Cascade system

In a cascade system a series of refrigerants with progressively lower boiling points are used in a series of single stage units. The condenser of lower stage system is coupled to the evaporator of the next higher stage system. The cascade system may be of 2-stage, 3-stage and so on. The two systems are connected with a cascade condenser or heat exchanger which acts as an evaporator for low temperature cascade and as a condenser for high temperature cascade. An example of refrigerant combination is the use of carbon dioxide in low temperature cascade and ammonia in high temperature cascade.

Applications of cascade system:

• Liquefaction of petroleum vapours,
• Liquefaction of industrial gases,
• Manufacturing of dry ice,
• Deep freezing, etc.