# Homework Help: Does Coefficient of Performance depend on refrigerant used?

1. Nov 24, 2013

### flatrate

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

Does Coefficient of Performance for refrigeration cycle depend on refrigerant used? In reference to vapor-compression cycle

2. Relevant equations

COP = $\frac{1}{\frac{T_{H}}{T_{L}}-1}$

3. The attempt at a solution

I am split in my answer to this question.

I understand that the COP isn't a material property of a refrigerant, but rather a measure of the performance of the refrigeration cycle. To increase coefficient of performance, we can minimize the gap between T_H (condenser) and T_L (evaporator). So in this case, it seems the only thing limiting the COP is the rate of heat removal (from load) by the evaporator and the rate of heat rejection from the system by the condenser.

However, would using different refrigerants allow for higher values of T_H and T_L to be removed or rejected?

2. Nov 24, 2013

### Staff: Mentor

I think the temperatures should be independent of the refrigerant - usually you want to cool something to a fixed temperature with a given temperature of the environment, and those do not depend on the refrigerant. Sure, you can increase the COP if you cool less, but then your fridge is pointless.

There could be more technical issues, no idea about that.