Air enters the evaporator section of an air-conditioner at 100 kPa, 27oC with a volumetric flow rate of 6 m3 /min. R-134a enters the evaporator at 120 kPa with a quality of 0.3 and rate of 2 kg/min and it leaves as a saturated vapor at the same pressure.
Determine (a) the exit temperature of the air (oC) and (b) the rate of entropy production (kW/K) for the process in two ways:
1. Assume the outer surface of the evaporator is insulated. (2) Assume the outer surface is not insulated and heat is transferred from the surrounding medium which is at 32oC to the evaporator at a rate of 30 kJ/min.