Field Experience with Ground-Source Heat Pumps in Affordable Low Energy Housing

1. 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

2. 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

3. 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!

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

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

6. 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

7. 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

8. 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

9. COHFH Housing Characteristics(1/2)

10. COHFH Housing Characteristics(2/2)

11. COHFH Hope Crossing Project (1/4)

12. COHFH Hope Crossing Project (2/4)

13. COHFH Hope Crossing Project (3/4)

14. COHFH Hope Crossing Project (4/4)

15. Average Metered Energy Consumption

16. Derivation of Htg & Clg Energy Consumption

17. Average Metered Energy Costs

18. 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

19. Estimated Site Energy Consumption by End Use

20. Validation of Energy Consumption Estimates

21. 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

22. Estimated Total Energy Consumption and Emissions

23. Planned Future Improvements • Advanced GHP with variable capacity and integrated full-condensing hot water modes • Zero-energy home using larger grid-connected PV array

24. Estimated Site Energy Consumption by End Use

25. Additional Investment and Annual Energy Cost Savings

26. Return on Investment vs. Standard Gas Home Annual Fuel Escalation Rate 2%

27. 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

28. Thank You!