Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Thermodynamics exhaust power question

  1. Feb 10, 2009 #1
    1. The problem statement, all variables and given/known data
    An electric generating station is designed to have an electric output power 1.20 MW using a turbine with two-thirds the efficiency of a Carnot engine. The exhaust energy is transferred by heat into a cooling tower at 98°C.
    (a) Find the rate at which the station exhausts energy by heat, as a function of the fuel combustion temperature Th.
    ---MW

    If the firebox is modified to run hotter by using more advanced combustion technology, how does the amount of energy exhaust change?


    (b) Find the exhaust power for Th = 838°C.
    -----MW

    (c) Find the value of Th for which the exhaust power would be only half as large as in part (b).
    ----- K

    (d) Explain why no value for Th would give an exhaust power one quarter as large as in part (b).



    2. Relevant equations
    P=W/t
    e= 1-Tc/Th


    3. The attempt at a solution
    i have no idea where to start..all i know is that the outpot power = 1.40MW and that Tc is 110 C??..what do i do with this info..please help
     
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted