$(1)$ A portion of a two$-$stage compression refrigeration circuit operating

with $R-134$ a refrigerant is illustrated in the figure. Part of the

refrigerant at $1000$ kPa and $35C,$ state $1,$ is sent to tank A through

valve V$1.$ The other $($larger$)$ portion is sent to the evaporator

through valve V$2.$ In the evaporator, the refrigerant removes heat at

a rate of $100$ kW and its pressure is equal to $85\mathrm{.}1$ kPa $,$ leaving in

the saturated vapor state, $4.$ It is then compressed adiabatically

and reversibly to state $5,$ where it is introduced into tank A$.$

Saturated vapor, state $6,$ leaves tank A$.$ The pressure in tank A$,$

whose walls can be assumed to be adiabatic, is equal to: $350$ kPa $.$

Assume Steady State and neglect variations in kinetic and potential

energy in all processes. Determine:

$($a$)$ The refrigerant flow rate that circulates through the evaporator

$k\frac{g}{s}.$

$($b$)$ The liquid flow rate in state $1$ that is diverted to tank $A[k\frac{g}{s}].$

$($c$)$ The compression power of the vapor that leaves the evaporator to

state $5[kW].$

$($d$)$ Determine the rate of entropy generation in the evaporator $[$kW$/$K$]$

if the heat exchange is with an environment at $-30C.$

$($e$)$ Locate the different states on a diagram $($T versus s $).$