Micro renewables - Heat pumps

Heat pumps are another form of solar energy technology. These use solar heat stored in the air (air source heat pumps), ground (ground source heat pumps) or water (water source heat pumps). They are used for space heating and in some instances, to pre-heat domestic hot water.

A heat pump system consists of an evaporator coil (for example laid in the ground in the case of a ground source heat pump) which then absorbs heat, and a compressor (driven by electricity) to pump the refrigerant in the coil from one place to another and to obtain the desired temperature.

Space to accommodate a ground source heat pump often limits their applicability in urban areas, whereas air source heat pumps do not have this same limitation. These are particularly suited to under floor heating which work at a lower temperature. Unlike other micro-generation systems, heat pumps have additional running costs associated with driving the pump. This section provides more information on heat pumps as small-scale ‘renewable’ energy technology.