
Lighting Redesign
Acoustic Impact
Original System Design
MMBTU
therms
boilers
2,949
29,493
Total Natural Gas
2,949
29,493
Energy Rates:
•$1.54 per therm
•$0.1321 per kilowatt hour
Comparison:
•Original design:
$1,406,706/yr
•Majority of cost is attributed to direct acting heaters due to local
reheat
•Redesign:
$805,257/yr
•Majority of cost is attributed to the pumps since the system is
predominately hydronic
Energy Savings
Cost Analysis
•Resultant Savings:
$601,449/yr from original design
$1,148,501/ yr from the Baseline
Conclusions
THE PENNSYLVANIA STATE UNIVERSITY
Total Energy Cost
MMBTU
4,324
9,239
3,617
5,142
2,108
1,433
25,863
kwh
1,267,280
2,707,690
1,060,092
1,506,884
617,925
419,896
7,579,767
$1.54/therm
$1,349.33
MMBTU
5,404
507
488
953
2,037
546
9,548
1,248
20,817
$0.1321/kwh
$209,207.06
$19,616.27
$18,883.34
$36,887.90
$78,863.56
$21,131.01
$369,647.55
$48,321.81
$803,907.83
$0.1321/kwh
$167,407.66
$357,685.87
$140,038.12
$199,059.40
$81,627.95
$55,468.24
$1,001,287.24
$1,046,706.36
Total Energy Cost
Energy Costs/year
System Redesign
$1,200,000.00
$1,000,000.00
$800,000.00
$600,000.00
$400,000.00
$0.00
APRIL 15TH 2009
System Redesign
MMBTU
therms
Nat gas
88
876
Electricity
Chilled Beam HP (heating)
Office Reheat
Chilled Beam HP (cooling)
DOAS HP
Office Heat Pump
Pumps
Lights
Total energy
$200,000.00
•Redesign saves 42.76% over the original design
AMY LEVENTRY
chillers
direct acting heaters
fan
pump
equipment
Lights
Total Electric
$1.54/therm
$45,419.11
$45,419.11
Original Design
$805,257
$1,046,706
kwh
1,583,702
148,496
142,947
279,242
596,999
159,962
2,798,240
365,797
6,076,262
$805,257.16
LEED Assessment:
Category
•Increased the Energy and Atmosphere Category by 2 point
Presentation Material:
Building Overview
•Gained the 2 points in the Optimize Energy Performance Credit
Redesign Goals
•Increase the credit from 8/10 points to 10/10 points available
Current Mechanical System
•The Original Design was an estimated 28% energy cost savings
over the ASHRAE 90.1 Baseline Building
Mechanical System Redesign
Lighting Redesign
•35% Energy Savings must be reached to receive 10 out of 10 of the
Optimize Energy Performance Credit
Acoustic Impact
Energy Savings
•The Redesign is an estimated 58.78% energy cost savings over
the ASHRAE 90.1 Baseline Building
Cost Analysis
•This would most likely qualify for an additional Innovation and
Design Credit
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Sustainable Site
Water Efficiency
Energy and Atmosphere
Materials and Resources
Indoor Environmental Quality
Innovation and Design
Total
Category
Sustainable Site
Water Efficiency
Energy and Atmosphere
Materials and Resources
Indoor Environmental Quality
Innovation and Design
Total
Points
Anticipated
8
3
12
4
13
2
42
Possible
Points
14
5
17
13
15
5
69
Points
Anticipated
8
3
14
4
13
2
44
Possible
Points
14
5
17
13
15
5
69
Initial Cost Comparison:
Presentation Material:
•Original Design HVAC Initial Cost:
•$73.43/ square foot
$10,332,198
•Redesign HVAC Initial Cost:
•$91.17/ square foot
$12,828240
Mechanical System Redesign
•Increased Cost:
$2,496,042
Lighting Redesign
•It would take 4.15 years for the energy savings to overcome the
increased initial costs of the redesigned system over the original
design
Building Overview
Redesign Goals
Current Mechanical System
Acoustic Impact
Energy Savings
Cost Analysis
•Anticipated Payback Period:
DOAS HP
ROOFTOP HP
WATER TO WATER HP
CHILLED BEAMS
HEAT EXCHANGER
PIPING
LOOP PIPING
PUMPS
DUCTWORK
AIR VALVES
VAV BOXES
CONTROLS
TESTING AND BALANCING
HVAC COSTS:
11.17 years
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
$446,400.00
$64,000.00
$134,750.00
$267,300.00
$7,500.00
$1,909,880.00
$96,000.00
$55,200.00
$3,110,880.08
$4,563,000.00
$144,000.00
$1,441,300.00
$588,030.00
$12,828,240.08
Redesigned System Conclusions:
Presentation Material:
Building Overview
Redesign Goals
Current Mechanical System
Mechanical System Redesign
Lighting Redesign
M
M
B
T
U
•Payback period of 11.17 years
THE PENNSYLVANIA STATE UNIVERSITY
$600,000.00
Total Original Energy
$200,000.00
$0.00
APRIL 15TH 2009
$1,046,706
$1,000,000.00
$800,000.00
Total Redesign Energy
•The system redesign may not be a favorable alternative to
the original design due to significant increase in the initial cost.
AMY LEVENTRY
20,817
Original Design
$1,200,000.00
$400,000.00
•The initial cost of the redesigned system was estimated to
cost $2.5 million more.
Energy Savings
Conclusions
28,811
•This energy savings result in approximately $600,000 a
year.
Acoustic Impact
Energy Costs/year
System Redesign
•Redesign was found to be over 27% more energy efficient
than the original mechanical system design.
•Therefore the payback for the new system compared to the
original design would take slightly over four years.
Cost Analysis
Energy Comparison
$805,257
Acknowledgements:
Presentation Material:
Building Overview
Thesis Advisor
Redesign Goals
BurtHill Engineers
Current Mechanical System
Mechanical System Redesign
Lighting Redesign
Penn State
Professors
Acoustic Impact
Energy Savings
Parents
Cost Analysis
Conclusions
AMY LEVENTRY
THE PENNSYLVANIA STATE UNIVERSITY
APRIL 15TH 2009
Dr. James Freihaut
Jonathon Gridley
Tom Hovan, PE
Dustin Eplee
Matt Rooke
Kevin McCormick PE
Dr. William Bahnfleth
Dr. Moses Ling
Atty. Tim Leventry
Ruth Leventry