A heat pump using refrigerant$-134$a as a refrigerant operates its condenser at $900$ kPa and its evaporator at $2\mathrm{.}460$C$.$ It operates on the ideal vapor$-$compression refrigeration cycle, except for the compressor, which has an isentropic efficiency of $85$ percent. By what percentage do the compressor irreversibilities reduce the heat pump COP as compared to an ideal cycle? $($Round the final answer to three decimal places.$)$

$($Take the required values from saturated refrigerant$-134$a tables.$)$

The compressor irreversibilities reduce this heat pump$$s COP by $\%$ as compared to an ideal vapor$-$compression refrigeration cycle.