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Homework Help: Quick Carnot Engine Question

  1. Nov 22, 2008 #1
    1. The problem statement, all variables and given/known data

    A heat engine operates in a Carnot cycle between 80 degrees C and 350 degrees C. It absorbs 21,000 J of energy per cycle from the hot reservoir. a. THe duration of each cycle is 1s. What is the mechanical power output of the engine? b. How much energy does it expel in each cycle by heat?

    3. The attempt at a solution

    Part A

    Ideal Carnot Efficiency= 1- Tc/Th= .7714

    Power out=efficiency*power in

    Part B

    Wasted Energy=power in-power out

    Is that the correct strategy to solve this problem?
  2. jcsd
  3. Nov 22, 2008 #2
    It sounds to me like the question is asking (in part b) for the Heat Transfer out of the system in which case you mat want to consider writing out the Energy Balance for a closed system.

    For part (a) if by "power in" you mean the net rate of heat transfer into the system, then yes, that is correct.

    But, strictly speaking, there is no "power in".
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