Ground source heat pumps (GSHPs) use pipes that are buried in the garden to extract heat from the ground. This heat can then be used to heat radiators, underfloor or warm air heating systems and hot water in your home. A ground source heat pump circulates a mixture of water and antifreeze around a loop of pipe, called a ground loop, which is buried in your garden. Heat from the ground is absorbed into the fluid and then passes through a heat exchanger into the heat pump. The ground stays at a fairly constant temperature under the surface, so the heat pump can be used throughout the year..
With the government grants that are available through the Renewable Heat Incentive the install costs can partially or fully re-couped. Finance can also be provided for UK residents as well as interest free loans through the Energy Saving Trust (Scotland Only)
How do they work?
Heat from the ground is absorbed at low temperatures into a fluid inside a loop of pipe (a ground loop) buried underground. The fluid then passes through a compressor that raises it to a higher temperature, which can then heat water for the heating and hot water circuits of the house. The cooled ground-loop fluid passes back into the ground where it absorbs further energy from the ground in a continuous process as long as heating is required.
Normally the loop is laid flat or coiled in trenches about two metres deep, but if there is not enough space in your garden you can install a vertical loop down into the ground to a depth of up to 100 metres for a typical domestic home.
Where do they work best?
Due to the cost of ground source they usually work best on larger houses however you do not need a big garden but ideally one that has access for digging machinery. Again it’s essential that your home is well insulated and draught-proofed for the heating system to be effective.
Renewable Heat Incentive
The Renewable Heat Incentive (the RHI) is a payment system in England, Scotland and Wales, for the generation of heat from renewable energy sources. The RHI operates in a similar manner to the Feed-in Tariff system, and was introduced through the same legislation – the Energy Act 2008. In the first phase of the RHI cash payments are paid to owners who install renewable heat generation on a quarterly basis over 7 years and in many instances can far outweigh the install costs. Combine this will the savings on heating bills and it gives an excellent return on investment.