A geothermal system is also known as GeoExchange, ground-source heat pumps or an earth coupled system.

Outdoor air temperatures fluctuate with the seasons, but ground or groundwater temperatures a few feet beneath the Earth’s surface remain relatively constant throughout the year. At a depth of eight feet, the soil temperature in western Canada remains stable at approximately 5 C, (40 F).

Geothermal systems typically gather the temperature of the ground using pipes made of high-density polyethylene buried horizontally underneath the soil or a body of water or in vertical holes.  The pipes (also known as a loop) are extraordinarily durable but allow heat to pass through efficiently so that they don’t retard the exchange between the Earth and the fluid in the loop. 

These pipes are filled with an antifreeze/water solution that acts as a heat exchanger.  In the winter, fluids in the pipes absorb heat from the earth and carry it into the building.  In summer, the system reverses that process by taking heat from the building and depositing it to the cooler ground.

Electrically driven compressors and heat exchangers inside the building use a principle similar to a refrigerator or an air conditioner to cool the building.  In winter, the geothermal system reverses the flow of fluids and uses electricity to concentrate the Earth’s temperature and releases the heat inside the home at a higher temperature.

Geothermal systems do the work that ordinarily requires two or three appliances.  They can replace a furnace, an air conditioner and a boiler.

                           Down to Earth Renewable Technologies