Industrial Heat Pumps

 

Hybrid heat pump

Hybrid heat pumps, or compression resorption heat pumps, combine technologies of an absorption and compression heat pump. Hybrid heat pumps use a mixture of media, for example, NH3 and water. Due to changes in composition of the mixture caused by absorption and desorption, heat is extracted and emitted at a non-constant temperature. This temperature glide may lead to an increase in efficiency.

A hybrid heat pump consists of the following main components:
hybrid heat pump EN

  1. Desorber: in here waste heat is extracted by the mixture from the environment.
  2. Separator: the seperator separates water and Ammonia.
  3. Pump: the pump increases the water pressure.
  4. Compressor: Ammonia is compressed to a high pressure inside the compressor.
  5. Absorber: in here useful heat is released towards the environment.
  6. Expansion element: in here the pressure of the mixture is lowered.

A large temperature glide for absorption and desorption is favourable to decrease the ratio of compression inside a heat pump. As compared to the conventional mechanical heat pump ,an equal lift in temperature can be realised with a lower compression ratio when using a hybrid heat pump. As a result a higher COP can be reached. To increase the range of the temperature glide, the sizes of absorber and desorber should be increased as well (making them more expensive). Proper adjustment of the temperature glides and temperature ranges of the heat pump, is therefore essential to maximize efficiency. The use of media that can condensate or evaporate will lower the COP dramatically.

Advantages of hybrid heat pumps:

  • The condensation temperature is higher as compared to conventional compression machines. This is due to the saturation pressure that is much lower for a mixture than for a pure gaseous refrigerant flow.
  • In connection to what is mentioned above a large temperature lift is possible with a high COP.

Disadvantages of hybrid heat pumps:

  • Its technical complexity causes the hybrid heat pump to be expensive to install.
  • There is a limited number of manufacturers offering hybrid heat pumps.

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