BRE DG532/3 PDF

Electrically driven heat pumps are devices that may be used to generate heat for domestic hot water (DHW) and space heating. They achieve this by extracting heat from environmental sources such as the air or the ground. The heat is transferred to a refrigerant circuit where compression raises the fluid's temperature and useful heat is extracted, providing an alternative to conventional (eg gas- or oil-fired) heating systems.

Since heat pumps consume a lower amount of electrical energy than the heat energy they generate, and exploit heat from the environment, they are generally regarded as a low-carbon renewable energy technology, and the higher the ratio of heat output to electrical power consumed (known as the ‘coefficient of performance' or ‘COP'), the greater the efficiency.

Heat pump installations use a variety of heat sources and adopt a range of configurations to suit the user. Heat can be extracted from the outside air, from water sources such as lakes or rivers, from the ground (using a buried collector) or from adapted

sources such as exhaust air. The generated heat output is then distributed from the heat pump as warm air or as warm water for storage or for circulation in a heating system. Heat pumps generally operate most efficiently when delivering heat at lower temperatures than traditional sources such as gas- or oil-fired boilers, and may require the use of special low-temperature heating delivery systems such as underfloor heating or lowtemperature radiators that have larger heat exchange areas.