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Why ideal gases are not used in refrigerator?

  1. Apr 17, 2010 #1
    I read somewhere that a special fluid, called hydrofluorocarbon, is used in refrigerator. It carries hot temperature from the refrigerator and put it out. They says that it has a low specific heat capacity and low liquid/gas transition point (room temperature).
    Now my question is why ideal gas cannot be used for such a task?
     
  2. jcsd
  3. Apr 17, 2010 #2

    Borek

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    Staff: Mentor

    First of all - have you ever seen ideal gas?

    Especially gas that would be ideal around condensation point?

    What is a definition of ideal gas?
     
  4. Apr 17, 2010 #3
    Nice answer Borek! I appreciate it.
    But what if we assume noble gases such He and Neon or even natural air to be ideal (as we do always), can these be used in refrigerators?
     
  5. Apr 17, 2010 #4

    Borek

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    Staff: Mentor

    It all depends on the temperature range and economy. The way I see it any real gas can be used (as long as we are below critical temperature and above melting point), but for practical purposes we use gases that are safe and easy to work with. That means they must have boiling point around room temperature otherwise you need a very high pressures for condensation and it makes the refrigerator absurdly expensive.

    Note, that a lot depends on the temperature of the fridge content and surroundings.

    Still, ideal gas can't be used by its very definition. Ideal gas doesn't have intermolecular forces which play a very important role.
     
  6. Apr 17, 2010 #5
    thanks Borek. Now it makes more sense.
     
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