Developing Building Energy Use Intensity Benchmarks for Standard 100 Energy Targets

1. Developing Building Energy Use Intensity Benchmarks for Standard 100 Energy Targets Terry Sharp, PE, CEM Building Technologies Research & Integration Center Oak Ridge National Laboratory 865-574-3559 sharptr@ornl.gov www.ornl.gov June 27, 2010

2. Presentation Topics Current needs for existing buildings energy performance benchmarks and targets Strengths and weaknesses of two development approaches An integrated synergistic approach Benchmark results NOTE: All results shown in this presentation are preliminary.

3. Existing Buildings Energy Performance Baselines and Targets Are Needed For: • ASHRAE Energy Performance Standard • ANSI/ASHRAE/IESNA Standard 100-2006 Revision, Energy Efficiency in Existing Buildings • Need: Benchmark and Targets • Energy Use Reductions in Federal Buildings • Energy Independence & Security Act (EISA 2007) • Need: Benchmark (based on CBECS 2003) • Targets Established (percent below benchmark)

4. Option 1: Benchmark Via Commercial Buildings Energy Consumption Survey (CBECS 2003) • Strengths: • National survey of U.S. buildings • 5215 observations • 51 building types • 6 Office 5 Education • 5 Services 5 Assembly • 4 Food sales 4 Lodging • 3 Restaurant 3 Retail • Balance: health care, public order, malls, warehouse, etc. • 5 climate zones • Real buildings, real energy use data

5. Option 1: Benchmark Via Commercial Buildings Energy Consumption Survey (CBECS 2003) • Weaknesses: • Need to split observations for 51 building types across 5 climate zones • Statistical stability decreases proportional to splits • Low observation counts occur for many building types in many climate zones -- decreased reliability • CBECS sampling weights amplify instabilities

6. Baseline Energy Use Intensities (EUIs) Developed From CBECS 2003 Large changes in zonal EUIs Small observation counts

7. Option 2: Benchmark Via Simulation Results From Dept. of Energy Benchmark Buildings • Strengths: • Results readily available • Proto-typical buildings of different types • Modeling performed across ASHRAE’s 15 U.S. climate zones (ASHRAE Standard 90.1-2007) • Building models well accepted for R&D purposes • Stable predictions

8. Climate Zones for Benchmark Buildings

9. Energy Use Intensities for Benchmark Buildings by Climate Zone

10. Option 2: Benchmark Via Simulation Results From Dept. of Energy Benchmark Buildings • Weaknesses: • One building represents population • One city represents a climate zone • Limited building types • Simulated values = real building values?

11. Option 3: The Integrated Approach • Derive CBECS national median EUIs • Provides real building basis • Retains large sample sizes • Derive ratios of zonal to national average EUIs from building simulations (Department of Energy benchmark buildings) • Use ratios to proportion the CBECS national medians to the 15 ASHRAE climate zones

12. CBECS – National Median Energy Use Intensities by Building Type (kBtu/sqft-yr)

13. Benchmark Buildings: Ratios of Zonal to Average EUIs by Building Type

14. Draft Commercial and Residential Building Energy Performance Benchmarks Based on Integrated Development Approach (kBtu/ft2-yr) Note: Results shown for 11 commercial building types due to limited space. Zonal EUI = CBECS/RECS National Median EUI x Zonal Ratio

15. Summary • Integrated approach combines strengths of different options • Approach produces regional benchmarks (leading to energy targets) • Provides results for both commercial and residential buildings • Process is straight-forward