Refrigerant R-134a enters the evaporator coils placed at the back of the freezer section of a household refrigerator at 120 kPa with a quality of 20 % and leaves at 120 kPa and -20°C. If the compressor consumes 450 W of power and the COP is 1.2, determine
a) the mass flow rate of the refrigerant and
b) the rate of heat rejected to the kitchen air.