Question

Suppose that the heat flow out of your 20°C home in the winter is 7

kW. If the temperature outside is -15° C, how much power P would an

ideal heat pump require to keep your inside temperature at 20° C?

Answer 1

$\frac{T_2}{T_1}=\frac{P_2}{P_1},$

$P_1=P_2\frac{T_1}{T_2}=8~kW.$