Consider a Carnot heat-engine cycle executed in a closed system using 0.025 kg of steam as the working fluid. It is known that the maximum absolute temperature in the cycle is twice the minimum absolute temperature, and the net work output of the cycle is 60 kJ. If the steam changes from saturated vapor to saturated liquid during heat rejection, determine the temperature of the steam during the heat rejection process.

A refrigerator uses R-134a as the working fluid and operates on an ideal vapor compression cycle between 0.14 MPa and 0.8 MPa. If the mass flow rate of the refrigerant is 0.06 kg/s, determine (a) the rate of heat removal from the refrigerated space, (b) the power input to the compressor, (c) the heat rejection rate in the condenser, and (d) the COP.

A gas refrigeration system utilizing air as the working fluid possesses a pressure ratio of 3. The air is directed into the compressor at 5°C. The high- pressure air is then cooled down to 40°C by rejecting heat to the ambient environment. The refrigerant exits the turbine at -85°C and subsequently absorbs heat from the cooling area prior to its entry into the regenerator. The mass flow rate of air is 0.45 kg/s. Given that the isentropic efficiencies are 82 percent for the compressor and 87 percent for the turbine, and using constant specific heats at ambient temperature, find: (a) The effectiveness of the regenerator. (b) The rate at which heat is extracted from the cooling area. (c) The Coefficient of Performance (COP) of the cycle.

In a gas turbine, the temperature of the working fluid at inlet to the compressor is 289 K and outlet 438 K. At inlet to the turbine, the working fluid has a temperature of 1,064 K and exhausts from the turbine at a tempeature of 739 K. The specific heat capacity of the working fluid at constant pressure is 1.005 kJ/kg.K. Determine the efficiency of the plant