A heat pump is to be used to heat a house in winter and then reversed to cool the house in summer. The interior temperature is to be maintained at 20°C. Heat transfer through the walls and roof is estimated to be 0.525 kJ/s per degree temperature difference between the inside and outside.
a) If the outside temperature in winter is 5°C, what is the minimum power required to drive ‘the heat pump
b) If the power output is the same as in part (a), what is the maximum outer temperature for which the inside can be maintained at 20°C?