Although we may not know it, heatpumps are very familiar to us – fridges and air conditioners are two examples. Groundsource heatpumps (GSHP) transfer heat from the ground into a building to provide space heating and, in some cases, to pre-heat domestic hot water. For every unit of electricity used to pump the heat, 2-4 units of heat are produced.
There are three important elements to a groundsource heatpump system:
- The Ground Loop. This is comprised of length 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 round the pipe absorbing heat from the ground.
- A Heatpump. This has three main parts – the evaporator, compressor and heat exchanger. The evaporator is usually a ground loop which takes the heat from the ground with the use of refrigerants. The compressor moves the refrigerant round the heatpump and compresses the gaseous refrigerant to the temperature needed for the heat distribution circuit. The heat exchanger gives up heat to a hot water tank which feeds the distribution system.
- The heat distribution system. Consisting of underfloor heating or over sized radiators for space heating and in some cases, water storage for hot water supply.
© Energy Saving Trust 2008