An R-12 vapour compression plant producing 10 tonnes of refrigeration operates with condensing and evaporating temperatures of 35ºC and -10ºC respectively. A suction line heat exchanger is used to sub-cool the saturated liquid leaving the condenser. Saturated vapour leaving the evaporator is superheated in the suction line heat exchanger to the extent that a discharge temperature of 60ºC is obtained after isentropic compression. Calculate
(i) The sub-cooling achieved in the heat exchanger
(ii) The refrigerant flow rate in kg/s
(iii) The cylinder dimensions of the two cylinder compressor, if the speed is 900 rpm, stroke-to-bore ratio is 1:1 and the volumetric efficiency is 80%.
(iv) The COP of the plant and
(v) The power required to drive the compressor in kW. Draw the cycles on P-h and T-s diagrams