Question

If a reversed Carnot cycle operates between the temperature limits of ${27}^{\circ }Cand-3^{\circ }C$, then the ratio of the COP of a refrigerator to that of a heat pump (COP of refrigerator/COP of heat pump) based on the cycle is (round off to 2 decimal places).

Answer 1

Given: $T_H={27}^{\circ }C=300K$

$T_L=-3^{\circ }C=270K$

$\frac{CO{P}_{ref}}{CO{P}_{HP}}=\frac{\frac{T_L}{T_H-T_L}}{\frac{T_H}{T_H-T_L}}=\frac{T_L}{T_H}=\frac{270}{300}=0.9$