Field Experience with Ground-Source Heat Pumps in Affordable Low Energy Housing Daniel Ellis President ClimateMaster, Inc. Oklahoma City, U.S.A.

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 3 rd 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 08:00 slab with GHXFriday 16:00 owner move-in 10 professional home builders each sponsored a separate house and constructed it from start to finish in 5 days!

SO HOW DID THEY DO IT? COHFH Builder’s “Blitz” Week (June 2006) (2/3) Brute Force!

COHFH Builder’s “Blitz” Week (June 2006) (3/3)

Ongoing Partnership Formed in 2007 COHFH, GHP manufacturer, and local 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 GHP manufacturer and electric utility 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: 252 kWh/(m 2 · yr) Energy Cost: $1,739 CO 2 Emissions: 105 kg/(m 2 · yr ) Low Energy GHP + PV House Energy Use: 52 kWh/(m 2 · yr) Energy Cost: $522 CO 2 Emissions: 41 kg/(m 2 · yr)

COHFH Housing Characteristics (1/2)

COHFH Housing Characteristics (2/2)

COHFH Hope Crossing Project (1/4)

COHFH Hope Crossing Project (2/4)

COHFH Hope Crossing Project (3/4)

COHFH Hope Crossing Project (4/4)

Average Metered Energy Consumption

Derivation of Htg & Clg Energy Consumption

Average Metered Energy Costs

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

Estimated Site Energy Consumption by End Use

Validation of Energy Consumption Estimates

Source Energy and C0 2 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

Estimated Total Energy Consumption and 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

Estimated Site Energy Consumption by End Use

Additional Investment and Annual Energy Cost Savings

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 CO 2 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

Thank You!