2.3 Determine the energy (in megajoules) required to use an electric heater at full rated capacity of 2 kW, and 3 water pumps, rated at 0.75 kW, for 45 minutes simultaneously.

In the winter, in order to keep the classroom steadily at 68 f before 10 pm, heating with an average rate of 42,000 btu/hr is provided. assume the outdoor temperature maintains at 32°f, determine the electrical power (kw) required to (a) operate a reversible heat pump (b) operate a real heat pump with a cop (7) of 4.5 and (c) operate an electrical-resistance heater.