An electric water heater works by passing electricity through an electrical resistance placed inside the flow of liquid water as shown in the accompanying animation. The specific internal energy and entropy of water are correlated to its absolute temperature through u = 4.2T and s = 4.2lnT (T in K) respectively. Water enters the heater at 300 K with a flow rate of 5 kg/s. At the exit the temperature is 370 K. Assuming steady state operations, negligible changes in ke and pe, and negligible heat transfer, determine
(a) Electrical power consumption rate.
(b) The rate of entropy generation within the heater. What-if Scenario: What would the answers be if the exit temperature were reduced by 20oC?