How Does a Geothermal Heat Pump Work?
The geothermal heat pump includes three principal components:
- Geothermal earth connection subsystem
- Geothermal heat pump subsystem
- Geothermal heat distribution subsystem.
Geothermal Earth Connection
Using the Earth as a heat source/sink, a series of pipes, commonly called a "loop," is
buried in the ground near the building to be heated and cooled. The loop can be buried
either vertically or horizontally. A pump circulates a fluid (water, or a mixture of water
and antifreeze) that absorbs heat from, or relinquishes 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 provide domestic hot water when the system
is operating. Many residential systems are 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.