ENERGY EFFICIENCY/RENEWABLE ENERGY (EERE) PROJECTS IN TEXAS PUBLIC SCHOOLS
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Transcript of ENERGY EFFICIENCY/RENEWABLE ENERGY (EERE) PROJECTS IN TEXAS PUBLIC SCHOOLS
ENERGY EFFICIENCY/RENEWABLE ENERGY (EERE) PROJECTS IN TEXAS PUBLIC SCHOOLS
17th Symposium for Improving Building Conditions in Hot and Humid ClimatesAustin TX August 24 – 25, 2010
Jeff S. Haberl, Ph.D., P.EZi Liu, Ph.D.
Hyojin KimJaya Mukhopadhyay
Sunglok DoBahman Yazdani, P.E.
Charles Culp, Ph.D., P.E.Juan-Carlos Baltazar, Ph.D
Energy Systems LaboratoryTexas A&M University
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Energy Efficiency/Renewable Energy (EERE) Projects in Texas Public Schools17th Symposium for Improving Building Conditions in Hot and Humid Climates
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Outline
Introduction
Methodology
Base-Case School Model
Energy Efficiency Measures
Results
Summary
Energy Efficiency/Renewable Energy (EERE) Projects in Texas Public Schools17th Symposium for Improving Building Conditions in Hot and Humid Climates
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Introduction
Energy Saving Potential in High Performance Schools Energy use of the most efficient schools = 1/3 energy of the least efficient
schools (EPA 2010) 20% to 40% energy savings in high performance schools (Im and Haberl
2006)
Energy Saving Potential in Texas Public Schools Average age of Texas public schools (2006 survey of Texas Comptroller of Public Accounts)
- Elementary schools: 35.2 years old- Middle schools: 32.2 years old- High schools: 32.7 years old
Average enrollment growth rate of Texas public schools (TEA 2009)- 20.1% over the past 10-year period
Huge energy saving potential in both existing and new schools in Texas from the application of high performance strategies
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Introduction
Energy Efficiency/Renewable Energy (EERE) Projects in Texas Public Schools
Goal- To produce an analysis of the potential energy savings, and resultant air pollution
reductions associated with the energy savings from the application of cost-effective energy efficiency and renewable energy projects applied to new and existing Texas Independent School Districts (ISDs)
Process- Preliminary results from an analysis of the energy saving potential in new and
existing Texas Independent School Districts (ISDs)
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Methodology
Grouped Counties by ASHRAE 90.1-
2004/2007 Climate Zones
Grouped Counties by ASHRAE 90.1-
2004/2007 Climate Zones
Elementary SchoolElementary School
Middle SchoolMiddle School
High SchoolHigh School
Avg. No. of Students/This Type of School
Avg. No. of Students/This Type of School
Energy Star School
Energy Star School
Texas Education
Agency
Texas Education
Agency
Group 1: Built Before
2000
Group 1: Built Before
2000
SECO K-12 Energy Audit
SECO K-12 Energy Audit
No. of This Type of School
No. of This Type of School
Avg. Sq. ft. /Student
Avg. Sq. ft. /Student
Avg. Sq. ft./This Type of SchoolAvg. Sq. ft./This Type of School
Year This Type of School Built
Year This Type of School Built
Group 2: Built 2000 -
2007
Group 2: Built 2000 -
2007
Group 3: Built 2007-
2010
Group 3: Built 2007-
2010
Total sq. ft. for Each Base-case School in Each Climate Zone
Estimated No. of This Type of
School
Estimated No. of This Type of
School
Population Growth RatePopulation
Growth Rate
Group 4: Built After
2010
Group 4: Built After
2010
School Model AssumptionsSchool Model Assumptions
Group 1: Base-Case School Model
ASHRAE 90.1 1989 Specifications
ASHRAE 90.1 1989 Specifications
ASHRAE 90.1 1999 Specifications
ASHRAE 90.1 1999 Specifications
ASHRAE 90.1 2004 Specifications
ASHRAE 90.1 2004 Specifications
School Model AssumptionsSchool Model Assumptions
School Model AssumptionsSchool Model Assumptions
Group 2: Base-Case School Model
Group 3: Base-Case School Model
ASHRAE 90.1 2007 Specifications
ASHRAE 90.1 2007 Specifications
School Model AssumptionsSchool Model Assumptions
Group 4: Base-Case School Model
Weather ZoneWeather Zone
Assigned Weather Station
Assigned Weather Station
EPlus Benchmark School Model
EPlus Benchmark School Model
Survey of College Station/Bryan ISDsSurvey of College
Station/Bryan ISDs
AEDG School Baseline Model
AEDG School Baseline Model
School Compliant with ASHRAE AEDGSchool Compliant
with ASHRAE AEDG
Individual Energy Efficiency Measures
Individual Energy Efficiency Measures
SimulationSavings/sq. ft.
Energy and Cost Savings of each
EEM
Payback Calculation Cost-Effective EEMCost-Effective EEM
Energy Savings for Each Base-case School
Energy Savings for Each Base-case School
Energy Savings in This County Group
Energy Savings in This County Group
Total Statewide Energy and Emissions SavingsTotal Statewide Energy and Emissions Savings
Calculation
eGrid
Four School Groups by the construction year
Compliant with the corresponding ASHRAE 90.1
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Methodology
Simplified Approach Grouped counties by ASHRAE 90.1-
2004/2007 Climate Zones
Representative County for Each Climate Zone
- Harris County for Climate Zone 2- Dallas County for Climate Zone 3- Potter County for Climate Zone 4
Harris(Houston TMY 2)
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Methodology
Development of Base-Case Model (1/2)Sources
- ASHRAE Standard 90.1-1989, 1999, 2004, and 2007- U.S. EPA Energy Star labeled schools in Texas (2010)- Texas Education Agency K-12 schools database (2010)- EnergyPlus Benchmark school models (2010)- NREL’s technical support document of the Advanced Energy Design Guide
(AEDG) for K-12 schools (2007)
Floor area- U.S. EPA Energy Star labeled schools in Texas (2010)- Texas Education Agency K-12 schools database (2010)
Texas Education Agency (TEA) Energy StarEstimated Avg.
sq.ft./schoolNo. of Schools
No. of Student
Avg. No. of Student/school
No. of Schools
No. of Student
Total Floor Area (sq.ft.)
Avg. sq.ft. per student
Elementary 3,919 2,169,097 553 105 59,969 8,578,253 143 79,173
Middle 1,613 1,002,912 622 31 24,105 4,473,684 186 115,395
High 1,226 1,214,495 991 15 24,708 4,711,418 191 188,894
Total 8,276 4,710,935 160 110,202 19,059,308
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Methodology
Development of Base-Case Model (2/2)Window-to-wall (WWR) ratio
- Field survey of elementary schools in Bryan/College Station school district
Schedules (occupancy/lighting/equipment/DHW/heating & cooling set-points) and HVAC/DHW system type
- EnergyPlus Benchmark primary school model (2010)- NREL’s technical support document (2007) of the AEDG for K-12
Building envelope construction and HVAC/DHW system efficiency and control- ASHRAE Standard 90.1-1989, 1999, 2004, and 2007
-
Bryan College Station
School 1 School 2 School 3 School 4 School 5 School 6
Year Built 2009 1999 1990 1996 1999 2007
Total Window Area (sq.ft.) 2,352 1,453 2,594 2,929 3,443 2,065
Total Wall Area (sq.ft.) 17,942 19,724 22,541 22,403 30,979 32,517
WWR (%) 13.1% 7.4% 11.5% 13.1% 11.1% 6.4%
Average: 10% WWR
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Methodology
Development of Energy Efficiency Measures Sources
- ASHRAE’s AEDG for K-12 Schools (2008)- Collaborative for High Performance Schools (CHPS) Best Practices Manual
(2006)- U.S. EPA Energy Star Building Upgrade Manual (2008)
Interview with a Maintenance Manager of College Station school district
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Base-Case School Model (1/4)
Building Envelope Common characteristics
- 1 story, 79,430 ft2 - 10% WWR- Steel framed with 4” studs at 16” o.c.- Concrete slab-on-grade floor- Flat built-up roofing
Climate-specific characteristics according to the corresponding requirements of the ASHRAE 90.1-1989, 1999, 2004, and 2007
- ASHRAE 90.1-1999 Wall R-value: R-13 Roof R-value: R-15 c.i. Glazing U-value: 1.22 Btu/hr ºF ft2 (CZ 2&3) 0.57 Btu/hr ºF ft2 (CZ 4) Glazing SHGC: 0.25 SHGC (CZ 2) 0.39 SHGC (CZ 3&4)
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Classroom
Admin
Cafe
Gym
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Base-Case School Model (2/4)
Space Conditions Common characteristics
- Heating: 70 ºF (60.8 ºF setback)- Cooling: 77 ºF (87.8 ºF setup)- EPD: 1.06 W/ft2
Code-specific characteristics- LPD: 1.57 W/ft2 (1989) 1.50 W/ft2 (1999) 1.20 W/ft2 (2004 & 2007)
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Classroom
Admin
Cafe
Gym
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Base-Case School Model (3/4)
HVAC System Characteristics Common characteristics
- 30 ton PVAVS for Classrooms- 10 ton PSZ for Admin/Café/Gym- 80% eff. gas boilers and furnaces- Supply air flow Classroom: 1.00 cfm/ft2
Admin: 1.03 cfm/ft2
Café: 1.69 cfm/ft2
Gym: 1.72 cfm/ft2
- Ventilation: 15% of design flow
Code-specific characteristics- PVAVS: 8.5 EER & 1.7 hp/1,000 cfm (1989) 9.5 EER & 1.7 hp/1,000 cfm (1999) 9.3 EER & 1.7 hp/1,000 cfm (2004) 9.8 EER & 1.5 hp/1,000 cfm (2007) - PSZ: 8.9 EER & 1.2 hp/1,000 cfm (1989) 10.3 EER & 1.2 hp/1,000 cfm (1999) 10.1 EER & 1.2 hp/1,000 cfm (2004) 11.0 EER & 1.1 hp/1,000 cfm (2007)
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Classroom
Admin
Cafe
Gym
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Base-Case School Model (4/4)
DHW System Characteristics Common characteristics
- Two 125 gallon & 199,000 Btu/hr gas storage water heaters
- DHW daily consumption: 0.8 gal/student/day
Code-specific characteristics- DHW heater eff.: 77% (1989) 80% (1999, 2004, and 2007)
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Classroom
Admin
Cafe
Gym
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Energy Efficiency MeasuresEEM
#Individual EEM
Base Case Input
EEM InputCZ 2 (Harris County) CZ 3 (Dallas County) CZ 4 (Potter County)
1989 1999 2004 2007 1989 1999 2004 2007 1989 1999 2004 2007
Envelope Measures
1 Increased Roof Insulation R-14 R-15 R-20 R-16 R-15 R-20 R-16 R-15 R-20 R-25
2 Decreased Glazing U-Value U-1.15 U-1.22 U-0.75 U-1.15 U-1.22 U-0.57 U-0.65 U-0.81 U-0.57 U-0.57 U-0.40 U-0.45
3 Decreased Infiltration Classroom: 0.085 cfm/ft2; Admin 0.083 cfm/ft2; Café: 0.087 cfm/ft2; Gym: 0.07 cfm/ft2 40% Reduction
Lighting Measures
4 Decreased LPD (W/ft2) 1.57 1.5 1.2 1.57 1.5 1.2 1.57 1.5 1.2 1.1 W/ft2
5 Occupancy Sensor No Occupancy Sensor Occupancy Sensor
6 Daylight Dimming Controls No Daylight Dimming Controls Continuous Dimming Controls
7 Skylights 0% SRR 4% SRR for Gym and Café
HVAC System Measures
8 OA Demand Control 15% of design flowClass/Admin: 15 cfm/person
Café/Gym: 20 cfm/person
9 Improved AC Efficiency (PVAVS and PSZ EER)
8.58.9
9.510.3
9.310.1
9.811.0
8.58.9
9.510.3
9.310.1
9.811.0
8.58.9
9.510.3
9.310.1
9.811.0
PVAVS:10.6 EERPSZ:12.2 EER
10 Improved Heating System Efficiency
80% 90%
11 Decreased Supply Fan Power Consumption
PVAVS:1.7 hp/1000 cfmPSZ 1.2 hp/1000 cfm
1.51.1
PVAVS:1.7 hp/1000 cfmPSZ 1.2 hp/1000 cfm
1.51.1
PVAVS:1.7 hp/1000 cfmPSZ 1.2 hp/1000 cfm
1.51.1
PVAVS:1.3 hp/1000 cfmPSZ 1.0 hp/1000 cfm
12 PVAVS with VFD for Fan Control
Inlet Vanes VFD
13 PVAVS with Variable Speed for HW Pump
Constant Variable
DHW Measures
14 Improved DHW Heater Efficiency
77% 80% 77% 80% 77% 80% 95%
15 Tankless Water Heater DHW SL: 2% & DHW pump electric power: 0.00381 W/BtuhDHW SL: 0.3%
Pump elec. power: 0 W/Btuh
Renewable Measures
16 Solar PV No PV 200 kW PV (20% of Roof Area)
17 Solar DHW No SDHWTwo SDHW
(One unit: 128 sq.ft., 120 gal )
18 Ground Source Heat Pump No GSHPVertical GSHP
(120 Boreholes, 240 depth)
eQuest 3.6 Simulation Software
eQuest 3.6 Simulation Software
PV-F Chart & F-Chart
Energy Efficiency/Renewable Energy (EERE) Projects in Texas Public Schools17th Symposium for Improving Building Conditions in Hot and Humid Climates
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Results
1. Base-Case Energy Use for Different School Groups in Each Climate Zone
2. Savings from Individual EEMs
3. ASHRAE AEDG for K-12 Schools
Energy Efficiency/Renewable Energy (EERE) Projects in Texas Public Schools17th Symposium for Improving Building Conditions in Hot and Humid Climates
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Results
1. Base-Case Energy Use for Different School Groups in Each Climate Zone
High lighting & equipment energy consumption for all counties
High heating consumption for Potter County
Energy Efficiency/Renewable Energy (EERE) Projects in Texas Public Schools17th Symposium for Improving Building Conditions in Hot and Humid Climates
2. Savings from Individual EEMs
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ResultsEEM #
Individual EEM
Annual Total Savings Above Base Case (%)
Harris County (Climate Zone 2) Dallas County (Climate Zone 3) Potter County (Climate Zone 4)
1989 1999 2004 2007 1989 1999 2004 2007 1989 1999 2004 2007
Envelope Measures
1 Increased Roof Insulation 0.5% 0.9% 1.0% 0.4% 1.0% 1.2% 1.4% 0.6% 2.4% 2.8% 2.8% 1.2%
2 Decreased Glazing U-Value 1.4% 2.4% 2.9% 0.9% 2.2% 2.5% 0.5% 1.0% 3.3% 1.2% 1.2% -
3 Decreased Infiltration 1.6% 1.8% 2.1% 2.0% 2.3% 2.4% 2.7% 2.8% 5.6% 5.8% 6.1% 6.4%
Lighting Measures
4 Decreased LPD 7.1% 5.4% 1.3% 1.3% 6.1% 5.0% 1.3% 1.2% 2.3% 1.4% 0.3% 0.3%
5 Occupancy Sensor for Lighting Control 1.7% 1.5% 1.1% 1.1% 1.4% 1.3% 1.1% 1.0% 0.6% 0.4% 0.2% 0.2%
6 Daylight Dimming Controls 9.6% 6.6% 4.9% 5.0% 11.2% 6.0% 3.9% 3.5% 3.5% 2.5% 1.4% 1.6%
7 Skylights 1.9% 1.9% 1.4% 1.6% 1.6% 1.1% 0.8% 0.9% -0.8% -0.9% -1.3% -1.2%
HVAC System Measures
8 OA Demand Control 4.5% 4.6% 5.1% 4.8% 4.7% 4.4% 4.7% 4.7% 8.5% 9.2% 9.9% 9.6%
9 Improved AC Efficiency 6.8% 3.0% 3.6% 3.2% 6.0% 2.6% 3.2% 2.7% 3.5% 1.4% 1.6% 1.5%
10 Improved Heating System Efficiency 0.8% 1.0% 1.3% 1.1% 1.1% 1.3% 1.4% 1.5% 2.4% 2.9% 3.3% 3.1%
11 Decreased Supply Fan Power Consumption 3.5% 3.6% 3.7% 1.9% 3.5% 3.6% 3.8% 1.9% 3.3% 3.3% 3.4% 1.8%
12 PVAVS with VFD for Fan Control 5.6% 5.6% 5.8% 5.3% 5.4% 5.5% 5.8% 5.2% 4.5% 4.3% 4.3% 3.9%
13 PVAVS with Variable Speed for HW Pump 2.4% 2.4% 2.6% 2.5% 2.1% 2.2% 2.3% 2.3% 2.8% 2.7% 2.8% 2.9%
DHW Measures
14 Improved DHW Heater Efficiency 0.7% 0.6% 0.6% 0.6% 0.7% 0.6% 0.6% 0.6% 0.7% 0.5% 0.5% 0.6%
15 Tankless Water Heater 1.1% 1.1% 1.1% 1.2% 1.1% 1.1% 1.2% 1.2% 1.0% 1.0% 1.0% 1.0%
Renewable Measures
16 Solar PV 17.9% 18.8% 19.5% 20.4% 20.1% 21.0% 22.3% 22.8% 20.1% 20.0% 20.1% 21.3%
17 Solar DHW 2.4% 2.4% 2.5% 2.6% 2.7% 2.7% 2.8% 2.9% 2.7% 2.6% 2.6% 2.7%
18 Ground Source Heat Pump 6.4% 7.6% 11.2% 10.0% 10.5% 11.2% 12.6% 14.2% 21.0% 24.2% 28.3% 26.9%
Combinations
1 AEDG 23.8% 20.2% 17.4% 13.7% 25.0% 21.5% 16.7% 14.9% 23.9% 24.6% 23.9% 19.4%
2 ASHRAE 90.1 2007 11.9% 7.6% 4.2% - 11.7% 7.5% 2.0% - 5.8% 6.3% 5.6% -
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Higher savingsfor Potter County
Heating penaltyfor Potter County
Higher saving potential for older school groups
Higher savings for Potter County
Higher saving potential for older school groups
Higher savingsfor Potter County
Less than 2% savings due to small DHW end-use consumption, buthigher savings are expected for
the K-5 to K-12 Schools.
Good Saving Potential
Energy Efficiency/Renewable Energy (EERE) Projects in Texas Public Schools17th Symposium for Improving Building Conditions in Hot and Humid Climates
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Results
3. ASHRAE AEDG for K-12 Schools Simulation Input
EEM #
Individual EEMAEDG
Climate Zone 2 Climate Zone 3 Climate Zone 4
1 Increased Roof Insulation R-25
2 Decreased Glazing U-Value U-0.45 U-0.42
4 Decreased Lighting Power Density 1.1 W/ft2 0.9 W/ft2
5 Occupancy Sensor for Lighting Control Occupancy Sensor
6 Daylight Dimming Controls Daylight Dimming Controls
8 OA Demand Control Classroom/Admin: 15 cfm/person; Café/Gym: 20 cfm/person
9 Improved AC Efficiency PVAVS: 10.6 EER; PSZ 11.3 EER
10 Improved Heating System Efficiency 80% 85% 85%
11 Decreased Supply Fan Power Consumption PVAVS:1.3 hp/1000 cfm; PSZ 1.0 hp/1000 cfm
14 Improved DHW Heater Efficiency 90%
- Exterior Wall Insulation Not Required R-3.8 c.i. R-7.5 c.i.
- Window Shading 0.5 projection factor (2.5 ft) for East, West, and South
- High Albedo Roof 0.3 0.3 0.7
- Glazing SEER 0.25 0.25 0.40
Energy Efficiency/Renewable Energy (EERE) Projects in Texas Public Schools17th Symposium for Improving Building Conditions in Hot and Humid Climates
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Results
3. ASHRAE AEDG for K-12 Schools Simulation Results
20.2 % for 1999 Base Case (13.7% to 23.8% for Harris County)
21.5% for 1999 Base Case (14.9% to 25.0% for Dallas County)
24.6% for 1999 Base Case (19.4% to 24.6% for Potter County)
AEDG could be improved with renewable energy options.
Energy Efficiency/Renewable Energy (EERE) Projects in Texas Public Schools17th Symposium for Improving Building Conditions in Hot and Humid Climates
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Summary (1/2)
Energy Efficiency/Renewable Energy (EERE) Projects in Texas Public Schools
Preliminary results from an analysis of the energy saving potential in new and existing Texas ISDs
K-12 simulation model based on the DOE-2.1e program that uses ASHRAE Standard 90.1 code-compliant, 79,430 sq.ft., school buildings for three climate zones in Texas
Four base cases (ASHRAE Standard 90.1-1989, 1999, 2004, and 2007) for each climate zone
Eighteen energy efficient measures
Energy Efficiency/Renewable Energy (EERE) Projects in Texas Public Schools17th Symposium for Improving Building Conditions in Hot and Humid Climates
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Summary (2/2)
Best Individual EEMs Renewable energy options (Solar PV and GSHP): Largest savings Lighting measures (daylight dimming controls and decreased lighting
power density): High savings except Potter County due to the increased heating penalty
OA demand control and PVAVS with VFD: Good potential Improved AC efficiency and decreased fan power consumption: high
savings for older school groups (1989 base case)
ASHRAE AEDG 20.2% to 24.6% of a combined savings above 1999 base case (schools
that built between 2000 and 2007) AEDG could be improved with renewable energy options.
Energy Efficiency/Renewable Energy (EERE) Projects in Texas Public Schools17th Symposium for Improving Building Conditions in Hot and Humid Climates
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Future Work & Acknowledgement
Future Work Estimation of the total state-wide energy and emissions (NOx, SO2, and
CO2) savings potential Cost and payback analysis
Acknowledgement Funding for this study was provided by the U.S. EPA through the
Laboratory’s Center for Excellence on Displaced Emission Reduction (CEDER) and by the Texas State Legislature through the Texas Emissions Reduction Program (TERP).
ENERGY EFFICIENCY/RENEWABLE ENERGY (EERE) PROJECTS IN TEXAS PUBLIC SCHOOLS
Thank You!