Solar energy disbursement
In the purest sense, geothermal systems use solar energy. The earth absorbs an amazing 48% of the sun's energy, leaving a fairly constant underground temperature between 45° and 70° F.
A water solution flows through pipes buried in the ground (ground loop system) absorbing heat from the earth in the winter and moving it to the geothermal system inside the house. Once there, the heat is condensed and transferred to the air that is circulated throughout the home, providing warmth when needed.
In the summer, the process is reversed, absorbing heat from the air inside the home, similar to how a refrigerator extracts heat from food to make it cool, and transfers that heat into the ground through the same loop system.