provides the schematic of a heat pump using refrigerant 134a as the working fluid, together with steady-state data at key points. the mass flow rate of the refrigerant is 7 kg/min, and the power input to the compressor is 5.17 kw. (a) determine the coefficient of performance for the heat pump. (b) if the valve were replaced by a turbine, power could be produced, thereby reducing the power requirement of the heat pump system. would you recommend this power-saving measure? explain.