How does it work?
A mixture of water and antifreeze is circulated around a loop of pipes (a ground loop) buried in the ground. Heat from the ground is absorbed into the fluid and then passes through the heat exchanger into the heat pump. The fluid is then compressed, raising the temperature so that it can be used to cater for your heating and hot water needs.
Cooled ground-loop fluid will passes back into the ground where it absorbs further thermal energy, and the process begins again.