An electric water heater is delivering hot water at 50 C. The cold water enters the water heater at 10 C. The volume of the water heater is 160L and one fourth of the tank volume is cold water when the 5 kW electric heating element turns on. Once the heating element turns on, the internal energy of the water tank is a. Increasingb. Decreasingc. Constant

4r-134a enters the condenser of a residential heat pump at 800 kpa and 50°c at a rate of 0.022 kg/s and leaves at 750 kpa subcooled by 3°c. the refrigerant enters the compressor at 200 kpa superheated by 4°c determine (a) the isentropic efficiency of the compressor, (b) the rate of heat supplied to the heated room, and (c) the cop of the heat pump. also, determine (d) the cop and rate of heat supplied to the heated room if this heat pump operated on the ideal vapor-compression cycle between the pressure limits of 200 and 800 kpa. (0.757, 4.37 kw, 5.12, 6.18, 3.91 kw)