Refrigerant 134a is the working fluid in a vapor-compression heat pump system with a heating capacity of 70,000 Btu/h. The condenser operates at 180 lbf/in2, and the evaporator temperature is 20˚F. The refrigerant is a saturated vapor at the evaporator exit and exits the condenser at 120˚F. Pressure drops in the flows through the evaporator and compressor are negligible. The compression process is adiabatic, and the temperature at the compressor exit is 200˚F. Determine
a) The mass flow rate of refrigerant, in lb/min
b) The compressor power output, in horsepower.
c) The isentropic compressor efficiency.
d) The coefficient of performance.