$10\mathrm{.}38$ A process requires a heat transfer rate of $5{10}^{4}Bt\frac{u}{m}in$ af $170F.$ It is proposed that a Refrigerant $134$a vaporcompression heat pump be used to develop the process heat using a waste water stream at $125F$ as the lower$-$temperature source. Specify appropriate evaporator and condenser pressures of a cycle for this purpose. Let the refrigerant be saturated vapor at the evaporator exit and saturated liquid at the condenser exit. Calculate

$($a$)$ the mass flow rate of refrigerant, in $l\frac{b}{h}.$

$($b$)$ the compressor power, in horsepower.

$($d$)$ the coefficient of performance.