hvac and dhw system conversion cost and energy use assumptions for direct use of natural gas...
TRANSCRIPT
HVAC and DHW System Conversion Cost and Energy Use Assumptions for Direct Use of Natural Gas Analysis
September 28, 2010
Incremental Cost of Conversion Needs to Reflect Changing Federal Standards
US DOE must adopt new efficiency standards for furnaces, central AC and heat pumps by May/June 2011. These standards would take effect in 2013 for gas furnaces and 2015 for Central AC and Heat Pump
DOE adopted new standards for gas and electric water heaters effective April 16, 2015
New Water Heater Standards
Electric– 55 gallon & smaller tanks =>EF 95– Above 55 gallon tanks => EF 2.0
Gas (storage)– 55 gallon & smaller tanks => EF 62– Above 55 gallon tanks => EF 75
Gas (tankless) => EF 82
Consensus Recommendation on HVAC Equipment Efficiency Standards
DOE has been petitioned to adopt a consensus recommendation on standards for gas furnaces, heat pumps and central AC
Consensus recommendation from AHRI (HVAC manufacturer’s trade association) and ACEEE, NRDC, ASE, NEEP, CEC, ASAP & NPCC
System Type Minimum Efficiency
Split System Central AC
13 SEER
Gas Furnace 90% AFUE
Split System Heat Pump
14 SEER/8.2 HSPF
Packaged HP 14 SEER/8.0 HSPF
Packaged AC 14 SEER
Gas-Pack 14 SEER/81% AFUE
Oil Furnace 83% AFUE
Implications for Base Case Efficiency
System Base Case Efficiency in Current Model
Revised Base Case Efficiency
Gas Furnace 80% AFUE 90% AFUE
Heat Pump HSPF 7.7/SEER 13
HSPF 8.2/SEER14
Gas Storage DHW
EF 59 55 gal & below EF 62>55 gal. EF 75
Gas TanklessDHW
EF 80 EF82
Electric Storage EF 90 55 gal & below EF 95>55 gal. EF 2.0
Revised Baseline Conversion Cost Estimates HVAC Systems
$0
$1,000
$2,000
$3,000
$4,000
$5,000
$6,000
HSPF 8.2/SEER14 - 2.5 Ton
HSPF 8.2/SEER14 - 3.0 Ton
AFUE 90/ SEER13 - ~60kBtu/hr
AFUE 90/ SEER13 - ~80kBtu/hr
Low Most Likely High
Revised Baseline Conversion Cost Estimates HVAC Systems (No Existing Air Conditioning)
$0
$1,000
$2,000
$3,000
$4,000
$5,000
$6,000
HSPF 8.2/SEER14 - 2.5 Ton
HSPF 8.2/SEER14 - 3.0 Ton
AFUE 90 w/oCAC - ~60
kBtu/hr
AFUE 90 w/oCAC - ~80
kBtu/hr
Low Most Likely High
Issue: How should we treat “added CAC service” from heat pump?
Revised High Efficiency Conversion Cost Estimates
$0
$1,000
$2,000
$3,000
$4,000
$5,000
$6,000
$7,000
AFUE 92/SEER 14 -
~60kBtu/hr
AFUE 92/SEER 14-
~80kBtu/hr
HSPF8.5/SEER14 - 2.0
Ton
HSPF8.5/SEER14 - 3.0
Ton
HSPF9.0/SEER14 - 2.0
Ton
HSPF9.0/SEER14 - 3.0
Ton
Low Most Likely High
Revised Conversion Cost for Water Heating Systems*
$0 $500 $1,000 $1,500 $2,000 $2,500 $3,000 $3,500
Electric Storage -EF 0.95
Electric Storage -EF 2.0
Gas Storage - EF0.62
Gas Storage - EF0.75
Gas Tankless - EF0.82
Low Most Likely High
*Not including gas service extension or electrical panel size increase
Tank Size Distribution Assumptions
0%5%
10%15%20%25%30%35%40%45%50%
30 40 50 66 75 119
Tank Size (Nominal Capacity - gallons)
Mark
et Share
Electric StorageGas Storage
Approximately 10% of electric water heaters and 4% of gas water heaters are greater than 55 gallons, hence are subject to the EF 2.0 and EF 75 standards.
Energy Use Implications of New Standards
Higher efficiency requirements for replacement water heaters, furnaces & heat pumps establish lower “baseline use” for replacement of existing systems– Example:
» Prior assumptions - Consumer can replace existing 66 gal. electric water heater with EF-0.88 electric water heater or convert to EF-0.54 gas water heater. Base case electric use =
» Revised assumptions - Consumer can replace existing electric water heater with EF-2.0 electric water heater or convert to EF-75 gas water heater.
Revised Energy Use Methodology
Baseline home prior to conversion originally modeled “as found” (i.e., partially weatherized)
Revised approach models conversion options (gas or electric) as “last measure in” (i.e., fully weatherized) consistent with 6th Plan and RTF methodology for other retrofit measures
Space Conditioning Estimates
Source: SEEM calibrated simulation results from weatherization and heat pump conversion/upgrade analysis
Gas consumption assumes same input assumptions as electric forced air, adjusted for furnace conversion efficiency (AFUE 90%)
Climate = PNW Weighted Average– Should we do each heating zone analysis
after initial results are reviewed?
Home Sized Revised to Reflect Correlation with System Types and Basements*
System Type Basement No Basement
Electric FAF 2,982
2,160
Zonal 2,573
1,540
Heat Pump 2,118
2,298
All 2,438
1,693
*Source: Analysis of Super Good Cents sub-metered data – N= 603 homes
Base Case Single Family Energy Use Assumptions – Space Conditioning
System Type Average House Size Representative Model
Annual Heating Energy Use -
Electricity (kWh)
Annual Cooling Energy Use -
Electricity (kWh)
Annual Energy Use - Gas
(Mbtu)
Electric Zonal 1600Weighted Average 1344 sq.ft. and 2200 sq.ft. 7,743
Electric Zonal - Basement 2688 2688 sq,ft. Basement Prototype 10,499
Electric FAF w/o CAC 2200 2200 sq.ft. prototype 13,473
Electric FAF w/o CAC - Basement 2688 2688 sq,ft. Basement Prototype 10,910
Electric FAF w/ CAC 2200 2200 sq.ft. prototype 13,473 674
Electric FAF w/ CAC - Basement 2688 2688 sq,ft. Basement Prototype 10,910 393
Heat Pump 2200 2200 sq.ft. prototype 8,492 603
Heat Pump - Basement 2688 2688 sq,ft. Basement Prototype 6,348 351
Gas FAF w/o CAC 2200 2200 sq.ft. prototype 51
Gas FAF w/o CAC - Basement 2688 2688 sq,ft. Basement Prototype 41
Gas FAF w/ CAC 2200 2200 sq.ft. prototype 674 51
Gas FAF w/ CAC - Basement 2688 2688 sq,ft. Basement Prototype 393 41
Base Case Multifamily Energy Use Assumptions – Space Conditioning
Prototype System Type
Heating Use (kWh/yr)
Heating Use (MBtu/yr)
Cooling Use (kWh/yr)
MF - 1050 sq.ft. Electric FAF w/o CAC
6,660
MF - 1050 sq.ft. Electric FAF w/ CAC
6,660
485
MF - 1050 sq.ft. Electric Zonal
6,228
MF - 1050 sq.ft. Heat Pump
4,939
436
MF - 1050 sq.ft. Gas FAF w/o CAC 25
MF - 1050 sq.ft. Gas FAF w/ CAC 25
485
Base Case Water Heating Assumptions
System Type Representative Model
Total Installed
Cost
Annual Maintenance
Cost
Annual Energy Use -
Electricity (kWh)
Annual Energy Use - Gas
(Mbtu)SF - Electric Storage <= 55 gal 50 gal EF 0.95 – Electric Resistance $ 751 $ 4.01 3,355
SF - Electric Storage > 55 gal 66 gal EF 2.00 - Heat Pump Water Heater $ 2,176 $ 8.89 1,594
SF - Gas Storage <= 55 gal 40 gal EF 0.63 EF - Standing Pilot $ 1,178 $ 12.36
- 17.69
SF - Gas Storage > 55 gal 66 gal EF 0.77 EF – Condensing w/ power vent $ 3,178 $ 14.79 128 13.69
SF - Gas Tankless Variable output EF 0.82 Electronic Ignition, Power Vent, Improved HX $ 2,380 $ 66.88 30 13.16
MF - Electric Storage <= 55 gal 40 gal EF 0.95 Electric Resistance $ 617 $ 4.01 2,277
MF - Gas Storage <= 55 gal 30 gal EF 0.63 EF - Standing Pilot $ 1,071 $ 14.79
- 12
MF - Gas TanklessVariable output 0.82 EF Electronic Ignition, Power Vent, Improved HX $ 2,380 $ 66.88 28 8.91
ETO Avista RTF-Low RTF-Most Likely RTF-High RTF-Average $-
$500
$1,000
$1,500
$2,000
$2,500
$3,000
$3,500
$4,000
AFUE 92 Furnace Cost
HSPF 8.5/SEER 14 - 2.0 Ton HSPF 8.5/SEER 14 - 3.0 Ton HSPF 9.0/SEER 14 - 2.0 Ton HSPF 9.0/SEER 14 - 3.0 Ton $-
$1,000
$2,000
$3,000
$4,000
$5,000
$6,000
$7,000
Heat Pump Cost
RTF-Low
RTF-Most Likely
RTF-High
RTF-Mean
ETO-Mean
ETO Gas Tankless Water Heater Cost
80 81 82 83 84 85 86 87 88 90 92 93 94 95 96 97 98 $-
$1,000
$2,000
$3,000
$4,000
$5,000
$6,000
Retrofit Duct System Cost
Style Size (sq.ft.) Cost/sq.ft.
Duct System Cost
Ranch 1344 $1.30 $1,747 2-Story 2200 $1.50 $3,300 1-Story w/Basement 2688 $1.00 $2,688