7. A heat pump with a coefficient of performance of 3.8 provides energy at an average rate

of 75,000 kJ/h to maintain a building at 21°C on a day when the outside temperature is

0°C. If electricity costs 11.5 cents per kWh:

a. Determine the actual operating cost and the minimum theoretical operating cost

in $/day.

b. Compare the results of part a with the cost of electrical resistance heating.