Electrical and engine driven heat pumps

Much of the energy used for domestic, commercial and industrial purposes is to provide efficient and effective heating of conditioned spaces and for specialist niche applications in process heat systems. Vapour compression heat pumps driven by electric motors or engines provide the real capability of upgrading low temperature sources of ambient and waste heat to match the desired load temperatures in such heating applications. Major sources of ambient heat stem from the storage of solar energy in the ground, in lakes and rivers, and in atmospheric air. Heat pumps can therefore be used to effectively harness indirectly the daily solar radiation input. In addition, many industries have major sources of waste low-grade heat in the form of air or water discharged from the industrial process heat stream. Heat pumps are generally formally classified as air source, ground source or water source units, although there has also been considerable interest recently in hybrid units combining the attributes of two or more of these specific types mentioned above.