What would it take to build a cryogenic cooler?

[Shingoshi]

Provided they could handle the pressures involved, how difficult would it be to modify them to function as condensers?

I would use two of these to dump this system's heat.

EDIT: Actually, I've figured this out on my own! None of the refrigerants will ever leave the internal environment of the case. Instead, I will isolate the high-pressure refrigerant stream by using another set of heat-exchangers as my internal condensers. The heat from them will then be disposed to boil a transfer fluid which will be evaporated and sent to the external radiators. There will be little pressure on these external units. They will only act as very large radiators for very large heatpipes. Situation solved.

Assembly Components (Listed in order of assembly):
2x 3" T-BOLT SS HOSE CLAMP 3.31"MIN/3.62"MAX DIA.
1x PVC-80 SOC WYE
2x 3" T-BOLT SS HOSE CLAMP 3.31"MIN/3.62"MAX DIA.
1x 3" MPT X 3" HB POLY 90 DEG HOSE BARB BANJO
1x 3" POLYPRO/EPDM THR X THR BLACK BULKHEAD FITTING
1x 3" MPT X 3" HB POLY STRAIGHT HOSE BARB
1x 3" T-BOLT SS HOSE CLAMP 3.31"MIN/3.62"MAX DIA.

These parts may be changed if better options are found.
EDIT: This is the next sub-system to be built. I have to build this before anything else to verify that I can indeed get rid of all this projected heat.

Shingoshi