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Carnot Cycle

  1. Aug 29, 2011 #1
    Hi

    From http://en.wikipedia.org/wiki/Carnot_cycle

    "Reversible isothermal expansion of the gas at the "hot" temperature, TH (isothermal heat addition). During this step the expanding gas makes the piston work on the surroundings. The gas expansion is propelled by absorption of quantity Q1 of heat from the high temperature reservoir."

    I was wondering why the work done on the surroundings at this stage does not count toward the total work output of the cycle and why it is not used?

    Thanks
     
  2. jcsd
  3. Aug 30, 2011 #2
    It does.

    In fact, from the first law of thermodynamics, you can make Heat = Work + Delta U, though as it is a cycle and U is a state variable, Delta U in the cycle is null, so the heat transferred is equal to work.
     
  4. Aug 30, 2011 #3
    Hi, thanks for the response

    What about for a boiler? A boiler in a heat engine operating a Carnot cycle does not have a piston (it is rigid), in this case, although it is also responsible for Process 1-2 in a Carnot cycle it does no work right? Also, how does a rigid boiler maintain isothermal heat transfer?

    Thanks
     
  5. Aug 31, 2011 #4
    does the steam from the boiler go anywhere and do anything?
     
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