Cooling Massive Heat Loads

[danwill51]

US Iceman,

My experience with running single stage chambers down to -40 hasn't been too good. I can get them down there but they have almost no capacity below -20C or so. I have a 2HP system that can only handle about a 200w load below -35C. I think with the high heat load I might need to go cascade. Since I am not a cascade designer (or anything like that) I will probably have to purchase one. Cascade Tech sells them but they are not cheap dose anyone know a company that sells premade cascade refrigeration units?

[US Iceman]

This is not a typical application. It is not the same as a walk-freezer. Heat load has nothing to do with needing a cascade system.

The use of cascade system might be required when the temperatures needed are lower than you can reasonably attain with either single stage or two stage systems. At -40°F (or -40°C) the system has to be designed to provide the required capacity at that temperature. You certainly do not need a cascade system for this temperature IMO.

If the system you mentioned does not reach the desired temperature the system is either not designed properly or is operating outside of the design point where it was designed to operate.

Most of the issues you mention are ones normally encountered in this type of work. They are all solvable, if approached right.