By Jori Fahrenfeld
What is a Geothermal Heat Pump?
Geothermal heat pumps (GHP), also known as ground-source heat pumps, can heat, cool, and even supply hot water to a home by transferring heat to or from the ground.
GHPs take advantage of these constant below ground temperatures to heat homes in the winter and cool them in the summer.
This ground temperature is warmer than the air above it during the winter and cooler than the air in the summer. The GHP takes advantage of the constant subsurface temperatures by exchanging heat with the earth through a ground heat exchanger.
The ground provides a type of thermal energy storage, which allows GHPs to act as a heat sink—absorbing excess heat during summer, when surface temperatures are relatively higher—and as a heat source during the winter, when surface temperatures are lower. This increases efficiency and reduces the energy used to heat and cool homes
There are options to consider when selecting a GHP system, including closed- or open-loop designs. The majority (85%) of GHPs in the United States use ground heat exchangers to circulate fluid through a closed-loop design.
A Geothermal Heat Pump System is comprised of:
- An underground heat collector
- A heat pump
- A heat distribution subsystem
Underground Heat Collector: the loop can be buried either horizontally or vertically. The loop circulates a fluid that either absorbs or deposits heat to the surrounding soil, depending on whether the outside air is warmer or colder than the soil.
Heat Pump: when ambient temperatures are warmer than the ground, the heat pump removes heat from the building and deposits it underground. When the ambient temperatures are colder than the ground, the geothermal heat pump will remove heat from the collection fluid and transfers it to the building.
Heat Distribution Subsystem: conventional ductwork can be used to distribute heated or cooled air from the geothermal heat pump throughout the building.