An air-source heat pump warms a house to on a day when the outside air is at

PHYSICS · Multi-part · Fermi University Physics · Thermal, Statistical & Complex Systems · The laws of thermodynamics · The laws of thermodynamics

Thermal Physics, Ch Heat engines, refrigerators and the Carnot cycle

Problem

An air-source heat pump warms a house to

294\,\mathrm{K}

on a day when the outside air is at

278\,\mathrm{K}

. Treat the house interior and the outside air as reservoirs at those temperatures. The pump must deliver heat to the house at a rate of

6.0\,\mathrm{kW}

. ((a)) What is the Carnot (largest possible) coefficient of performance

\mathrm{COP}_{\rm hp} = Q_h/W

for heating? ((b)) The installed unit achieves

\mathrm{COP}_{\rm hp} = 3.8

. What electrical power does it draw? ((c)) At what rate is heat drawn from the outside air?