Consider a two-stage R-12 refrigeration system operating between 0.15 MPa and 1 MPa. The refrigerant leaves the condenser as saturated liquid and is throttled to a flash chamber operating at 0.4 MPa. The vapor from the flash chamber is mixed with the refrigerant leaving the low-pressure compressor and the mixture is compressed by the high-pressure compressor to the condenser pressure. The liquid in the flash chamber is throttled to the evaporator pressure where the cooling load is handled through evaporation. Assuming the refrigerant leaves the evaporator as saturated vapor and both compressors are isentropic, determine
(a) The fraction of refrigerant that evaporates in the flash chamber,
(b) The cooling load and (c) the COP.