A commercial refrigerator with refrigerant-134a as the working fluid is used to keep the refrigerated space at -30°C by rejecting its waste heat to cooling water that enters the condenser at 18°C at a rate of 0.25 kg/s and leaves at 26°C. The refrigerant enters the condenser at 1.2 MPa and 65°C and leaves at 42°C. The inlet state of the compressor is 60 kPa and -34°C and the compressor is estimated to gain a net heat of 450 W from the surroundings. Determine
(a) the quality of the refrigerant at the evaporator inlet,
(b) the refrigeration load,
(c) the COP of the refrigerator, and
(d) the theoretical maximum refrigeration load for the same power input to the compressor.
