Question $6.$ The refrigeration cycle. $(20$ pt $)$

$(1)$ The throttling valve in the practical vapor$-$compression refrigeration cycle replaces the isentropic turbine. Determine the temperature change and enthalpy change of the working fluid entering and exiting the throttling valve. $($Increase or Decrease$)(5$ pt$)$

$(2)$ An ideal vapor$-$compression refrigeration cycle using refrigerant$-134$a as the working fluid is used to cool a brine solution to $-5C.$ This solution is pumped to various buildings for the purpose of air$-$conditioning. The refrigerant evaporates at $16\mathrm{.}00C$ with a total mass flow rate of $6\mathrm{.}000k\frac{g}{s}$ and condenses at $600$ kPa $.$ Determine the COP of the cycle and the total cooling load. $($Hint: $h1=hg$@$-16C=240\mathrm{.}9k\frac{J}{k}g,h2=268\mathrm{.}5402k\frac{J}{k}g,h3=hf$@$600$kPa$=81\mathrm{.}50k\frac{J}{k}g)(15$ pt$)$