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Homework Help: 2nd law of thermodynamics heat pump problem

  1. Mar 10, 2016 #1
    1. The problem statement, all variables and given/known data
    Here is the problem:

    An inventor claims to have developed a heat pump that provides a 180 kW heating effect for a
    293 K household while only consuming 70 kW of power and using a heat source at 273 K. Can this
    claim be possible?

    2. Relevant equations
    COP of heat pump = Qh/W
    COP of heat pump (carnot max) = Th/(Th-Tl)
    n (thermal efficiency) = W/Qh = 1-(Ql/Qh)
    n(max carnot) = 1- (Tl/Th)

    3. The attempt at a solution
    The answer to this problem is that the claim is valid because the COP of the heat pump is less than the COP max, I just want to know can I use thermal efficiency instead of COP to see if this claim is valid?
  2. jcsd
  3. Mar 11, 2016 #2


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    Science Advisor
    Homework Helper
    2017 Award

    Well, what is the definition of the COP ?
    Cengel CH 6 has plenty examples (check 6-78)
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