A geothermal system draws on the largest and most readily available source of energy available – the earth.
Outdoor temperatures fluctuate, but five feet (or 1.5 meters) below the earth, ground temperatures remain constant – even in winter – at around 10°C (50°F). This ground temperature is warmer than the air above during the winter and cooler in the summer. A geothermal heat pump (GHP) takes advantage of this by exchanging heat with the earth through a ground heat exchanger. The heat pump then increases the temperature to normal home levels. This means that you have a steady supply of heat to keep you in comfort, even in the depths of the coldest winter.
Best of all, geothermal is a free source of energy and environmentally-friendly too.
How is a geothermal system installed?
The free energy has only to be moved from the ground into your home. This is done by pumping an environmentally-friendly fluid through horizontal or vertical underground pipes (closed loop). In the winter, the fluid absorbs the heat from the ground and, now warmed up, transfers it to the heat pump in your home. The heat absorbed by the fluid from the solar-heated ground is extracted from it by the heat pump, and the now-chilled fluid is circulated through a heat exchanger over and over again to extract more heat from the earth.
In the summer, the heat transfer process is reversed. The fluid in the pipes leaves the house in a warm state, but after circulating underground, is cooled as the pipes exchange heat with the cooler earth.
1Source: Quest Geothermal