Why do we use Cascade Refrigeration Systems?

[Yousef Dajani]

I know that the Cascade Refrigeration Systems are more efficient than the normal Refrigeration Systems, but I still don't know why?

 

[Andy SV]

My thought is that you have an effective bump in efficiency at phase change from gas to liquid and the farther you get from the bump the less efficient... So two bumps is better

 

[Yousef Dajani]

My thought is that you have an effective bump in efficiency at phase change from gas to liquid and the farther you get from the bump the less efficient... So two bumps is better

I don't understand your opinion

 

[Andy SV]

Big sigh ... Yea I get that a lot

 

[Andy SV]

Ok so I will try to rephrase with more clarity.
Change from let's say liquid propane to a gas eats heat. But a change from gas to a thinner gas does to just not as much. Compression of that gas to a denser gas forces out the heat but not as much as compression of the propane to a liquid. So the temperature pressure range closer to where it changes phase is more efficient at moving heat. But that is not a wide range. So you get a different gas like carbon dioxide and cool it with the propane now it's a lot easier to concentrate condense into a liquid and you can stay in the temperature band that it is efficient in.
I hope that is better