Coefficient of performance for a refrigerator

[rmjmu507]

Homework Statement

The COP for heat pumps and refrigerators achieved in the industry is almost 50% of the Carnot limit. Make estimates for the following case:

For refrigerator to achieve -10°C in the freezer area with an external temperature of 25°C

Homework Equations

COP for refrigerator = T(low) / [T(high)-T(low)]

The Attempt at a Solution

Using this equation, I find that the COP is 7.5, but this seems high. Where have I made a mistake?

 

[CWatters]

You calculated the Carnot COP but the problem statement says..

The COP for heat pumps and refrigerators achieved in the industry is almost 50% of the Carnot limit