An R 22 refrigeration cycle (shown on the following page) is used to provide 35 kW of cooling at -20 °C. R 22 leaves the water-cooled condenser 3 °C subcooled. The condensing temperature is 25 °C and the temperature in the flash tank is 0 °C . A portion of the flow from the condenser is cooled in the flash tank to 10 °C before going through the expansion valve to the evaporator. The vapour leaves the evaporator 5 °C superheated.
Both compressors have an adiabatic efficiency of 88 % and a volumetric efficiency of 73%.
a) Show the cycle on a large p-h diagram, writing in all enthalpy values as they are read off the tables or calculated.
b) Calculate the power requirement of each compressor and subsequently the coefficient of performance of the cycle.
c) Calculate the displacement rate in liters per second of only the low stage compressor.
The P-H Diagram, Power Requirement, Displacement Rate of a R 22 refrigeration cycle is calculated.