Introduction
Heat pumps are electrically-powered systems that tap the stored heat in the ground, water or air. The systems use the external environment’s relatively constant temperature to provide heating and hot water (and sometimes cooling) for buildings and industrial processes.
Although heat pumps are sometimes categorised as geothermal energy, they do not tap the heat from the earth’s core, but make use of solar energy - the effect of the sun warming the earth’s surface. Throughout the year the temperature of the soil a couple of metres or so down is 8°C to 13°C .
Heat pumps operate on the same principle as a domestic fridge but instead of extracting heat from the food in a fridge and expelling it into the room, heat pumps extract heat from outside and deliver useful heat to the building.
South west focus
There are approximately 150 heat pump installations in the south west, with over four MW of installed capacity. The vast majority are ground source heat pump schemes, although there are also a small number of air source and water source heat pumps.
- The Chy An Gweal sheltered-housing scheme in Cornwall was originally heated using an expensive solid fuel system. However, residents chose ground source heating (instead of oil) to replace their old coal boilers to provide affordable heating and hot water. Penwith Housing Association, which owns and manages the properties, oversaw the project. It involved installing 80m heat loops in boreholes in residents gardens and connecting 5kw heat pumps to the existing radiator system in each property.
- The Classroom of the Future - Space Classroom, and the Design Technology Wing - both at Camborne School in Cornwall, use ground source heat pumps. One delivers heating and cooling via a trenched based system and the other delivering heating via a borehole array. This is a UK-first for one site.
- Carrick Housing Association has installed 200 GSHPs in its social housing properties since 2006. Six air source heat pumps have been installed to evaluate the technology for possible use on a larger scale. Both types of system are being monitored to provide actual data for retro-fit applications.
- The Cotswold Water Park has two water source heat pumps, which draw energy from its lake.
