Evaluate a proposal to provide $1\mathrm{.}35$ kW of heat to a drying

compartment to be maintained at $45C$ by means of a heat pump using

Freon$-12$ as the working fluid that will extract heat from the

surroundings at $20C.$ The working fluid inside the heat pump will

condense at $55C$ and will evaporate at $5C.$ The working fluid will

enter the expansion valve at $50C.$ For a $90\%$ efficient compressor,

determine $($a$)$ the coefficient of performance $($b$)$ the rate at which the

working fluid will have to circulate within the heat pump and $($c$)$ the

cost of providing the heat if electricity costs $10$ cents $\frac{?}{kWhr}.$