A heat pump heats a house in the winter and then reverses to cool it in the summer. The interior temperature should be 20 degrees celsius in the winter and 25 degrees celsius in the summer. Heat transfer through the walls and ceilings is estimated to be 2400 KJ per hour per degree temperature difference between the inside and outside.
a. If the winter outside temperature is 0 degrees celsius, what is the minimum power required for driving the heat pump?
b. For the same power as in part (a), what is the maximum outside summer temperature for which the house can be maintained at 25 degrees celsius?