08 January 2007

Fort Polk Installation Demonstrates Retrofi t Potential of Geothermal Heat Pumps


A recent independent study prepared for the U.S. Department of Energy by Oak Ridge National Laboratory (Hughes,
et al, 1998) demonstrates that geothermal heat pumps (GHPs) provide substantial benefi ts to the end user, the
electric utility industry and the environment. A comprehensive 4,003-home retrofi t project was conducted at Fort
Polk, Louisiana where the existing heating and cooling systems (560 gas furnace/electric air-conditioner systems
and 3443 air-source heat pump systems) were replaced by GHPs with desuperheater water heaters. In addition existing
incandescent lighting fi xtures were replaced by high-effi ciency fl uorescent or compact fl uorescent fi xtures,
and existing shower heads were replaced by low-fl ow shower heads. Evaluation of this massive retrofi t showed that
it reduced electrical consumption in the 4003 residences by 26 million kWh (33%) while altogether eliminating consumption
of 27,425,000 Mj of natural gas. Peak demand was reduced by 7.5 MW (43%), and the power factor was
increased from 0.52 to 0.62 . Emissions of CO2 have been reduced by an estimated 20,321,000 kg per year at the Ft
Polk site. The GHPs alone are credited with 66% of the electricity savings and all of the natural gas savings (Hughes
and Shonder, 1998) accounting for about 14,900,000 kg of the total annual CO2 emissions reduction