A system that transfers heat stored in the ground into your home. Heat is naturally stored in the ground, the ground source heat pump collects this latent heat and distributes it into your home’s heating system. The collectors can either be run horizontally through your land or dropped vertically, which is possibly less disruptive of your land.
Essentially it works like a refrigerator in reverse – the pump keeps the ambient temperature in the store lower that the temperature of the ground, drawing the latent heat from the collector into the converter which then raises the heat to approximately 35C (but can be higher). This source of heat is ideal for a low ambient heating system such as underfloor heating.
The system requires electricity from the national grid, and then typically produces 250-400% more energy than it uses. However, the electricity is probably being generated (here in SE UK) by plant burning about 3kWh of natural gas to deliver 1kWh of electricity to your door – so when you compare use of a GSHP to a modern gas condensing boiler (90% efficient) you will probably find that you are no better off in terms of cost or environmental impact.
They may be effective in Continental climates where, under a frost belt, summer heat awaits collection powered by a hydro-electric source (as in Scandinavia, Switzerland etc. where these systems are popular). Here where cold rain percolates downward, our summer rarely delivers extended heating periods and we would quite favour a good blast of heat in an unexpected blizzard, it seems unattractive. (And as a gardener I personally wait impatiently for the ground to heat up for spring plantings- FJH). We wait to be convinced.