.. _sphx_glr_api_gallery_thermodynamics_refrigeration:

Refrigeration
-------------

Refrigerators and heat pumps, and their Carnot limits.


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  <div id='sg-tag-list' class='sphx-glr-tag-list'></div>


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    <div class="sphx-glr-thumbnails">

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    <div class="sphx-glr-thumbcontainer" tooltip="In 1834 Jacob Perkins, an American engineer in London, patented a machine that evaporated ether at low pressure to absorb heat, compressed the vapour with a hand pump, and condensed it again under pressure. It was the first closed vapour-compression cycle, the cycle of nearly every refrigerator and air conditioner since. Its figure of merit is the coefficient of performance, the heat removed per unit of work, \mathrm{COP}_R = Q_c/W (~engineeringkit.thermodynamics.refrigeration_cop), and the second law bounds it by T_c/(T_h - T_c) (~engineeringkit.thermodynamics.carnot_cop_refrigerator). The example runs the ideal cycle with water as the refrigerant (R718, used today in some large chillers), because IAPWS-IF97 gives its properties.">

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  .. image:: /api/gallery/thermodynamics/refrigeration/images/thumb/sphx_glr_plot_01_perkins_vapor_compression_thumb.png
    :alt:

  :doc:`/api/gallery/thermodynamics/refrigeration/plot_01_perkins_vapor_compression`

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      <div class="sphx-glr-thumbnail-title">Perkins's vapour-compression refrigerator (1834)</div>
    </div>


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    <div class="sphx-glr-thumbcontainer" tooltip="In 1852 William Thomson, later Lord Kelvin, pointed out that the second law cuts both ways. A refrigerator run backwards would warm a building with heat drawn from the cold outside air, and the heat delivered would be many times the work spent. He proposed an air machine for it: compress outside air, let it give its heat to the rooms, then expand it. The figure of merit is \mathrm{COP}_{HP} = Q_h/W (~engineeringkit.thermodynamics.heat_pump_cop), at most T_h/(T_h - T_c) (~engineeringkit.thermodynamics.carnot_cop_heat_pump). Practical heat pumps had to wait for vapour compression and cheap electricity; they now heat millions of homes.">

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  .. image:: /api/gallery/thermodynamics/refrigeration/images/thumb/sphx_glr_plot_02_kelvin_heat_pump_thumb.png
    :alt:

  :doc:`/api/gallery/thermodynamics/refrigeration/plot_02_kelvin_heat_pump`

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      <div class="sphx-glr-thumbnail-title">Kelvin's heat pump (1852)</div>
    </div>


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    </div>


.. toctree::
   :hidden:

   /api/gallery/thermodynamics/refrigeration/plot_01_perkins_vapor_compression
   /api/gallery/thermodynamics/refrigeration/plot_02_kelvin_heat_pump