ENERGY EFFICIENCY/RENEWABLE ENERGY (EERE) PROJECTS IN TEXAS PUBLIC SCHOOLS

1. Jeff S. Haberl, Ph.D., P.E Zi Liu, Ph.D. Hyojin Kim Jaya Mukhopadhyay Sunglok Do Bahman Yazdani, P.E. Charles Culp, Ph.D., P.E. Juan-Carlos Baltazar, Ph.D Energy Systems Laboratory Texas A&M University ENERGY EFFICIENCY/RENEWABLE ENERGY (EERE) PROJECTS IN TEXAS PUBLIC SCHOOLS N 17thSymposium for Improving Building Conditions in Hot and Humid Climates Austin TX August 24 – 25, 2010

2. Outline Introduction Methodology Base-Case School Model Energy Efficiency Measures Results Summary

3. 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

4. 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)

5. Methodology Grouped Counties by ASHRAE 90.1-2004/2007 Climate Zones Texas Education Agency Energy Star School SECO K-12 Energy Audit Avg. Sq. ft./This Type of School Avg. Sq. ft. /Student Population Growth Rate No. of This Type of School Elementary School Avg. No. of Students/This Type of School Estimated No. of This Type of School Year This Type of School Built Middle School Four School Groups by the construction year High School Total sq. ft. for Each Base-case School in Each Climate Zone Group 1: Built Before 2000 Group 2: Built 2000 - 2007 Group 3: Built 2007-2010 Group 4: Built After 2010 Weather Zone Compliant with the corresponding ASHRAE 90.1 School Model Assumptions School Model Assumptions School Model Assumptions School Model Assumptions Assigned Weather Station ASHRAE 90.1 1989 Specifications ASHRAE 90.1 1999 Specifications ASHRAE 90.1 2004 Specifications ASHRAE 90.1 2007 Specifications EPlus Benchmark School Model Total Statewide Energy and Emissions Savings Group 1: Base-Case School Model Group 2: Base-Case School Model Group 3: Base-Case School Model Group 4: Base-Case School Model AEDG School Baseline Model Energy Savings in This County Group Simulation eGrid Survey of College Station/Bryan ISDs School Compliant with ASHRAE AEDG Savings/sq. ft. Calculation Energy Savings for Each Base-case School Individual Energy Efficiency Measures Energy and Cost Savings of each EEM Payback Calculation Cost-Effective EEM

6. 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)

7. 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)

8. 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 Average: 10% WWR

9. 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

10. 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) Classroom Gym Admin Cafe N

11. 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) Classroom Gym Admin Cafe N

12. 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) Classroom Gym Admin Cafe N

13. 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) Classroom Gym Admin Cafe N

14. Energy Efficiency Measures eQuest 3.6 Simulation Software PV-F Chart & F-Chart eQuest 3.6 Simulation Software

15. 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

16. 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

17. Results 2. Savings from Individual EEMs Higher savings for Potter County zzzzzzzzz Higher saving potential for older school groups Heating penalty for Potter County Higher savings for Potter County zzzzzzzzz z Higher saving potential for older school groups Good Saving Potential Less than 2% savings due to small DHW end-use consumption, but higher savings are expected for the K-5 to K-12 Schools. Higher savings for Potter County

18. Results 3. ASHRAE AEDG for K-12 Schools • Simulation Input

19. 20.2 % for 1999 Base Case (13.7% to 23.8% for Harris County) Results 3. ASHRAE AEDG for K-12 Schools • Simulation Results 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.

20. 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

21. 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.

22. 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).

23. ENERGY EFFICIENCY/RENEWABLE ENERGY (EERE) PROJECTS IN TEXAS PUBLIC SCHOOLS Thank You!