A refrigerator (see Figure below) is used to keep a cold storage space (cold source) at -20 C (assume the evaporator saturation temperature is lower by 5 C). To do so, it needs to remove 3.5 kW from the storage space. The temperature outside the system (hot source) is 25 C (assume the condenser saturation temperature is higher by 10 C). The cycle uses refrigerant R22. With this refrigerant and under the described operating conditions, the actual coefficient of performance (COP) of the cycle is 2. (Hint: Assume the outlet flow from the condenser is saturated liquid and the outlet flow from the evaporator is saturated vapor. Deal with condenser and evaporator as stream flow with heat transfer.) a) What is the operating pressure at the low-pressure side of the cycle (evaporator)? b) What is the operating pressure at the high-pressure side of the cycle (condenser pressure)? c) What is the quality of the process stream at the INLET to the evaporator in the cycle? d) What is the mass flow rate of R22 needed to achieve the desired amount of cooling? e) Calculate the work required by the compressor in units of kW. f) What is the isentropic efficiency of the compressor? g) What is the rate of entropy generation for each component, with proper comments and recommendations? Wnet 1: 2= vapor Compressor vapor Vapor-compression cycle Hot reservoir Heat sink Qhot Condenser Evaporator Qcold Cold reservoir Heat source liquid liquid + vapor 3 4 Expansion valve