What would it take to build a cryogenic cooler?

[Shingoshi]

How can a vortex tube work properly if the refrigerant is condensing inside the tube? Surely that would screw up the mechanics of the vortex, no?

But since I saw that you wrote here, I think it best to answer this question for everyone else as well.

I intend to build another four-socket system. However I'm going to test my four Tyan S2912 motherboards first in the phase-change chilled liquid-cooled arrangement. Actually, those four boards amount to 8 cpus. If I add the Tyan S4992 as previously intended, that will potentially give me 12 processors in the same system.

I'm really needing to think through my actions more carefully. But I think I want the four Rechi compressors in my first, followed by the Danfoss SC18CLX.2. The Rechi's have 31cc combined, while the Danfoss is only @16cc. From what I understand of how it was explained, having multiple compressors in parallel will raised the volume of refrigerant provided to the second-stage compressor. It would be as though the second-stage compressor were operating under higher atmosphere. See this thread to understand how this was explained to me.
http://www.spudfiles.com/forums/view...06.html#255906

Continuing, I think that I will have both stages work together as though they were only one single-stage. Let me see now if I can make sense of this to you. If you think of all the compressors working as the stages of a compressor in a turbine engine, you'll see how there is only one mixture passing through all stages. The only thing that's happening here is increasing the compression ratio of the turbine with each stage. But in my case, this might be like having a two-stage turbocharger with an intercooler between the stages.

I think I'm about to raise a subject here that I hadn't raised with you before. I have a fascination with vortex tubes. Look them up on Wikipedia. Now I'll continue with what I had already started writing below, before explaining myself here. :-)

However, if in testing I find that increasing the pressure of the inlet gas of a vortex tube (to @200psi) substantially increases the speed of rotation of the gas within it, I believe the result will be an increase in the performance/efficiency of the vortex tube. The object there being to cool my refrigerant between the first and second stages, without actually using a condenser. What I should see is an even greater transfer of heat from the core column of gas in the tube. Meaning it will be even cooler than otherwise at the same constant inlet temperature.

But then, if I compound this by also lowering the temperature of the inlet gas, the performance should be even more magnified. I may be able to get sub-zero inlet temperatures on the vortex, combined with the higher rotational velocities induced by the higher pressure. And since vortex tubes can be tuned to produce 90% of the inlet gas as cold outlet gas, I may be able to work with even colder gases than otherwise possible.

Testing for this would be as simple as running my compressed air through my liquid-cooled heat-exchanger.

Ok now I'll finish what I started to say above in my email to you.

Vortex tubes typically have an inlet temperature of 70F, with a working pressure of 100psi. The outlet temperature is @-30F, or lower. I've always wondered what happens if you change either of those.

1.) Increased pressure
I believe the vortex tube's function is dependent on the speed at which the gas within it rotates. Vortex tubes are what's known as "forced vortex" devices. Meaning the column of gas within it rotates as though it were a solid slug. The result is the outermost layer of gas draws heat away from the gas at the core. Because the outermost layer is expanding (excited molecules), while the innermost layer is contracting (less active molecules).

2.) Lowered temperature
It stands to reason that if the working inlet gas starts out being colder, the outlet gas should also be colder. How much, I don't know. But any improvement in dropping the temperature of the system is better than not doing so.

Now to answer your question about condensing the gas in the tube. My intent is to vertically orient the tube so that the cold outlet is pointing down. The hot end would be pointing up. With the inlet in the middle on the side.

As the gas begins to condense, it could easily exit the tube through the bottom. If in my case that gas is dumped into a second-stage compressor, you would have to be careful not to have condensation to the point of being a liquid. My primary intent here is to simply lower the temperature of the gas. I still want it to be a vapor when it enters the second-stage compressor.

I don't know what the lowest temperature is allowed to be for a compressor intake, provided the refrigerant isn't a liquid. But the cooler the inlet temperature, the less work will need to be done to condense the gas out of the second-stage compressor. I may be able to expand all the component gases in a single evaporator. And that raises another idea which I've yet to describe.

EDIT: Please see this link to visualize how the refrigerant may exist as both vapor and liquid inside the vortex tube. I'm thinking the central column may be a liquid, while the outer layer may be vapor. But again, I don't want a liquid going into the second compressor. I think what I want is a supercritical liquid, as explained here.
http://www.youtube.com/watch?v=4gVzL2pc0Gg

Shingoshi