Geothermal Heat Pumps: What They Are, How They Work, and Why They Are Worth Using

Abstract

Geothermal Heat Pumps, a.k.a. ?extended range, groundcoupled, water-source heat pumps?, operate in the low end of the earth heat spectrum, below 85°F (29°C). They heat and cool enclosed space and heat domestic water. Thermal output relative to grid power input is 300% to 500%, as electricity is used to run the heat pump but not to create or dissipate heat. Geothermal space conditioning and domestic water heating costs one-half (50%) to one-fifth (20%) as much as traditional technologies and fuels, while Life Cycle Costs are typically 30 to 60 percent less. Heat Pumps use proven vapor-compression refrigeration technology with no research, market or regulatory risks. Industry materials, practices and standards are fully established. Construction costs are about twice the least cost alternative for homes and -10% to +50% of commercial norms. End-use benefits include economic savings, enhanced power grid operation, carbon emission reduction, domestic safety and user comfort. Approximately two million 3-ton (i.e. house-sized) units have operated for up to 40 years without systemic problems. 1.5% of the annual North American HVAC market is a $2 billion industry.