$($b$)$ Calculate the power required by the two compressors in a R$134$a system which serves a

$(20)$

$80$ TR evaporator at $-40C$ and $100$ TR evaporator at $-10C.$ The system uses two stage compressions with inter$-$cooling and removal of flash gas. The condensing temperature is $30C$ and the intercooler temperature is $-10C.$ Draw the schematic diagram and P $-$h diagram of the system. Also calculate the COP of the system.