Technical Report 2
BOWIE STATE
UNIVERSITY FINE AND
PERFORMING ARTS
CENTER
Building and Plant Energy Analysis Report
Technical Report 2
Zack Lippert – Mechanical
Advisor: Steve Treado
Location: Bowie, MD
Contents
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
Executive Summary
The objective of this technical report is to perform a building HVAC load calculation and energy analysis for the Bowie State University (BSU) Fine and Performing Arts Center. Several computer programs were considered including, Trane Trace, Carrier HAP and EnergyPlus.
Ultimately Trane Trace 700 was chosen because of its accurate results, ease of accessibility and use, as well as familiarity with it from previous projects. Most of the inputs for the analysis were obtained from the building specifications and drawings, but when information was unattainable the values of typical spaces from ASHRAE standards were used.
The load calculations varied significantly from the designed documents, but the discrepancy could be due to safety factors and differences in the model. The cost analysis determined that the BSU Fine and Performing Arts building costs approximately $68,000 per year for energy. The majority of cost was from electricity and the highest electrical demand was from the lighting.
Building Overview
Bowie State University’s new Fine and Performing Arts Center is a 123,000 square foot mixed use building that contains a 400 and 200-seat theatre, a recital hall, class rooms, offices, an art gallery, a large atrium and shops for creating scenery. The north side of the building has a large expanse of glass with different colored panes spaced in a pattern to look like sheet music.
The numerous acoustical considerations have made this a wonderful building to enjoy musical and theatrical performances.
There are 3 MAUs with enthalpy wheels that provide ventilation air to the 16 AHUs, which provide conditioned air to the building through VAV systems. There is two 1,712 MBH gas-fired boilers and there is one 305 ton air cooled chiller on site.
Room Categories
The BSU Fine and Performing Arts building is a multiuse building and therefore has several different types of spaces in it. Each of these spaces has to be modeled differently because they have different requirements and internal loads. All of the rooms have been categorized into the labels in Table 1.
Break Room
Dock
Lecture Hall
Stage/Studio
Class Room
Storage
Room Categories
Computer Lab
Equipment Room
Lobby
Gallery
Office
Theatre
Table 1: Room Categories
Corridor
Laundry Room
Rest Room
Wood/Metal Shop
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
System Design Load Estimation
In order to estimate the heating and cooling loads for the Fine and Performing Arts building Trane Trace 700 was used. The program used numerous inputs to calculate the heating and cooling loads for an entire year in order to determine the peaks for both. Each room was modeled and assigned a template for Internal Loads, Airflow, Thermostat, Construction and
Room. Examples of each of these templates can be found in Appendix A.
Model Inputs
There were numerous inputs for the model. For the Internal Loads templates the density for each room was found by using the furniture plans. It was assumed that at full capacity each desk and work station was occupied. The heat gain from lighting loads were found from the electrical drawings when available and Table 9.6.1 of ASHRAE 90.1-2007 was used when the heat gain for a room was not provided. Miscellaneous loads were calculated from the architectural drawings and from Trace recommendations for certain spaces.
The Airflow template used ASHRAE Standard 62.1-2007 for the ventilation rates for each space type. The infiltration type was set to Neutral, Tight Construction, which allows for
0.3 air changes per hour. The thermostat settings were set to match the building operating settings. The Construction template values were found in the structural drawing and the building specifications. Since the building has dozens of ceiling heights between eight and twelve and half feet high, an average value of ten feet was used for the majority spaces.
However, in certain areas that had much higher ceilings (such as the main theatre) exact values were entered. All of the schedules were set to 100% available in order to determine the absolute peak loads for heating and cooling.
The weather information for the analysis uses ASHRAE Climate Data from Baltimore,
Maryland which is only thirty miles away from Bowie, which is why it was selected. Table 2 shows the design temperatures used.
Summer
Winter
Design Outside Air Temperatures
Dry Bulb
91°F
13°F
Table 2: Design OA Temperatures
Wet Bulb
77 °F
N/A
Load Calculation Results and Comparison
The results from the load calculations compared to the actual designed values are provided in Table 3. The peak heating and cooling loads from the Trace calculations are both much less than the equipment in the building is sized for. This could be due to several reasons.
The Trace model only calculated the load that the AHUs were handling, but the boilers and
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
chillers must also provide conditioned water for domestic services since there is a kitchen, bathrooms and showers. Also, the Trace model did not consider the MAUs and preheat coils.
Another reason that the actual designed equipment is larger than the calculated loads is because it most likely has a safety factor built in to make sure that it can always meet the design conditions.
The supply air for the model is slightly higher than the designed supply air. The Trace model has the AHUs that condition the main theatre supplying much more air to the space than what is designed. One reason for this is that the Trace model is supplying air to all four stories of the main theatre, but in reality only the first two stories are occupied. That could explain the discrepancy between the model and the designed supply air.
The Trace model calculated the ventilation air to be a bit less than the actual design as well. This could be due to the designers modeling certain spaces in a different way or simply by adding in a large safety factor, since several of the rooms could have noxious fumes present.
BSU Trace Model
BSU Designed
Peak Heating
(MBH)
749.3
3424
Peak Cooling
(tons)
211.3
304.9
Supply Air
(cfm)
95,012
81,635
Table 3: Load Calculation Results vs. Actual Design Conditions
Ventilation Air
(cfm)
23,777
42,635
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
System Energy Consumption and Operating Costs
Trace was once again used to calculate the energy consumption of the HVAC system.
The AHUs were modeled as variable volume reheat with 30% minimum flow. All of the air is preconditioned by an enthalpy wheel before reaching the AHUs; therefore a total-energy wheel has been added to each AHU. A schematic of the typical AHU layout is in Appendix B. The chiller was modeled as a 305 ton air cooled chiller with a 10.7 EER rating. Two boilers were also added.
They are both 1712 MBH gas fired water boilers with an efficiency of 81.5 percent. The schedule that the equipment was set to for the energy analysis is shown in table 4.
Start Time
Midnight
6 a.m.
8 a.m.
Noon
1 p.m.
5 p.m.
6 p.m.
End Time
6 a.m.
8 a.m.
Noon
1 p.m.
5 p.m.
6 p.m.
Midnight
Table 4: Weekday Schedule
Percentage
0
50
100
30
100
50
0
The results of the energy analysis are in charts 1 and 2. Chart 1 shows that natural gas consumption peaks in the winter and drops to zero in the summer. This is because only the boiler uses natural gas and the building does not need heated in the summer. Also, the electric consumption peaks in the summer and decreases in the winter but only by about half. The chiller has an electric condenser which consumes most of the energy for space cooling, which is why the electric consumption peaks in the hottest months. Unlike the gas however, it doesn’t drop to zero when it’s not cooling because there are still lighting and receptacles loads. Chart 2 shows how the total energy consumed in the year is distributed. Lighting is the largest, which seems reasonable considering the large amount of lights required for the several performing arts spaces.
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
Chart 1: Monthly Energy Consumption
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
Percent of Total Building Energy
10,4%
28,4%
38,0%
Primary Heating
Primary Cooling
Pumps
Lighting
Recptacles
17,9%
5,4%
Chart 2: Building Energy Consumption
Energy Cost
The rates that were used for the cost estimate were obtained from Baltimore Gas and
Electric (BGE). The rates were used to determine the monthly energy cost for both gas and electric. Chart 3 shows the total monthly energy cost broken up into electric and gas. The electric clearly dominates the total monthly costs.
Natural Gas
Electricity
Rate
$0.20/therm
$0.0927/kWh
Table 5: Energy Rates
Demand
N/A
$3.95/kW
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
Chart 3: Monthly Utility Costs
Environmental Impact
An environmental impact analysis was performed as well. Table 6 has the result, showing the total value for the entire year. It considers three greenhouse gases; CO
2
, SO
2
and
NOX.
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
CO
2
Environmental Impact
1,035,798 lbm/year
SO
2
8,840 gm/year
NOX 1,872 gm/year
Table 6: Environmental Impact Analysis
Energy Analysis Conclusion
The total amount of energy that the BSU Fine and Performing Arts building uses is 2.73 million kBTU/year. The natural gas is mainly used for the boiler which provides hot water to the heating coils. Therefore the natural gas consumption peaks in the winter when heating is needed.
Likewise, the electricity consumption peaked in the summer when the chiller was working the hardest. The cost analysis showed that the yearly cost for energy in the building is just under
$68,000. The vast majority of the cost comes from electricity which accounts for not only cooling, but also the lights, receptacles and equipment.
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
References
ASHRAE.2007, ANSI/ASHRAE, Standard 62.1-2007, Ventilation for Acceptable
Indoor Air Quality. American Society of Heating Refrigeration and Air-
Conditioning Engineer, Inc. Atlanta, GA.
ASHRAE.2007, ANSI/ASHRAE, Standard 90.1-2007, Energy Standard for
Building Except Low-Rise Residential Buildings. American Society of Heating
Refrigeration and Air-Conditioning Engineers, Inc. Atlanta, GA.
Baltimore Gas and Electric. <www.bge.com>
EYP Architecture & Engineering, P.C. Architectural Construction Documents.
EYP Architecture & Engineering, Washington D.C.
EYP Architecture & Engineering, P.C. Electrical Construction Documents. EYP
Architecture & Engineering, Washington D.C.
EYP Architecture & Engineering, P.C. Mechanical Construction Documents.
EYP Architecture & Engineering, Washington D.C.
"Natural Gas Prices - Energy Explained, Your Guide To Understanding
Energy." U.S. Energy Information Administration (EIA). U.S. Department of
Energy, 17 Dec. 2010. Web. 22 Oct. 2011.
<http://www.eia.gov/energyexplained/index.cfm?page=natural_gas_prices>.
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
Appendix A: Sample Templates
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
Appendix B: AHU System Schematic
BSU Fine and Performing Arts Center 10/22/2011 Zack Lippert
