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Homework Help: Thermodynamics energy efficiency

  1. Nov 20, 2007 #1
    1. The problem statement, all variables and given/known data
    Each second, a nuclear power plant generates 2000 MJ of thermal energy from nuclear reactions in the reactors core. This energy is used to boil water and produce high pressure steam at 573 Kelvins, the steam spins a turbine, which produces 700 MJ of electric power, then the steam is condensed and water is cooled to 303 kelvins before starting cycle again.
    a) maximum possible efficiency of plant?
    b) plant's actual efficiancy?

    2. Relevant equations
    emax= 1 - (Tc/Th)
    e= what you get/ what you pay

    3. The attempt at a solution

    a)emax= 1- (303/573) = 0.53
    b) e= work out/Qh = Qh-Qc/Qh = 1300/2000 = 0.65
    but this is larger then my max!!!!
  2. jcsd
  3. Nov 22, 2007 #2


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    Homework Helper

    Shouldn't the plant's efficiency be: 700/2000 ?

    The electric power produced is 700MJ. That's what you get. What you pay is 2000 MJ.
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