The particulars of a 20 TR R 22 food freezer are as follows:
Evaporator temperature – 30°C
Condenser temperature 40°C
Temperature of vapor leaving evaporator – 25°C
Subcooling of liquid with vapor in heat exchanger 5°C
Polytropic index of compressor 1.15
Superheating of suction vapor after passing through suctionvalve 15°C
Compressor clearance factor 0.05
Pressure drop in valves 0.2 bar suction
0.5 bar discharge
The compressor has 6 cylinders with bore equal to stroke. Itsrpm is 1500, and mechanical efficiency is 0.75. Determine
(i) Mass flow rate of refrigerant.
(ii) Piston displacement of compressor.
(iii) Cylinder diameter.
(iv) Motor horse power.
(v) Cooling requirement of compressor in kW.
