Suitability map for geo-exchange energy sources for heating and cooling, based on soil conditions. Geo-exchange systems for buildings or district energy plants may be feasible even in poor soil conditions, depending on design requirements and costs. Click here for more details. Credit: Adapted from Compass Resources Management Ltd. (2005) data by R. Tooke.

It uses the earth as a heat source (in the winter) or a heat sink (in the summer). This design takes advantage of the moderate temperatures in the ground to boost efficiency and reduce the operational costs of heating and cooling systems, and may be combined with solar heating to form a geosolar system with even greater efficiency. They are also known by other names, including geoexchange, earth-coupled, earth energy systems. The engineering and scientific communities prefer the terms "geoexchange" or "ground source heat pumps" to avoid confusion with traditional geothermal power, which uses a high temperature heat source to generate electricity. Ground source heat pumps harvest heat absorbed at the Earth's surface from solar energy. The temperature in the ground below 6 metres (20 ft) is roughly equal to the mean annual air temperature[2] at that latitude at the surface.

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