Ground source heat pumps utilise geothermal energy to provide heating for a home or other building, or alternatively to provide hot water. (For more information on Geothermal Energy - Click Here). A few metres beneath the surface of the earth the temperature is a constant 12°C all year round. It is this heat that ground source heat pumps use by converting and transferring the heat into a building usually to heat radiators or under-floor heating.
Ground source heat pumps consist of a ground loop and the heat pump itself. The ground loop is basically a pipe filled with water and antifreeze which is pumped around a closed circuit absorbing the ground’s heat. This system, of course, requires a large enough outside area belonging to the property, although there are different pipe systems available including a bore hole variety.
Once the water has been heated the evaporator part of the ground source heat pump takes the heat from the water and it is passed into the compressor. This moves refrigerant around the heat pump and compresses the gaseous refrigerant to the temperature required for the heat distribution circuit (the radiators or under-floor heating). A condenser then gives up the heat to a hot water tank which feeds the distribution system (or, in some cases, provides hot water for use in the property).
The cost of a typical ground source heat pump system is approximately £7,000 to £13,000, and this type of heating provision is most cost effective where mains gas is unavailable. Grants are available for homeowners from the low carbon buildings programme up to a maximum of £1200 or 30% of the total cost.
For more information on ground source heat pumps visit www.est.org.uk or take a look at www.lowcarbonbuildings.org.uk for details of the available grants.
Source: www.est.org.uk, www.lowcarbonbuildings.org.uk 2009
