Developing Building Energy Use Intensity Benchmarks for Standard 100 Energy Targets

Terry Sharp, PE, CEMBuilding Technologies Research & Integration Center

Oak Ridge National Laboratory865-574-3559

sharptr@ornl.govwww.ornl.gov

Developing Building Energy Use Intensity Benchmarks for Standard 100 Energy Targets

June 27, 2010

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.

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)

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

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

Baseline Energy Use Intensities (EUIs) Developed From CBECS 2003

1 2 4 5 1-2 4-5 1 2 4 5Admin/mixed office 134 160 151 159 19 6 101 184 162 107Bank/other financial 224 241 303 264 8 -13 12 23 12 7Government office 157 196 148 164 25 11 28 31 24 17Medical Office 177 116 83 111 -35 34 13 21 15 14Other office 168 146 62 158 -13 153 13 7 11 10Laboratory 422 781 456 665 85 46 7 17 10 2Distribution 90 86 62 48 -5 -22 37 46 60 49Warehouse 42 31 31 56 -27 81 31 43 27 24Self-storage 24 18 22 24 -25 8 5 5 12 15Grocery store 531 493 548 600 -7 10 30 30 33 16Fire/police station 112 124 108 176 11 62 10 16 9 3Other public order 308 148 421 248 -52 -41 9 11 7 5Outpatient health 185 163 137 287 -12 110 17 29 18 14

ObservationsClimate Zone

CBECS Building Type

EUI (source kBtu/sqft-yr)CBECS Climate Zone Zones

Change (%)

Small observation counts

Large changes in zonal EUIs

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

Climate Zones for Benchmark Buildings

Energy Use Intensities for Benchmark Buildings by Climate Zone

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Building Type 1A 2A 2B 3A 3B 3B 3C 4A 4B 4C 5A 5B 6A 6B 7 8Medium Office 39 42 40 41 33 37 38 45 38 42 48 41 54 50 57 77

Warehouse 30 19 19 18 14 18 15 21 20 18 24 23 29 27 33 52Stand-alone Retail 62 62 60 61 44 56 50 72 61 65 81 69 93 83 104 145

Strip Mall 56 58 57 62 44 57 53 74 64 69 85 72 99 89 111 156Primary School 57 57 55 55 46 52 51 61 54 54 65 58 75 66 79 113

Secondary School 56 57 55 57 42 53 50 68 58 61 76 64 89 77 97 141Supermarket 158 167 159 170 153 158 166 184 168 180 195 179 208 197 223 266

Fast Food 535 549 538 561 496 541 524 609 566 575 657 604 713 662 765 949Restaurant 404 423 409 440 374 417 415 488 446 467 527 481 570 532 617 763

Hospital 145 147 138 142 137 135 76 148 127 139 148 130 153 137 155 185Outpatient 280 279 278 274 254 277 240 278 274 247 271 271 280 275 279 324

Motel 70 69 68 68 63 66 64 71 68 66 74 70 79 74 83 99Hotel 99 108 100 116 105 105 101 127 119 124 138 130 150 144 163 196

Mid-Rise Apartmt 39 39 38 38 31 36 33 42 37 38 47 41 54 48 59 76

DOE/NREL Benchmarks from Simulations (total site EUI in kBtu/sqft)

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?

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

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

Building Type

National Median

EUI Building Type

National Median

EUIAdministrative office 61 College/university 97Bank/other financial 87 Elementary/middle school 55Government office 77 High school 71Medical office (non-diagnostic) 52 Preschool/daycare 71Mixed-use office 71 Other classroom education 40Other office 59 Fast food 419Laboratory 266 Restaurant/cafeteria 229Distribution/shipping center 34 Other food service 125Non-refrigerated warehouse 16 Hospital/inpatient health 199Convenience store 232 Nursing home/assisted living 126Convenience store + gas 187 Dormitory/fraternity/sorority 74Grocery store/food market 193 Hotel 76Other food sales 58 Motel or inn 74Fire station/police station 98 Other lodging 71Other public order and safety 89 Vehicle dealership/showroom 82Medical office (diagnostic) 44 Retail store 47Clinic/other outpatient health 67 Other retail 82Refrigerated warehouse 103 Post office/postal center 64Religious worship 35 Repair shop 43Entertainment/culture 35 Vehicle service/repair shop 49Library 92 Vehicle storage/maintenance 21Recreation 40 Other service 90Social/meeting 41 Strip shopping mall 94Other public assembly 42 Enclosed mall 90

Mobile Home 66 Apartments in 2-4 unit buildings 76Single-family detached 44 Apartments in 5+ unit buildings 54Single-family attached 50

2005 RECS

2003 CBECS

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

Benchmark Building 1A 2A 2B 3A 3B 3B 3C 4A 4B 4C 5A 5B 6A 6B 7 8Medium Office 0.92 0.98 0.94 0.95 0.77 0.87 0.89 1.06 0.90 0.98 1.11 0.96 1.26 1.11 1.32 1.79

Warehouse 1.44 0.92 0.95 0.90 0.70 0.87 0.75 1.02 0.96 0.90 1.19 1.11 1.42 1.30 1.63 2.55Stand-alone Retail 0.90 0.90 0.87 0.89 0.64 0.80 0.71 1.04 0.88 0.94 1.17 0.99 1.35 1.20 1.50 2.10

Strip Mall 0.83 0.87 0.85 0.93 0.66 0.85 0.79 1.11 0.95 1.03 1.26 1.08 1.47 1.33 1.65 2.33Primary School 0.98 0.97 0.94 0.94 0.78 0.89 0.87 1.04 0.93 0.92 1.12 0.99 1.27 1.12 1.35 1.92

Secondary School 0.87 0.89 0.86 0.89 0.65 0.83 0.77 1.06 0.89 0.95 1.17 0.99 1.38 1.19 1.51 2.19Supermarket 0.87 0.93 0.88 0.94 0.84 0.88 0.92 1.02 0.93 1.00 1.08 0.99 1.15 1.09 1.23 1.47

Fast Food 0.91 0.93 0.91 0.95 0.84 0.92 0.89 1.03 0.96 0.97 1.11 1.02 1.21 1.12 1.30 1.61Restaurant 0.86 0.90 0.87 0.94 0.80 0.89 0.88 1.04 0.95 1.00 1.12 1.02 1.22 1.13 1.31 1.63

Hospital 1.00 1.02 0.96 0.98 0.95 0.94 0.98 1.02 0.88 0.96 1.02 0.90 1.06 0.95 1.07 1.28Outpatient health 1.03 1.02 1.02 1.00 0.93 1.02 0.88 1.02 1.00 0.91 0.99 0.99 1.03 1.01 1.02 1.19

Motel 0.95 0.95 0.93 0.95 0.83 0.91 0.86 1.01 0.94 0.93 1.07 0.99 1.17 1.07 1.24 1.51Hotel 0.81 0.89 0.82 0.95 0.86 0.87 0.92 1.05 0.98 1.02 1.14 1.07 1.23 1.18 1.34 1.61

Mid-Rise Apartment 0.95 0.95 0.93 0.94 0.77 0.89 0.80 1.04 0.92 0.94 1.16 1.02 1.34 1.19 1.46 1.87

Ratios of climate zone EUI to average of all zonal EUIs by building type (site basis)ASHRAE Climate Zone

Draft Commercial and Residential Building Energy Performance Benchmarks Based on

Integrated Development Approach (kBtu/ft2-yr)CBECSMedian

EUI 1A 2A 2B 3A 3B 3B 3C 4A 4B 4C 5A 5B 6A 6B 7 8Admin office 61 57 58 56 55 46 51 50 61 53 56 66 57 73 64 76 103Bank 87 80 83 80 79 65 73 71 87 75 79 93 81 103 92 108 147Govt office 77 71 73 70 69 57 64 63 76 66 70 82 71 91 80 95 129Medical office 52 48 50 48 47 39 44 43 52 45 48 56 48 62 55 65 88Mixed-use office 71 65 68 65 64 53 59 58 71 61 65 76 66 84 75 88 119Other office 59 55 56 55 53 44 49 48 59 51 54 64 55 70 62 74 100Warehouse 16 24 15 16 15 12 14 12 17 16 15 20 18 23 21 27 42Convenience store 232 202 214 203 218 196 203 213 235 216 231 249 230 266 252 285 341Convenience store+gas 187 163 173 164 176 158 163 172 189 174 186 201 185 215 203 230 275Grocery store 193 168 179 170 182 163 169 178 196 180 193 208 192 222 210 238 284Other food sales 58 51 54 51 55 49 51 54 59 54 58 63 58 67 64 72 86 RECS

MedianBuilding Type EUI 1A 2A 2B 3A 3B 3B 3C 4A 4B 4C 5A 5B 6A 6B 7 8Mobile home 66 63 63 61 62 51 59 53 69 61 62 77 67 89 79 96 124SF-detached 44 42 42 41 41 34 39 35 46 41 41 51 45 59 52 64 82SF-attached 50 47 48 46 47 38 44 40 52 46 47 58 51 67 59 73 93Aptmt-in 2-4 unit 76 72 72 70 71 58 67 61 79 70 71 88 77 102 90 111 142Aptmt in 5+ unit 54 51 51 50 50 41 47 43 56 49 50 62 55 72 64 78 100

Building Type

RECS Estimated Zonal Site EUIs by Building Type (kBtu/sf-yr)ASHRAE Climate Zone

CBECS Estimated Zonal Site EUIs by Building Type (kBtu/sf-yr)ASHRAE Climate Zone

Note: Results shown for 11 commercial building types due to limited space.

Zonal EUI = CBECS/RECS National Median EUI x Zonal Ratio

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