Problem #$1(5$ pts$)$

A heat pump with R$-134$a enters the compressor as a saturated vapor at $-20C,$ and is compressed to $0\mathrm{.}8$ MPa at state $2.$ The fluid cools isobarically until it enters the throttling valve at state $3$ as a subcooled liquid at $0\mathrm{.}8$ MPa and $28C($you may estimate $h_3$ as $h_f$@$T).$ Plot the coefficient of performance Y $($Heat out per mass$/$work in per mass$)$ as the efficiency of the compressor $({}_c)$ is varied from $1$ to $0\mathrm{.}25.$ Plot at least $5$ data points. Remember that $h_1,h_{2s}($but not $h_2),$ and $h_3$ will be the same regardless of compressor efficiency.