Another term used to describe homes and buildings using geothermal heat pumps is that they are “Earth coupled” in that they are using the Earth as a heat source (in winter) and a heat sink in the summer.  The Earth coupled system uses a series of pipes, commonly called a “loop” which is buried in the ground near the building to be heated or cooled.  The loop can be buried either vertically or horizontally. It circulates a fluid (water, or a mixture of water and antifreeze) that absorbs heat from, or gives heat to, the surrounding soil, depending on whether the ambient air is colder or warmer than the soil.

Heat Pump Subsystem

For heating, a geothermal heat pump removes the heat from the fluid in the Earth connection, concentrates it, and then transfers it to the building. For cooling, the process is reversed.

Heat Distribution Subsystem

Conventional ductwork is generally used to distribute heated or cooled air from the geothermal heat pump throughout the building.

Residential Hot Water

In addition to space conditioning, geothermal heat pumps can be used to provide domestic hot water when the system is operating. Many residential systems are now equipped with desuperheaters that transfer excess heat from the geothermal heat pump’s compressor to the house’s hot water tank. A desuperheater provides no hot water during the spring and fall when the geothermal heat pump system is not operating; however, because the geothermal heat pump is so much more efficient than other means of water heating, manufacturers are beginning to offer “full demand” systems that use a separate heat exchanger to meet all of a household’s hot water needs. These units cost-effectively provide hot water as quickly as any competing system.