A vapor compression refrigeration system operates with R$134$a with a flash chamber and a single compressor. The evaporator is at $300$ kPa and the condenser is at $1200$ kPa $.$ The enthalpy of saturated liquid and saturated vapor at the evaporator pressure are $\backslash (50\backslash$mathrm$\{$~kJ$\}/\backslash$mathrm$\{$kg$\}\backslash )$ and $\backslash (265\backslash$mathrm$\{$~kJ$\}/\backslash$mathrm$\{$kg$\}\backslash ),$ respectively. The refrigerant enters the condenser with an enthalpy of $\backslash (281\backslash$mathrm$\{$~kJ$\}/\backslash$mathrm$\{$kg$\}\backslash )$ and it leaves the condenser as subcooled liquid with an enthalpy is $\backslash (100\backslash$mathrm$\{$~kJ$\}/\backslash$mathrm$\{$kg$\}\backslash ).$ The refrigerant leaving the condenser is throttled to a flash chamber which is also at evaporator pressure. In the flash chamber the vapor is separated and only the liquid fraction enters the evaporator. The refrigerant leaves the evaporator as saturated vapor and is mixed with the vapor from the flash chamber in a mixing chamber and sent to the compressor. Determine the COP of the refrigeration system if the mass flow rate through condenser is $0\mathrm{.}45\backslash (\backslash$mathrm$\{$kg$\}/\backslash$mathrm$\{$s$\}\backslash ).$

Answer:

The correct answer is: $10\mathrm{.}31$