The low temperature of a freezer cooling coil is $-8 ^\circ \textrm{C}$ and the discharge temperature is $33 ^\circ \textrm{C}$. What is the maximum theoretical coefficient of performance?

VIDEO TRANSCRIPT

This is Giancoli answers with Mr. Dychko. The ideal coefficient of performance for freezer is going to be the low temperature divided by the high temperature minus the low temperature. So we have negative eight degrees Celsius and then add 273 to convert it into Kelvin and divide that by the difference between the high temperature and the low temperature and I converted both of them into Kelvin in the bottom although that's not necessary because the plus 273 plus 273 works out to zero anyway. And just the size of a Celsius degree is the same as the size of a Kelvin. And so just taking three to three minus negative eight would work out the same. But anyway you can add the 273 to both of the temperature is if you like to. That also works and this all works out to 6.5 for the coefficient of performance.