Chemical Engineering - Heat Transfer - Discussion

During mechanical vapour recompression, the vapour of an evaporator is recompressed to a higher pressure by means of a mechanically driven compressor. The recompressor therefore also operates as heat pump, adding energy to the vapour.

Contrary to the compression heat pump with circulating process liquid (i.e. A closed system, refrigeration cycle) the vapour recompressor can be considered as a special case of the compression heat pump because it operates as an open system.

After compression of the vapour and subsequent condensation of the heating steam, the condensate leaves the cycle. The heating steam (hot side) is separated from the vapour (cold side) by the heat exchange surface of the evaporator.