Refrigerant 22 in a refrigeration system enters one side of a counterflow heat exchanger at 12 bar, 28 °C. The refrigerant exits at 12 bar, 20 °C. A separate stream of R22 enters the other side of the heat exchanger as saturated vapor at 2 bar and exits as superheated vapor at 2 bar. The mass flow rates of the two streams are equal. Stray heat transfer from the heat exchanger to its surroundings and kinetic and potential energy effects are negligible.
Determine the entropy production in the heat exchanger, in kJ/K per kg of refrigerant flowing. What gives rise to the entropy production in this application?