Geothermal energy is considered a renewable resource. Land-based heat pumps and direct-use geothermal technologies serve heating and cooling applications, while deep and improved geothermal technologies generally take advantage of a much deeper and higher temperature geothermal resource to generate electricity.
Geothermal heating and coolingmake that vision a reality. Geothermal air conditioning (heating, ventilation and air conditioning) brings a building in harmony with the land below, taking advantage of underground temperatures to provide heating in winter and cooling in summer.
But what does an air conditioner do to cool a house? It uses heat, except that you move it out of the house. All a geothermal system has to do to provide cooling to a home is reverse the direction in which heat moves. Instead of extracting heat from the ground with its loops, it removes heat from the house and deposits it in the ground. In other words, a geothermal air conditioning system uses the ground as a heat sink.
During the summer, the geothermal system draws heat from the air in your home and transfers it to the ground. However, the efficient performance of a geothermal heat pump means that it will amortize your installation with savings in just a few years. The heat pump can also work in reverse, moving heat from the ambient air of a building to the ground, thus cooling the building. Steam resources that are economical to exploit are currently limited to regions with high geothermal activity, but research is underway to develop improved geothermal systems with much deeper wells that take advantage of the Earth's natural temperature gradient and can be built anywhere.
Geothermal heat pumps usually last 20 to 25 years, and ground loops installed in the yard can last more than 50 years. The geothermal heat pump uses cold water returning from the ground to create a cold, dehumidified air conditioner for your home. The heat pump circulates a heat-carrying fluid, sometimes water, through pipes to move heat from one point to another. Geothermal heating and cooling systems take advantage of stable subsurface temperature through a piping system, commonly referred to as a “circuit”.
It is true that installing a geothermal system costs more than a standard heat pump and requires sufficient space in the house. Water from direct geothermal systems is hot enough for many applications, such as large-scale pool heating; on-demand heating, cooling and hot water for buildings of most sizes; district heating (i.e., ClimeMaster geothermal heating and cooling systems are 400 to 600% efficient and can reduce heating, cooling and hot water costs by up to 70%). Heat pumps can meet space heating and cooling needs almost anywhere in the country, and can also be used for domestic hot water applications.