Thermodynamics Problem Solved!

1. Jun 11, 2007

neelakash

1. The problem statement, all variables and given/known data

Show that no refrigerator operating between two reservoirs at a given temperature can have higher co-efficient of performance than a Carnot refrigerator operating between the same two reservoirs.

2. Relevant equations
3. The attempt at a solution

Please check if I am correct

A perfect refrigerator is one in which no work is required to take heat from the low temperature region to the high temp. region.
This is not possible according to the second law of Thermodynamics
The coefficient of performance of a refrigerator
COP = QL / W
where W = work done
from the first law of thermodynamics we can write
COPideal = QL / ( QH - QL )
= TL / ( TH - TL )
= ( TL / TH) / [ 1 - ( TL / TH) ]
= ( TL / TH) / eideal
= analagous to an ideal Carnot refrigerator

Last edited: Jun 11, 2007
2. Jun 11, 2007