View Full Version : an interesting idea
05-13-02, 11:24 PM
i know that expanding gasses remove alot of heat and i was thinking of a reasonable enviromentaly sound coolant that is widly available... HELIUM it comes in a liquid form of you have access to a walmart. it is phesable to either mod an existing compressor with helium or perhaps find one though its not common... btw does anyone know the boiling point? the idea came to me when at the local party suplies place and i notice that when they were inflating alot of baloons the tanks begin to gather condensation... anyways just an idea i had thought id throw it out.
Actually you can't use helium that way. The tanks of helium that you get are not liquid helium, rather high pressure helium gas. To get and store liquid helium is a VERY expensive process. I know this because we use liquid helium for superconducting magnets at our lab. The boiling point of helium is somewhere around 5 degrees Kelvin.
Another problem is after -50 deg. celsius, you hit a point where you will start damaging your cpu. Basically, the silicon traces inside the cpu packaging shrink more than the packaging, so they will start tearing themselves apart. This is why all these cases where people cool with liquid NITROGEN result in a short oc before the cpu dies. At least liquid nitrogen is cheap (cheaper than milk), but trying to recompress it will get expensive.
To give you an idea of how we use things, we have the superconducting coils sitting in a flow of liquid helium which is supplied by the compressors. Around the whole assembly (except the compressors) is a bath of liquid nitrogen which is just exhausted since its cheaper to let it evaporate away than to try and recompress it.
To make a long story short (too late :D ) it may be fun to try a project with liquid helium to see what kinda oc you can get for a few minutes, its not a viable long term solution.
05-13-02, 11:37 PM
Interesting, but Im not sure it would work. It requires quite abit of energy to liquify helium, I think a standard refrigerent would do fine.
05-13-02, 11:37 PM
The boiling point of Helium is -268.93C. OR 4.07K (if my conversion is right) But, that's at 1atm. When the pressure goes up, then the boiling point goes down, which is how they are able to store it.
edit: I see I was beaten to it!
05-13-02, 11:51 PM
well seing as i expected that the boiling point of helium would be higher than freon cus im to lazy to research the boiling points of such things myself.... yea id imaging that it would just be way to much effort to maintain... perhaps i might atempt to just cycle high preasure gas through a wb and recirculate it might be a viable option but perhaps inefficant and obviously diffacult to do.
05-13-02, 11:53 PM
I was thinking of doing that, but I posted here and found out it was a bad idea. (turning my maze2 into an evaporator)
When the compressor shuts off for a little while to rest, there goes your CPU!!:eek: :eek:
05-13-02, 11:57 PM
Read the ENTIRE Project X thread... You will find a lot of answers to questions. Plus the evaporator needs to be in direct proportions to the compressor and condensor...
05-14-02, 12:02 AM
not using liquid to gas setup just high preasure gas circulating
05-14-02, 01:14 AM
THat will only work to kill you CPU in a matter of seconds. In order for the heat to be moved, the gas needs to start as a liquid, get boiled into a gas, and then be compressed back into a liquid to keep the cooling cycle continuous. If the gas is under a constant pressure, it won't be able to pick up any heat I don't think.
05-14-02, 01:21 AM
There was a thread at [H] where they put a 1.4 t-bird into a LN2 bath for a like 24 hours and when they took it out it was fine. I would see no reason why running it with juice going through it would be much different. I ran a cel-t at -70 deg. C with dry ice for 14 hours once here at OC.com. I documented every thing right here through the whole process.
05-14-02, 02:08 AM
Practical is the term here. How much LN2 did they use? Did they just pour it in a resevoir with the mobo and seal it? If so, then it isn't using the full heat transferring ability of LN2. It would only allow for so much heat to be moved. 14 and 24 hours are not tests. Would you trust a salesman who said he drove your car for 14 hours and nothing exploded so it's fine? I hope not. If you want to run a series of tests, build a system where the LN2 gets recycled, like a phase change system. We'll start out at 1000 hours for simple testing. Build the CPU usage up to 100% and let the LN2 flow. Initiate a power down/startup cycle every 30 minutes. Then we'll take a look at the data of the 2000 cycles within 1000 hours. If it passes then we can start looking at bench marks. Of course I would like to see anyone use the $30,000 worth of equipment needed to supply the LN2 in a phase change.
05-14-02, 07:34 PM
creeping death what im thinking of doing is a closed cycle gas cooling system basicly what i would like to do is to take a fin style heatsink and incase it with a hose at both ends one inlet for the gas and the outlet. it would then cycle through a radiator beacouse i see no other pratical way to get the heat out of the gas quickly... anyways where it will empty into a holding tank before it is recirculated through the system.
05-14-02, 07:48 PM
Ok, but there will be no difference between doing what you are talking about and having a normal fan on a heatsink. Air is air.
05-14-02, 08:59 PM
Helium doesn't have much better of a specific heat than plan air does.. In my field I've seen lots of company's/people try to come up with some kind of CO2.. Helium.. and etc gas cooling methods and recycle the gas.. with out compressors to pump the gas back into a liquid state Its pointless
05-14-02, 09:14 PM
i find this entire board fascinating... especially when someone wants to try something new. So thanks for the info guys.
Second, alternative cooling is a bitch. It centers around 3 things. Air, water and phase change. We have all seen/heard many variations of the them... but its one of those things (bongs are kinda unique).
Anyway, ive only read of a few techniques that dont involve those 3 and they are insanely expensive, meant for advanced research labs. I think "pulse" cooling was the name of one. It could get an object down to 5 kelvin. But thats not real usefull for us :(
Anyway, has anyone heard of cooling that doesnt rely on the 3 methods i have mentioned?
05-14-02, 09:25 PM
prehaps but if you have the gas compressed not quite to a liquid state fire it down a narrow tube and let it into a large chamber with a wide outport you can possibly get a better cooling effect.
05-14-02, 10:34 PM
I see what you are saying... You are saying that if you send it down a tube as compressed air, or air under great pressure, but not so much that it transforms to liquid, and then sorta expands into a different pressure zone hopefully drawing some heat into the equation? Ok here are a few problems...
1. You are still going to need a compressor. However, the gas under different pressures is just going to create faster moving air in certain areas. Imagina a can of air, like the computer dusting stuff. It's compressed, into a liquid as a matter of fact. As you press the trigger, the air decompresses and flys out at a rapid speed. But the only reason why this happens is because the pressure is so much less on the outside. If you are going to have a closed system, you might be able to get 2 sides with different air pressures, but they will not be able to mix. And if they do they will stabilize. Imagine you have 2 different compressed areas C1 and C2. And then you have the compressor- C. You might be able to get a setup like this- C1-C-C2-C and repeat. Now since the all the air pressure in the C1 compartment is the same, no air will be moving faster there. And Since the air pressure in the C2 compartment is the same, no faster air there either. A great amount of energy is required to change the state of matter. When that transformation takes place is when you get the desired affects.
Geez.. I can't remember my other points now lol. I'll write later if I remember them.
05-15-02, 08:31 AM
ok well im just throwing out ideas... i had the idea of the liquid helium but now i realise that isnt doable then i though that a compressed gas system might work but i see the flaws in the system... anyways thanks for the help and as i said just throwing out ideas.
05-15-02, 10:28 AM
Don't worry. Every idea that anyone throws out is met with constructive criticism. It's good to see that people are actaully thinking and not just running into the forums screaming TELL ME HOW TO OVERCLOCK MY COMPUTER.
05-15-02, 10:58 AM
heh, if only they were that literate half the time :D
05-15-02, 06:18 PM
Liquid helium would be cool if silicon could handle it, but at a coupel degrees above absolute zero, the CPU would die very quickly, even if the CPU were slowly lowered to that temp. Hmm, a 4GHz Athlon?
05-15-02, 11:32 PM
i think the silicon could take it if it were lowered at a constant rate and capable of maintaing the temprature with a minimul fluxtuation which is totaly improbable you know you will have a fluctuation of 4C or so which is enogh to expand and contract just enough to crack said core. if they only designed cpus for extrem cooling measures by giving the chip room to contract without crushing the links.
05-16-02, 02:23 AM
The silicon will retract from the core anyway with prolonged exposure to extreme cold. It is a dead CPU definitely at LiHe temps.
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