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Olen
07-05-2007, 04:53 PM
I was thinking again of all things cool and I was wandering why noone has ever, to my knowledge, tried this idea.

First a little background: phase change cooling, this basically means that a liquid turns into a gas. This takes heat which does not contribute to raising the temperature, for example it takes about six times more energy to turn a pan of water at boiling point into steam at the same temperature as it did to heat the pan from room temperature to boiling point. Pritty effective eh?

Now when you compress a gas its boiling point increses (this is how a pressure cooker can boil things at 120*C). So if you get the right gas you compress it and it turns to liquid giving out lots of heat which is dumped in a radiator, if you then decompress the liquid it boils taking away lots of heat. This is how a fridge works. And also how vapochill systems work.

But I have an idea which is simpler and probably more effective. What if, after the gas has been compressed it were decompressed far more voilently, say by squirting out of a jet into lower pressure. Lots of cooling. What if that jet were directed at a heatsink... It would be like cutting out the middle man and putting the component inside the vapochill's tubes.

Here's a quick sketch up of the idea: note I have only bothered showing one narrow pipe as I'm lazy, there would be two or three - the one shown is for the GPU, the CPU would have one as might other 'hotspots'.
http://i69.photobucket.com/albums/i58/Seidr/server/basicidea.jpg

The whole system is sealed with only the coolent (I'm thinking about R31 (if I can get it) just now) inside, this is drawn though the large pipe at the top of the computer case into the little box next to it which houses a compressor (taken from a large freezer) this turns the gas to liquid then cools that to ambient temperatures. The high pressure liquid is then taken back in the thin pipes and fired though thin jets at hot components - graphics card, cpu, north bridge - and random spray and general coldness should do the rest. Obvoisly drives etc would be housed outside and cables would be sealed in. The expansion slots in the case would also be sealed as would everything to stop coolent escaping.

The only possible issue I can forsee is finding a large enough compressor willing to work against that sort of pressure gradient (I'm looking at two or three bar (c. 40psi) difference from one side to the other). Also finding a suitable coolent as pressures over 5bar (75psi) above ambient worry me too much as if anything burst it would do you real damage.

Can anyone think of any improvements? Is this just to dangerous to be sensible trying? Its an unusual ideas but it seems never to have been done and might work. Does anyone know what components make of high pressure?

rendermandan
07-05-2007, 05:17 PM
wow, so let me understand this, are you going to pressurize the computer case with freon?

Spawn-Inc
07-06-2007, 02:43 AM
wouldn't work very good. be a lot cheaper, safer, safer to the envrionment, and over all easier to just use a standard phasechange setup. or have a/c installed in your pc. that would be very hard, next to impossible to get a proper seal. and to my knowledge there is no such thing as r31 refrigerant. also in your picture you have forgotten a condensor (unless its in the background). and there are 2 things in a refrigerant system (clean and working anyway) refrigerant and oil. with the suction at the top the oil wouldn't get returned to the the compresser and it would seize over time. and with the current running in the mobo and other things it might react with the oil and creat acid. which would then eat away at the motor windings and short out the compressor. it would also eat away any of the copper on the mobo. so this is not a good idea to do.

Olen
07-06-2007, 05:07 AM
The compressor would be the whole unit lifted from a fridge so oil shouldn't be an issue but moving the intake down may well be worth it. A seal is quite possible with a welded steel frame with one side with a gasket for access - think about a cars cylinder head.

R31 is chlorofloromethane and isn't too bad for the environment though I am now leaning more towards R123 as it designed for higher temperatures but lower pressures which makes life easier.

then cools that to ambient temperatures I didn't draw a radiator but it would indeed have one.

Mineral oil wouldn't form acids AFAIK. I'd be using old components anyway as this is more esoteric than a good cooling solution. Water cooling does everything you could ever want and is simpler, I just like fiddling around.

The boy 4rm oz
07-06-2007, 10:34 AM
The problem with vaporchill cooling systems is that the chip its connected to can crack due to the extreme cold. The cold bursts of air on the chip would only make this outcome more likely.

Spawn-Inc
07-06-2007, 04:45 PM
The compressor would be the whole unit lifted from a fridge so oil shouldn't be an issue but moving the intake down may well be worth it. A seal is quite possible with a welded steel frame with one side with a gasket for access - think about a cars cylinder head.

its not the case being sealed thats a real problem is sealing all the wires and what not that are going to be connected to the computer that will be. unless you have access to the glue that compressor makers use to seal the power wires.




Mineral oil wouldn't form acids AFAIK. I'd be using old components anyway as this is more esoteric than a good cooling solution. Water cooling does everything you could ever want and is simpler, I just like fiddling around.

well normally there isn't electronics with current flowing through them in a normal refrigeration system, so who knows what will happpen.

i see getting a proper seal, getting oil back to the compressor, possbily cracking the cpu like The boy 4rm oz said, and the chance that oil might react with the electronics or coatings on them.

to solve the cpu cracking you might strap a heatsink to it and have it spray on that.


do you do any work in the feild?(hvac-r)

Olen
07-06-2007, 06:50 PM
I've messed about with such things a little.

They wouldn't form acids. I'm fairly certain of this, if acids did form it would have to come from the mobo, you have hydrogen, halogens and carbon in the coolent. Its very unlikely that any acid would form due to the difference in enthopies.

I'm swaying away from this idea, I think it would work but I don't think its worth it. It could be done but its too dangerous if it goes wrong. The compounds you use are either moderately toxic or quite flamable - neither good at pressure indoors in a room you will be in. It was meant esoterically anyway and indeed as pointed out the disadvantages outwiegh any benifits.

I think I'll stick with heatpipes.