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Heat pumps and refrigerators
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**Heat pumps** and **refrigerators** are *thermal energy converters*: they use mechanical energy to move thermal energy from a cold source to a hot sink.

The *Carnot heat generator* (seen in section :ref:`Sec:chap2:CarnotHeatGen`) presents the maximum thermal efficiency but *Real heat generators* are generally not exchanging thermal energy using isothermal transformations.

This chapter treats:

  1) Gas heat pump and refrigeration cycle (reverse Brayton cycle)
  2) Vapor compression heat pumps and refrigerators

.. toctree::
  :maxdepth: 1
  :caption: Contents:

  chap5_1GasGenerator
  chap5_2VaporCompMachines