Air $($Cp $=1\mathrm{.}005$ kJ$/$kg$.$K; R $=0\mathrm{.}287$ kJ$/$kg$.$k; $\backslash$gamma $=1\mathrm{.}4)$ enters the compressor in an ideal Brayton cycle at $1$ bar and $-2\backslash$deg C with a flow rate of $1\mathrm{.}6$ kg$/$s$.$ The compressor pressure ratio is $2\mathrm{.}8$ and the turbine inlet temperature is $28\backslash$deg C$.$ The coefficient of performance $($COP$)$ of the cycle is