Transcript Duct Sealing Savings: SEEM Modeling compared to ETO Evaluation Results Regional Technical Forum October 13, 2009

Duct Sealing Savings:
SEEM Modeling compared to ETO
Evaluation Results
Regional Technical Forum
October 13, 2009
• SEEM
SEEM Runs - Portland Weather - Electric Forced Air Furnace
Baseline Duct System
Duct R-Value
Supply
Return Duct
Prototype
UA
(Supply /
Leak
Leak
Sys
Return)
Fraction Fraction
Eff
SF 1344
345
4/4
0.15
0.10
76%
SF 2200
512
4/4
0.15
0.10
74%
SF 2688
576
4/4
0.06
0.10
91%
MH 924
247
20/infinite
0.15
0.00
79%
MH 1568
359
20/infinite
0.15
0.00
82%
MH 2352
504
20/infinite
0.15
0.00
82%
Prototype Weightings
Prototype (SF/MH)
Site Built Manuf Home
Small (1344/924)
75%
80%
Medium (2200/1568)
16%
16%
Large (2688/2352)
9%
4%
Average Size (sqft)
1,602
1,084
PTCS Duct System
Duct Seal
Supply
Return Duct
Savings
Leak
Leak
Sys
(kWh/yr)
Fraction Fraction
Eff
0.05
0.03
88%
1,298
0.05
0.03
86%
2,601
0.01
0.01
100%
1,215
0.05
0.00
93%
865
0.05
0.00
93%
1,133
0.05
0.00
93%
1,672
Weighted SEEM Savings (kWh/yr)
Portland
1,499
• ETO
ETO Savings - Converted to Electric FAF Savings
Savings Range
Gas FAF Eff Savings (kWh)
Low (46 therms)
75%
1,011
High (55 therms)
90%
1,451
Discussion
• With these assumptions, SEEM over-predicted savings
– but not by much
• However, the specific characteristics of the houses in the ETO study
are different than what was modeled in SEEM
–
–
–
–
Pre/Post duct system efficiency levels
Gas furnace efficiency
Average house size
Average house insulation levels
• SEEM model used cost-effective limit, ETO homes likely not quite there on
average
– making this adjustment would cause higher SEEM savings
– Climate
– Takeback
• What additional steps, if any, should be taken to calibrate SEEM
runs?
(The RTF uses it for a number of residential measures)