As shown in the figure a refrigeration system operating on a

As shown in the figure, a refrigeration system operating on a vapour-compression cycle has mass flow rate of refrigerant 5 kg/s. The refrigerant R134a enters to the compressor as a saturated vapour at 140 kPa and exits at 800 kPa. The heat is delivered to the evaporator from a source at 260 K and the condenser rejects the heat to a sink at 300 K. Consider T_0 = 298 K and P_0= 100 kPa. Write all mass, energy, entropy and exergy balance equations for each process. Determine the quality of the refrigerant as it enters the evaporator. Determine the rate at which the shaft work input to the compressor. Determine energetic and exergetic COPs. Determine the heat input to the evaporator and the heat rejected from the condenser. Determine the rate of exergy destruction in the devices. For winter, it works in the heat pump mode. Calculate the energetic and exergetic COPs for HP.

Solution

The quality of refrigerant enter is saturated .

The rate at which shaft work input is 56 kw/rpm.

The value of both the COP is 6 and 4