Based on compression cycle design, refrigeration cycle can simply divide into single stage, 2 stage and cascade compression cycle.
Single Stage Compressor System
Single stage compression cycle uses 1 set compressor, refrigerant gas is compressed once. The working flow is: Gas type refrigerant go through condenser and is cooled down to liquid form; then flow into evaporator, absorb heat and turn to gas type again; Move forward, the gas type refrigerant will suck by compressor, compressed to high temperature high pressure gas, and back to condenser again for cool down to liquid refrigerant.
Single Compression Cycle Compressor System Schematic Diagram
Single stage refrigeration compression system can reach -40C to -50C, which is very widely use.
2 Stage Compressor System
2 stage compression cycle divide the compress process of refrigerant gas into 2 stages, that is, low pressure gas which from evaporator will compress to middle pressure in low-stage compressor, after interstage cooling, then go to high-stage compressor.
The working flow of 2 stage compressor system is: Liquid form refrigerant goes out from condenser, will divide into 2 circuits. 1 is main circuit, also is 2 stage compression, the coolant go through intercooler and flow into evaporator, change to gas type and suck by compressor low pressure end, after compress turn to middle temperature middle pressure gas, after interstage cooling and suck by compressor high pressure end, flow forward to condenser and cool down to liquid form. Another circuit is go to intercooler through magnetic valve and expansion valve, absorb heat and turn to gas type, suck by compressor high-pressure end, and flow to condenser, cool down to liquid form.
2-Stage Compression Cycle Compressor System Schematic Diagram
2 stage refrigeration compression system is ideal for areas where need ultra-low temperature, typically it can reach -65C to -75C.
Cascade Compressor System
Cascade compression cycle combines high-temp and low-temp, 2 individual refrigeration systems. Which means there are 2 sets compressors, 2 kinds coolant, 2 refrigeration circuits. High-temp circuit mostly use R22 or 404a refrigerant, not direct cooling evaporator, but use for cooling low-temp circuit. Low-temp circuit mostly use R13 or R23 refrigerant which has a very low evaporating point, use for cooling evaporator. The 2 refrigeration system connect each other by a “Condense evaporator”, which is the condenser of high-temp system, also is the evaporator of high-temp system.
Cascade Refrigeration Compressor System Schematic Diagram
Cascade compressor system can reach very low temperature, -80C or deeper.