A geothermal heat pump is a heating and cooling system that takes advantage of the natural characteristics of shallow ground. Geothermal heat pumps, also known as GeoExchange, extract energy from the top 10 feet of the earth’s surface. The temperature in this area is usually between 50 and 61 degrees Fahrenheit (10 and 16 degrees Celsius). In the winter, a geothermal heat pump will use this ground temperature to heat the home, while in the summer, it will be used as a heat sink to cool the home.
The geothermal heat pump is made up of a loop that travels beneath the frost line, which is the point at which the ground temperature is no longer affected by the surface temperature. The loop is filled with a refrigerant that exchanges heat with the cooler or warmer ground. Depending on the season, the refrigerant is either warmed or cooled before returning to the appliance. This process, known as direct exchange, is most effective in maintaining a consistent temperature in an appliance or device. This system is frequently made of copper tubing or high-density polyethylene.
In both homes and businesses, two types of geothermal heat pumps are commonly used. Water-to-air systems can be used to replace forced-air furnaces and, in some cases, central air conditioning. The refrigerant is used to heat or cool air pushed through a geothermal heat pump. A water-to-water heat pump is used in radiators and underfloor heating systems. This works similarly to a boiler, heating water ducts that regulate a building’s temperature. Unfortunately, these systems are unable to provide cooling.
The first geothermal heat pumps were invented in the 1940s. Every year, about 50,000 new units are installed in the United States, according to the US Department of Energy. In most homes, these pumps are used to replace traditional heating and cooling systems. The cost of a geothermal heat pump per ton of capacity is around $2,500 USD. To control the temperature in most homes, a three-ton appliance is required. This means that the average consumer saves enough energy to pay for the installation and equipment over the course of five to ten years. The heat pump’s components have a 25-year lifespan, while the ground loop has a nearly 50-year lifespan.
A geothermal heat pump differs from traditional heating and cooling systems in that it does not rely on a fuel or chemical to keep the temperature constant. Combustion is used in furnaces and boilers to transfer heat. As a result, carbon emissions are produced, which can pollute the atmosphere. The average home emits 5,550 tons of carbon dioxide per year in heating and cooling, according to the US Energy Information Administration. That number is effectively nullified when using a geothermal heat pump.