$2-15.$ A refrigeration process includes a compressor, as explained in detail in Chapter $5,$ because it is necessary to change the boiling point of the refrigerant, which is done by controlling the pressure. Chapter $3$ shows that the work required for compression is well approximated as equal to the change in enthalpy. Us

e Appendix F to find the change in specific enthalpy for each of the scenarios A through C$.$

A$.$ Freon $22$ enters the compressor as saturated vapor at $P=0\mathrm{.}5$ bar and exits the compressor at $P=2$ bar and $T=20C.$

B$.$ Freon $22$ enters the compressor as saturated vapor at $P=2$ bar and exists the compressor at $P=8$ bar and $T=60C.$

C$.$ Freon $22$ enters the compressor as saturated vapor at $P=5$ bar and exists the compressor at $P=20$ bar and $T=80C.$

D$.$ In these three compressors, the inlet and outlet pressures varied considerably, but the "compression ratio" $\frac{P_{\text{o}\text{u}\text{t}}}{P_{in}}$ was always $4.$ What do you notice about the changes in enthalpy for the three cases?