Question $3$

$(7$ marks$)$

Refrigerant$-134$a enters the compressor of a refrigerator as superheated vapor at $0\mathrm{.}14$ MPa and $-10C$ at a rate of $0\mathrm{.}05k\frac{g}{s}$ and leaves at $0\mathrm{.}8$ MPa and $50C.$ The refrigerant is cooled in the condenser to $26C$ and $0\mathrm{.}72$ MPa and is throttled to $0\mathrm{.}15$ MPa $.$ Disregarding any heat transfer and pressure drops in the connecting lines between the components. Determine $(a)$ the rate of heat removal from the refrigerated space and the power input to the compressor, $($b$)$ the isentropic efficiency of the compressor, and $(c)$ the coefficient of performance of the refrigerator.

$\frac{\text{U}\text{s}\text{e}\text{f}\text{u}\text{l}\text{R}\text{e}\text{l}\text{a}\text{t}\text{i}\text{o}\text{n}\text{s}}{Q_L^{}-m(h_1-h_4)}$

$W_{in}^{}=m(h_2-h_1)$

${}_C$~$=\frac{h_{2s}-h_1}{h_2-h_1}$

$CO{P}_R-\frac{Q_L^{}}{W_{in}^{}}$