An electric water heater having 0.2 m3 capacity employs an electric heater to warm the water from 22°C to 55°C. The outer surface of the electric heater element remains at an average temperature of 80°C. The water tank is well insulated. Assuming steady state conditions at the initial and final temperatures, that the change between the initial and final states of the electric heater and the tank wall is negligible, and that the water at the constant pressure of 1 bar is incompressible, determine the amount of entropy produced, in kJ/°C, for
a. The water as the system
b. The overall water heater including the heater.