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Heat Pumps

  1. Apr 19, 2009 #1
    1. The problem statement, all variables and given/known data
    The question asks us to advise the company on a heat pump (and give reasons) which is claimed to deliver 1500J to a room at 280K by consuming 50J of work per cycle pumping heat from the surroundings at 270K.
    I've drawn a diagram of the heat pump, taking heat Q2 from a bath of 270K up to an engine/refrigerator into which goes work W=50J, from which heat Q1 goes into hot bath of 280K. I am a bit confused about what to do next.
    Is it that the efficiency of a heat pump is = Q1/W = Q1/ (Q1-Q2) = ????


    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Apr 20, 2009 #2


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    It's actually referred to as "coefficient of performance" or COP, but yes that is the right idea.

    Compare the claimed COP with what you'd get for a Carnot Cycle heat pump operating at those temperatures, to determine whether this COP is possible.
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