A R12 refrigeration system has two evaporators at 4 TR and 2 TR respectively, kept at -4°C (Evaporator-2) and -20°C (Evaporator-1). The system uses one compressor and an individual expansion valve for each evaporator. The vapor from Evaporator-2 is throttled to the pressure of Evaporator-1. The two vapors are adiabatically mixed and compressed in the compressor. The condenser temperature is 40°C. Determine the enthalpies, temperatures, and entropies after throttling and adiabatic mixing. Find the mass flow rates and the work requirement of the compressor, condenser heat rejection, and the COP.