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.

Awall of 0.5m thickness is to be constructed from a material which has average thermal conductivity of 1.4 w/mk. the wall is to be insulated with a material having an average thermal conductivity of 0.35 w/mk so that heat loss per square meter shall not exceed 1450 w. assume inner wall surface temperature of 1200°c and outer surface temperature of the insulation to be 15°c. calculate the thickness of insulation required.