The geothermal technology relies on the fact that the earth (beneath the surface) remains at a relatively constant temperature throughout the year, warmer than the air above it during the winter and cooler in the summer, very much like a cave. The geothermal system takes advantage of this by transferring heat stored in the earth or in ground water into a building during the winter, and transferring it out of the building and back into the ground during the summer. The ground, in other words, acts as a heat source in winter and a heat sink in summer.
How it works?
An energy-efficient heating and cooling alternative, the geothermal central water to water heat pump system moves heat from the ground to a building (or from a building to the ground) through fan coil and a series of flexible pipe "loops" containing water. In winter, heat from the relatively warmer ground goes through the heat exchanger into the building via fan coils. In summer, hot air from the building is pulled through the heat exchanger of fan coil into the relatively cooler ground.
Efficiency:
Central water to water heat pump systems complete with distributed fan coils are so efficient that they have proven to lower energy bills by up to 70% over traditional types of heating or distributed heat pump systems. This system is gaining wide acceptance for both residential and commercial buildings. The main benefit of geothermal based central water to water heat pump is they concentrate naturally existing heat, rather than by producing heat through the combustion of fossil fuels.
Video is better than a 1000 words:
This video shows how geothermal system generates clean, reliable, and renewable energy using the heat contained within the earth. It also demonstrate that geothermal energy can help us become better stewards of the earth and play or part in saving the earth from pollution.