A cooling plant adopted a two-stage cascade refrigeration systemto meet the required cooling load. In both upper and lower cycles,the refrigerant leaves condenser as saturated liquid and enterscompressor as saturated vapor. The isentropic efficiency of theupper cycle compressor is 80 %, while the lower cycle compressor is70% efficient. The pressure limits of the upper and lower cyclesare 1 MPa and 0.2 MPa with refrigerant-134a, respectively. Heatrejection from the lower cycle to the upper cycle takes place in anadiabatic counterflow heat exchanger where the lower cycle entersabout at 0.5 MPa and the upper cycle enter about at 0.32MPa. If themass flow rate of the refrigerant in the upper cycle is 0.28 kg/s,determine
i. the mass flow rate of the refrigerant in the lower cycle
ii. the rate of heat removal from the refrigerated space and thepower input into the compressors
iii. the COP of the refrigerator
