1. an ideal refrigerator (no irreversibility) uses refrigerant-134a as the working fluid and operates on the vapor- compression refrigeration cycle. the evaporator and condenser pressures are 200 kpa and 1400 kpa, respectively. the refrigerant enters the compressor at a rate of 0.025 kg/s superheated by 10.09°c (with respect to the saturation temperature) and leaves the condenser subcooled by 4.40°c (with respect to the saturation temperature). there are no pressure drops in the refrigerant as it flows in the condenser or evaporator.
answer the following:
a. sketch the cycle on a t-s diagram. show the isobars with their values and the temperatures at the inlet of the compressor, exit of the condenser and exit from the expansion valve.
b. compute the rate of heat rate removed by the evaporator, in kj/s, with three decimal places.
c. determine the power supplied to the compressor, in kw, with three decimal places
d. determine. cop of the refrigerator.
2. answer all the parts for problem 1 but this time the compressor has an isentropic efficiency equal to 0.88 and the refrigerator operates between the same pressure limits and the conditions for the inlet to the compressor and exit from the condenser and refrigerant flow rate are the same as for problem 1. there are no pressure drops in the condenser or evaporator.