A simple vapor compression refrigeration cycle using R$-134$a as the working fluid operates at $4C$ across the evaporator and $1$ MPa at the condenser is shown in FIGURE Q$2.$ The isentropic efficiency of the compressor is $80\%.$ The cooling load is $2\mathrm{.}5$ kW $.$

a$.$ Sketch this refrigeration cycle processes on a $T-s$ diagram indicating all the temperatures and pressures.

$[5$ marks$]$

b$.$ Determine the required mass flow rate of $R-134a.$

$[8$ marks$]$

c$.$ Calculate the rate of heat rejected from the condenser and the coefficient of performance, COPR of the cycle.

$[6$ marks$]$

d$.$ If the cycle is replaced by a reversed Carnot cycle, evaluate the required compressor work and the resulting $COP{R}_R.$

$[6$ marks$]$