Geothermal Heat Pump Design

When describing a heat pump it is a machine that transfers heat both to and from a source by employing a refrigeration cycle. Although heat normally flows from higher to lower temperatures, a heat pump reverses that flow and acts as a “pump” to move the heat. A heat pump can be used both for space heating in the winter and for cooling in the summer. In the refrigeration cycle, a refrigerant is compressed then expanded as a vapor to absorb and remove heat. The heat pump transfers heat to a space to be heated during the winter period and by reversing the operation, extracts or absorbs heat from the same space to be cooled during the summer period.

A geothermal heat pump is a heat pump that draws heat from the ground water, instead of air. In the winter, a geothermal heat pump transfers heat from the ground water to provide space heating. In the summer, the heat transfer process is reversed by the ground or ground water absorbing heat from your home and cools the air. A geothermal heat pump benefits from nearly constant ground water temperatures over most of the continental United States, regardless of outside air temperatures. These temperatures are higher on average than winter air temperatures and lower on average than summer temperatures.

The geothermal heat pump does not have to work as hard to extract heat from or move heat to the ground water at a moderate temperature as from the cold air in winter or to the hot air in summer. The energy efficiency of a geothermal system is thus higher than that of a conventional heat pump.

Depending on the size of your property your contractor has several options to tap the heat source of ground and ground water. One efficient method is a series of drilled water well looped together to draw heat and dispose of heat. Many regions are requiring retention ponds for water conservation that can also be used to provide an excellent source of heat.

A geothermal heat pump can also provide hot water using a device called a desuperheater” that transfers excess heat from the heat pump’s compressor to a hot water tank. In the summer, hot water is provided free and in the winter, water heating costs are cut approximately in half.

Although residential geothermal heat pumps are generally more expensive to install than air-source heat pumps they can have a 2 to 5 year pay back. Unlike air-source heat pumps,they can operate without a energy guzzeling backup heat source. You can do your part by reducing energy consumption and emissions of carbon and other air pollutants.