An air conditioner using refrigerant-134a as the working fluid and operating on the ideal vapor-compression refrigeration cycle is to maintain a space at 22°C while operating its condenser at 1000 kPa. Determine the COP of the system when a temperature difference of 2°C is allowed for the transfer of heat in the evaporator. (Take the required values from saturated refrigerant-134a tables.) The COP of the system is

Consider a two-stage cascade refrigeration system operating between the pressure limits of 1.4 MPa and 280 kPa using refrigerant-134a as the working fluid. The heat rejection from the lower cycle to the upper cycle occurs in an adiabatic counterflow heat exchanger where the pressures in the upper and lower cycles are 0.5 MPa and 600 kPa, respectively. In both cycles, the refrigerant exits the condenser as a saturated liquid and enters the compressor as a saturated vapor. The isentropic efficiency of the compressors is 85 percent. Given the mass flow rate of the refrigerant through the lower cycle is 0.18 kg/s, calculate: (a) The mass flow rate of the refrigerant through the upper cycle. (b) The rate of heat extraction from the cooling area. (c) The Coefficient of Performance (COP) of this refrigeration system.

An air conditioner using refrigerant-134a as the working fluid and operating on the ideal vapor-compression refrigeration cycle is to maintain a space at 36.00°C while operating its condenser at 1600 kPa. Determine the COP of the system when a temperature difference of 4.000°C is allowed for the transfer of heat in the evaporator. (Take the required values from saturated refrigerant-134a tables.) (Round the final answer to three decimal places.) The COP of the system is

A two-evaporatoor compression refrigeration system like that in the Figure below uses refrigerant-134a as the working fluid. The system operates evaporator 1 at 30 psia, evaporator 2 at 10 psia, and the condeser at 180 psia. The cooling load for evaporator 1 is 9000 Btu/h and that for evaporator 2 is 24,000 Btu/h. Determine the power required to operate the compressor and the COP of this system. The regrigerant is saturated liquid at the exit of the condenser and saturated vapor at the exit of each evaporator, and the compressor is isentropic.