A 4-m x 5-m x 7-m well-sealed room is to be heated by 1500 kg of liquid water contained in a tank that is placed in the room. The room is losing heat to the outside air at 5°C at an average rate of 10,000 kJ/h. The room is initially at 20°C and 100 kPa and is maintained at a temperature of 20°C at all times. If the hot water is to meet the heating requirements of this room for a 24-h period, determine
(a) The minimum temperature of the water when it is first brought into the room and
(b) The entropy generated during a 24-h period. Assume constant specific heats for both air and water at room temperature.