Two stage cascade refrigeration systems are suitable for industrial
applications such as cryogenic separation in petrochemical
industries, liquefaction of petroleum vapors and natural gas, manufacturing
of dry ice, precipitation hardening of special alloy steel
and storage of food, blood etc. In these systems two single stage
units are thermally coupled through the cascade heat exchanger.
The low temperature circuit of a transcritical cascade refrigerant
system can normally be charged with N2O, propane (R290), propylene
(R1270), and ethane (R170) for cooling whereas, carbon
dioxide (R744) is used in the high temperature circuit for heating
applications.