Field Experience with Ground-Source Heat Pumps in Affordable Low Energy HousingDaniel EllisPresidentClimateMaster, Inc.Oklahoma City, U.S.A.

dellis@climatemaster.comwww.climatemaster.com

Non-profit Christian housing ministryFounded in 1976Has built 250,000 homes world-wideProviding over 1 million people with safe, decent, affordable shelter3rd largest private homebuilder in USA5,000 homes per year in USAPlus 20,000 homes per year in other countriesNot a give-away programVolunteer labor and donations reduce costsHomeowners provide down-payment, interest-free mortgage payments, and sweat equity

COHFH Builders Blitz Week (June 2006)(1/3)Monday 8:00am slab with geothermal boreFriday 4:00pm owner move-in10 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 Builders Blitz Week (June 2006)(2/3)Brute Force!

COHFH Builders Blitz Week (June 2006)(3/3)

Ongoing Partnership Formed in 2007COHFH, 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 considerationsCOHFH is the mortgage lender

ClimateMaster and OGE agree to share initial cost difference over standard constructionAct of corporate stewardshipGift of reducing energy consumption provides long-term benefits to the homeowners and to our environmentProvides valuable experience in unexplored segment of housing market

Partnership GoalsInstall GHP systems in all COHFH homes

Reduce total energy demand of these homes to maximum reasonable extentUsing cost-effective and generally available measures

Track the energy consumption of the homesCollect monthly utility meter data to establish a baseline of actual performanceInstall a proportion of smart recording meters to collect detailed data on electric demand profiles

Demonstrate potential for zero energy homesBy integrating grid-tied solar PV systemInitial goal of zero peak demand and zero net GHP energylater goal of zero net total energy

Utilize project as a market transformation toolLarge-scale demonstration of affordable, low-energy housingRaise public and construction trade awareness, generate spin-off projects with other HFH affiliates, and attract additional COHFH funding

Evolution of COHFH HomesStandard Gas House

Energy Use: 95 MMBTuEnergy Cost: $1,739CO2 Emissions: 25,460 lbsLow Energy GHP + PV House

Energy Use: 19 MMBtuEnergy Cost: $522CO2 Emissions: 9,825 lbs

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 EstimatesBenchmark 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 C02 Emission EstimatesUS 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 ImprovementsAdvanced 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 HomeAnnual 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 avoidedCollective contribution of 240 low energy GHP homes in Hope Crossing as compared to standard gas homesNot including the contribution of solar PV systemsLow energy GHP homes are cost-effectiveEven at standard builder pricing, the ROI is over 15% after taxConcepts employed are generally availableLow energy demand makes solar PV more viableSmall 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 systemZero net energy is feasible, but not yet cost-effective

Thank You!