Permenent ln2 loop

Conumdrum

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The Ln2 gets cooling by the expansion and release of stored cooling. Recycle? Then your talking some odd crazy thing. Design it using 100 watts per hour, sell it.

LOL, funny idea. Never gonna happen. You know how much it costs to make Ln2? To compress it to a liquid state?
 
You really don't realize just how much LN2 a continuous loop would go through, do you?

It would be constantly boiling off - easily using several liters per hour. LN2 is more just for screwing around and insane runs - the best you'll be able to do for constant use is a cascade setup (which can still get <-100C)
 

overshocked

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yes, but theoretically it is possible to use nitrogen as the refridgerant in a phase system.

The only problem is the system would be under a couple thousand psi. (not sure how much you guys know about phase)

A constant loop if used like thisw would only use about 2L everytime you charge it (6-12 months.


But you cant use it 24/7/. Its just to cold. The best you can get 24/7 is a single stage phase unit. This will pull about -50 for 24/7 use.
 
You could probably pull off a -120C cascade (though to get there, you'd probably need 3 stage - 2 stage are good for -90 or so) for 24/7, though it'd be loud, power hungry, and more maintenance intensive than most cooling systems out there.

As for LN2 in a phase change? It's actually not doable, at least not with a standard refrigeration cycle. Nitrogen's critical point is at -147C, which means that above that temperature, there is no longer a standard transition between liquid and gas (which is the whole point of a phase change setup). In order to work as a refrigerant in a phase change loop, the critical point of a substance must occur at higher than ambient temperature, otherwise you run into a lot of issues (the boiling point can be well below room temperature at standard atmospheric pressure though, so long as the critical point occurs at high enough temperatures - in fact to work well, the boiling point must be below ambient).
 

overshocked

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Wait a sec dude...

That is the point of a phase setup. You use propane (or another refridgerant) that has a boiling point of somewhere around -50. This gas is pressurized until its boiling point is above ambient so it truns into a liquid. The liquid goes into the evaporator and boils off sucking up tons of heat while it does this so you can reach negative temps on the cpu.

So the same principles would apply with LN2 as a refridgegerant. You would just need a extremely powerful compressor and some strong tubing.
 

richardscott

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overshocked the ln2 phase system wouldnt be anywhere near a couple of thousand psi as you would have to pre cool the n2 before it was compressed to reduce the operating temps but ofc this would add alot of complexity and cost, look up for a liquid helium generator and thats the same idea
 
was just thinking bout this after watching my friend go through his benching and reading bout the how the hadron collider has magnets cooled to near 0 kelvin so could a system like this work ? totally sealed in a vacuum ceramic lined casing feeding the cpu through a waterblock sort of most likely high strength of something piping using evoporated gass venting into the case and expelled now and then and i can get 200 liter ln2 a month for free
 

richardscott

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the lhc uses liquid helium which has to be run through stainless steel tubing as copper leaks they use helium in a superfluidic state so they have to boil off over 2/3 of the helium in order to get it to a super fluid. the lhc cooling uses alot of electricity, the old one was 36kw the new one is 50% more powerful and has the 1.9k stage to create the super fluid which is used for the cooling, if you can get free ln2 then just do benching like everyone else :p, your chip unless its a twker cpu then will cold bug before you get down to -196c, if you need it colder still you could pour the ln2 into the pot and use a vacuum pump to reduce the temps alot more
 


No, the same principles would not apply. The reason is because the critical temperature of nitrogen occurs at -147C, while the critical temperature for propane is 96.6C. Above the critical temperature, the substance will not condense into a liquid, regardless of the pressure (and therefore, the boiling point can never rise above that temperature). Instead, at those temperatures, above a certain pressure, it will become a supercritical fluid. This is not at all like a liquid, and does not allow for things such as evaporative cooling that a phase change setup relies on.

The requirements for a refrigerant, as I said before, are that it have a fairly low boiling point at ambient pressure (it should be well below the ambient temperature), and also that it have a critical temperature well above the ambient temperature. If both of these conditions are not met, it will not be an effective refrigerant. Nitrogen does not meet this second requirement, and as such, would not be a very effective refrigerant except as a cold stage in a cascade cooler with the hot side of the loop at a lower temperature than -147C. This is true regardless of the pressure that you try to use it at.
 

overshocked

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Thanks for clearing things up. :ange:
 

overshocked

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Thats a fantastic idea!!!

i never thought of using my vacuum pump to drop the pressure in the pot. How the hell would you go about that though?
 

overshocked

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May i ask where do you work and where do you live that you can get all that ln2 for free?

How much do the machines cost that extract the ln2 from the atmosphere?

How much do the LHE machines cost?

 

overshocked

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The phenom 2 x4's dont cold bug either. I was talking to k|ngp|in and he said that they will stop clocking at like -240.

Besides whats the point of getting lhe colder with lasers etc.

1.It stops clocking at -240c

2. LHE4 is already 5 degrees from absolute zero so there is really no point to get it to a superfluidic state. Not to mention like richard said you cant hold a superfluid in a copperpot because it will leak through. There for there is no point in doing that.

 

richardscott

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overshocked you would need two ln2 pots one open to the atmosphere which you need to top up, they get connected by short piece of pipe with a suitable valve, then the pot on the cpu will be closed with a pipe for the vacume pump, but tbh even a good vacume cleaner could reduce the temps, your after volume of gas removed not the pressure of the vacume, then when the cpu pot needs topping up you open the valve, and the vacume draws in the ln2 :D cant find a nitrogen phase diagram ;P was going to find the temp at say 0.5 bar :p but i fail
 

i work in an engineering company specialising in power transmission equipment in the design department and we use ln2 to cool the shafts to fit into gears and couplings ect,, we have an ln2 tank on premisses maintained by an other wing of our company, im friends with the MD he said i could take some now an then ,im from S.A.
 

overshocked

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eh..... doesnt matter, i used this calculater during lunch at school and even if you drop it to .5 bars the boiling point changes very little.


http://www.trimen.pl/witek/calculators/wrzenie.html

Boiling Point @ 1 atm: -320.5°F (-195.8°C, 77oK)
Freezing Point @ 1 atm: -346.0°F (-210.0°C, 63oK)


Now we just need dry nitrogen. (solid nitrogen) any one know where to buy it?
And the costs? Because it freezes at -210c.
 
this is from lhc ,
The collider tunnel contains two adjacent parallel beam pipes that intersect at four points, each containing a proton beam, which travel in opposite directions around the ring. Some 1,232 dipole magnets keep the beams on their circular path, while an additional 392 quadrupole magnets are used to keep the beams focused, in order to maximize the chances of interaction between the particles in the four intersection points, where the two beams will cross. In total, over 1,600 superconducting magnets are installed, with most weighing over 27 tonnes. Approximately 96 tonnes of liquid helium is needed to keep the magnets at their operating temperature of 1.9 K, making the LHC the largest cryogenic facility in the world at liquid helium temperature.

maybe do a bench in there hey