approaches for benchmarking energy performance
DESCRIPTION
Approaches for Benchmarking Energy Performance. by Terry Sharp ASHRAE Winter Meeting - 2002. http://www.energystar.gov/ http://eber.ed.ornl.gov/benchmark/. Benchmarking Approaches. Averages Medians Simple Ranking Normalized Ranking. 25. Median =72 (50%). 20. Average =90 (62%). 15. - PowerPoint PPT PresentationTRANSCRIPT
1
Approaches for Benchmarking Energy Performance
by Terry Sharp
ASHRAE Winter Meeting - 2002
http://www.energystar.gov/http://eber.ed.ornl.gov/benchmark/
2
Benchmarking Approaches
Averages Medians Simple Ranking Normalized Ranking
3
Distributions of Building Energy Use Intensities (EUIs) Are Skewed
0
5
10
15
20
25
20 40 60 80 100 120 160 200
Energy Use Intensity Bin (kBtu/sqft-yr)
Sam
ple
Per
cen
t
Average =90 (62%)
Median =72 (50%)
4
EUIs: Averages Versus Medians
69 69 71
5464
0
20
40
60
80
Location in Distribution
(%)
Median EUI 50 50 50 50 50
Average EUI 69 69 71 54 64
Educ. OfficeLodgeHealth Food
5
Distributions of Building Energy Use Intensities (EUIs) Are Skewed
0
5
10
15
20
25
20 40 60 80 100 120 160 200
Energy Use Intensity Bin (kBtu/sqft-yr)
Sam
ple
Per
cen
t
Average =90 (62%)
Median =72 (50%)
6
A Cumulative Distribution of Building EUIs Can Be Used to Rank
0
20
40
60
80
100
20 40 60 80 100 120 160 200
Energy Use Intensity Bin (kBtu/sqft-yr)
Cu
mu
lati
ve P
erce
nt
7
A Cumulative Distribution Can Serve as a Rating Tool
Electric Use
(kWh)
Other Fuel Use (MMBtu)
860000 2840
Floor Area
(sq-ft)EUI
(kBtu/sf)
103000 114
Rating:
259Sample
size:
51
0
20
40
60
80
100
0 50 100 150 200Energy Use Intensity (kBtu/sf-yr)
Rating
X-- MacAuthur High
Beeks Elem -----XX-- Boone
8
Building Operational Characteristics Impact Energy Use Intensity
1
10
100
1000
10000
0.1 1.0 10.0
Worker Density (number/1000 sqft)
EU
I (k
Btu
/sq
ft-y
r)
9
Drivers of Energy Use
Floor Area
Operating Hours
HDD/ CDD
Occupancy (workers, students,
beds)
Office H M L MSchools H M M HHospitals H NA L HRestaurants M M L HLaboratories H NA L NA
10
A Cumulative Distribution Can Serve as a Rating Tool
Electric Use
(kWh)
Other Fuel Use (MMBtu)
860000 2840
Floor Area
(sq-ft)EUI
(kBtu/sf)
103000 114
Rating:
259Sample
size:
51
0
20
40
60
80
100
0 50 100 150 200Energy Use Intensity (kBtu/sf-yr)
Rating
11
Site and Source Energy Use Conversions
Site basis: 1 kWh = 3.412 Btu
Source basis: 1 kWh = 3.412 x 3.02 = 10.3 Btu
12
For Comparisons, Understanding Site and Source Energy Is Critical
0
40
80
Energy Use Intensity (kBtu/sf-yr)
Rating
Building Type Site Source Site SourceAll Elect (n=310 & 65) 57 173 37 110
Part Elect (n=1065 & 661) 80 175 69 117Difference 40% 1% 89% 6%
Office EUI K-12 School EUI
All electric --
-- Part electric
13
Summary
Beware averages Simple ranking by EUI is a good
approximation for comparisons Ranking where important secondary
drivers are accounted for is best Limited and simple data needed Tools can provide rapid snapshot of cost
reduction / improvement potential