Cooling motherboard via conduction from behind

[entropy]

If I pulled a partial vacuum in my case (assuming air-tight), could I cool the motherboard (including RAM + NB) from behind? I suppose the best way would be conduction cooling using some kind of TIM. The TIM would be cooled with evaporator coil, so it'd reach temps of -30 C. I imagine most of the motherboard would be well-cooled, though I'm not sure about the RAM.

I'm speaking hypothetically here, not in a practical sense.

[n00b 0f l337]

You'd probably need a cascade to get those sorta temps on the back of motherboard.

[entropy]

Yeah, and I've heard capacitors cannot go too low in temp.

But what about -10C or higher?

More for offsetting the insulation of the vacuum, than getting super-cooled mobo components.

[bazx]

closed loop oc chamber gets down to -10

http://www.net7.info/1/beer/20.jpg

http://www.net7.info/1/beer/19.jpg

[[XC] gomeler]

Just curious, why? The amount of work to insure there is a deep enough vacuum so as to not cause condensation would be a verifiable nightmare.

[n00b 0f l337]

You'd be better off filling it with dry nitrogen. Negative pressures very hard to keep ;)

[Exahertz]

first problem would be outgassing. im not sure if the capacitors could handle the pressure differencial as i could see the electrolytic capacitor's internal chemicals atempt to equalize the pressure.

secondly, vacuum is a thermal insulator. with no gas molecules to absorb the thermal energy you loose the process of convection, and any stored heat would only be able to radiate out.

and depending on your level of vacuum carona discharge could become a factor. its funny how i dimenstrated this phenomenon using a cell phone. i took the phone and called my other cell and put it on speaker phone, then i stuck it in a vacuum chamber and started pumping down. at around 4 torr you could hear white noise and someware around 1.5 to 1 torr the phone died.
at a low enough pressure, electrons will jump through nitrogen (and especialy argon) from low to high potentials, and even low potentials will jump short gaps thus forming a short circuit and burning out any sensitive component in series with the arc.

as n00b said, build a nitrogen pumped "dry box". and if you can keep the moisture out well enough you should be able to cool the gas quite a bit.

[n00b 0f l337]

Well as for using nitrogen, charging to atmospheric pressure would remove those problems ;)

[Stigma]

Mineral oil submersion would be a heck of a lot easier to acomplish than keeping a vacuum. it would also solve a lot of the issues with trying to cool the entire motherboard since the oil would carry the heat, especially if you introduce a little bit of circulation. Cooling it from the back would be a very poor method because its so indirect and contact would be poor. Coupled with the vacuum idea its just not practical.

if you "must" cool the whole motherboard instead of just getting some seperate NB and RAM cooling, then go for miineral oil submersion as I said. its a bit messy, but its a heck of a lot more effective and servicable than a vacuum system...

EDIT: Not all cheap capacitors will handle low temps below freezing. Sealed high quality caps would also be highly recommended if you don't want to risk long-term dammage from subersion. There isn't a ton of data to draw from regarding that, but thats what I've heard anyway. That lower quality caps can die from low temps is a known fact tho.

-Stigma

[Exahertz]

Mmmmm, deep fried ram fries and cpu chips :lol:

kinda interesting idea. so much for RMA'ing anything though

edit:
i just found this picture :lol::lol::lol::lol::lol:

http://cache.gizmodo.com/assets/resources/2006/10/dsc03293.jpg

[[XC] gomeler]

The crap the oil is leaching from the board.. yikes. Otherwise funny, just wouldn't eat those chips

[Stigma]

Actually, its not that hard to clean of mineral oil safely... it just takes a little patience and much alcohol (no, not for you! =P)

of course, morally speaking, I would have to agree that it would be hard to RMA any part used in that kinda setup with a clear concience... then again, who needs a concience anyway? ;)

EDIT: Hehe, yea nice pic. must have been a delay, I didnt see it until now.

-Stigma

[ak_47_boy]

A vacuum suck the electrolyte out of capacitors. The whole motherboard will have to be cooled since you have no air cooling anymore.

[zabomb4163]

a guy on these forums had a setup exactly for this purpose. Had silica pellets in the chamber to absorb any moisture he missed and made an interface to allow things like the monitor to connect to the PC inside of the chamber. Keep the power supply outside. Maybe somone else remembers his handle?

[[XC] MarioMaster]

it would just be easier to refrigerate the air entering your computer, that way you wouldn't have to worry about condensation until you switch it off which you'd need to make sure temperatures rise slowly

[[XC] 2long4u]

How about just putting the mobo in a sealed box and have a rather large captube (say from a 5 ton unit) spray right on everything. JK

[Pete]

Spray the mobo with some laqure, then cover it in DICE, -70 there and then problem done