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Field Experience with Ground-Source Heat Pumps in Affordable Low Energy Housing. Daniel Ellis President ClimateMaster, Inc. Oklahoma City, U.S.A. dellis@climatemaster.com www.climatemaster.com. Non-profit Christian housing ministry Founded in 1976 Has built 250,000 homes world-wide
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Field Experience with Ground-Source Heat Pumps in Affordable Low Energy Housing Daniel Ellis President ClimateMaster, Inc. Oklahoma City, U.S.A. dellis@climatemaster.com www.climatemaster.com
Non-profit Christian housing ministry • Founded in 1976 • Has built 250,000 homes world-wide • Providing over 1 million people with safe, decent, affordable shelter • 3rd largest private homebuilder in USA • 5,000 homes per year in USA • Plus 20,000 homes per year in other countries • Not a give-away program • Volunteer labor and donations reduce costs • Homeowners provide down-payment, interest-free mortgage payments, and sweat equity
COHFH Builder’s “Blitz” Week (June 2006) (1/3) Monday 8:00am slab with geothermal bore Friday 4:00pm owner move-in 10 professional home builders each sponsored a separate houseand constructed it from start to finish in 5 days!
COHFH Builder’s “Blitz” Week (June 2006) (2/3) SO HOW DID THEY DO IT? Brute Force!
Ongoing Partnership Formed in 2007 • COHFH, ClimateMaster, and OGE (electric utility) partner to make all COHFH homes low energy • Higher initial costs could not be passed on to homeowners due to COHFH cash flow considerations • COHFH is the mortgage lender • ClimateMaster and OGE agree to share initial cost difference over standard construction • Act of corporate stewardship • Gift of reducing energy consumption provides long-term benefits to the homeowners and to our environment • Provides valuable experience in unexplored segment of housing market
Partnership Goals • Install GHP systems in all COHFH homes • Reduce total energy demand of these homes to maximum reasonable extent • Using cost-effective and generally available measures • Track the energy consumption of the homes • Collect monthly utility meter data to establish a baseline of actual performance • Install a proportion of “smart” recording meters to collect detailed data on electric demand profiles • Demonstrate potential for zero energy homes • By integrating grid-tied solar PV system • Initial goal of zero peak demand and zero net GHP energy • later goal of zero net total energy • Utilize project as a market transformation tool • Large-scale demonstration of affordable, low-energy housing • Raise public and construction trade awareness, generate spin-off projects with other HFH affiliates, and attract additional COHFH funding
Evolution of COHFH Homes Standard Gas House Energy Use: 95 MMBTu Energy Cost: $1,739 CO2 Emissions: 25,460 lbs Low Energy GHP + PV House Energy Use: 19 MMBtu Energy Cost: $522 CO2 Emissions: 9,825 lbs
Energy Consumption Estimates • Benchmark hot water, lighting, and appliance loads for standard houses estimated using NREL methodology (Hendron, et al. 2004) • CFL lighting and Energy Star appliance adjustments made for low energy houses • Heating and cooling energy estimated using GeoDesigner software from ClimateMaster • Solar PV contribution estimated using PVWATTs software from NREL
Source Energy and C02 Emission Estimates • US national average factors for electricity and natural gas obtained from NREL (Deru and Torcellini 2006) • Includes power plant conversion, transmission, and distribution losses for electricity • Includes pre-combustion effects associated with extracting, processing, and delivering primary fuels to point of conversion in power plant • For natural gas includes both pre-combustion effects and on-site combustion emissions
Planned Future Improvements • Advanced GHP with variable capacity and integrated full-condensing hot water modes • Zero-energy home using larger grid-connected PV array
Return on Investment vs. Standard Gas Home Annual Fuel Escalation Rate 2%
Conclusions • Total site energy consumption reduction of 50-75% • Using GHPs and low-energy construction techniques • 50% reduction in metered energy was achieved using GHPs alone • 1,100 tons of annual CO2 emissions avoided • Collective contribution of 240 low energy GHP homes in Hope Crossing as compared to standard gas homes • Not including the contribution of solar PV systems • Low energy GHP homes are cost-effective • Even at standard builder pricing, the ROI is over 15% after tax • Concepts employed are generally available • Low energy demand makes solar PV more viable • Small array on first two PV homes will reduce peak demand to near zero on hot summer afternoons and produce enough annual power to completely operate the GHP system • Zero net energy is feasible, but not yet cost-effective