1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
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: Proving efficiency

  1. Feb 29, 2004 #1
    I'm having trouble with proving the following question. Can someone please help, please.

    (1) Prove that if you had a heat engine whose efficiency was better than the ideal value (4.5) you could hook it up to an ordinary Carnot refrigerator to make a refrigeratior that requires no work input.

    I know that efficency = 1-Qc/Qh and COP=1/(Qh/Qc - 1)but how do i prove the above question?
  2. jcsd
  3. Mar 1, 2004 #2


    User Avatar
    Homework Helper

    Either I'm really ignorant of this thermo stuff, or you've gotten the wrong number for efficiency. I think it should always be less than unity.

    My first step would be to draw a diagram. Make sure to include the hot and cold reservoirs and the directions of energy/heat flow. That should give a good picture of what's going on.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook