How it works
There are three important elements to a ground source heat pump: 

1.The ground loop
This is comprised of lengths of pipe buried in the ground, either in a borehole or a horizontal trench. The pipe is usually a closed circuit and is filled with a mixture of water and antifreeze, which is pumped around the pipe absorbing heat from the ground. The ground loop can be:
•Vertical, for use in boreholes
•Horizontal, for use in trenches
•Pound/Lake installation

2.A heat pump
In the same way that your fridge uses refrigerant to extract heat from the inside, keeping a ground source heat pump extracts heat from the ground, and uses it to heat your home.

3.Heat distribution system
This consists of under floor heating or radiators for space heating and in some cases water storage for hot water supply.