Ground source energy systems consist of three main parts:
Heat pump – found inside the building and uses compression to either create heating or cooling for the building. The heat pump is connected to the ground-coupled heat exchanger (GHX) and circulates a fluid through the GHX in order to store/retrieve energy.
Ground-coupled heat exchanger (GHX) – underground piping that is in contact with the earth in order to store or retrieve energy. These are either closed or open loop underground piping systems.
Distribution system– dispenses the heating or cooling throughout the building. (A water to air system would used forced air to distribute warm/cool air required to create a comfortable living area. A water to water system would use radiant heat for warming flooring, or to create hot water to store in tanks.)
Putting it all together
This four-minute video shows you how ground source energy works with different types of loop systems: