There are 3 points of connection in a ground source loop, the earth, the pump, and the distribution system.
At the ground level, there are a series of connected pipes that are buried underground near the building. The fluid that circulates in the loop absorbs or relinquishes heat to the surrounding ground.
The heat pump works both to heat and cool. To heat, the pump removes the heat from the circulating liquid, concentrates it, and then transfers it to the building. To cool, the pump removes heat from the air in the building, concentrates it, and then transfers it back to the circulating liquid.
Distribution systems can be of various forms including: forced air through conventional ductwork (pipes, vents), hydronic (water), radiators, and radiant.