Refrigerant 134a is the working fluid in a vapor-compression heat pump system with a heating capacity of 55,000 btu/h. the condenser operates at 300 lbf/in? , and the evaporator temperature is -20°f. the refrigerant is a saturated vapor at the evaporator exit and a liquid at 120°f at the condenser exit. pressure drops in the flows through the evaporator and condenser are negligible. the compression process is adiabatic, and the temperature at the compressor exit is 200°f. determine the mass flow of the refrigerant in ibm/min. the tolerance is ±5%.