A heat pump is used to heat a house in the winter and cool it in the summer. The loads are 5000W in the winter with a house temperature of 20ºC and 4000W in the summer with a house temperature of 25ºC. Determine the minimum electric power in both cases if the year-round temperature three meters below the ground is 10ºC below the ambient temperature. State all assumptions made. (2 marks)