oil cooling

[kookenstein]

in process of designing a cooling system, and was wondering if anyone has used light oil a a cooling medium (eg silicon oil) trying to figure out which would offer better heat transfer, oil or water. failing this i picked up a watercooler at culligan that doesn't work(it freezes, hehe) which will be used

 

[@crilicM@n]

As far as I know, pure water is the best cooling choice, but usually some aditives are required... Don´t think oil would do better... maybe a Chemistry could help you on this doubt, but I bet on water...

 

[Vector]

the cool thing about water is 1.) it has an enormous capacity for absorbing heat (the calorie is based upon the energy required to boil 1 gram of WATER...that means that heat is added to water and it tries its best (and usually succeeds) at maintaining its prior temperature)

and 2, get this--water is everywhere and really cheap to get

the best and most cost-effective way to cool a chip to the extreme is to get a really kick *** refrigeration system and use it with some form of water-cooling solution...you can probably get water down to about -20F or so if you saturate it with salt (non iodized is better) because it's heat capacity rises

chemistry really sucks in college, but you pick up on some semi-interesting things if you stay awake

 

[SP]

Water is best for cooling. The reason water is best is because of it's specific heat capacaty. Specific heat capacaty is a measure of the amount of heat energy that must be absorbed by a given amount of a substance to raise it's temp by a certain number of degrees. In a liquid cooling system we pump a cool liquid into a heat exchanger where it absorbs heat until it's temperature is equalized with the heatexchanger. Then we pump that heated liquid away to a radiator where it is once again cooled and goes back through the system. Anyway, the amount of the heat the liquid can absorb will be dependant on how cool the liquid is when it's pumped into the heat exchanger and it's specific heat capacaty. If your cooling the liquid with a radiator, which is cooled by room temperature air, then the liquid won't go below ambient temperature. So, to get better cooling you need a liquid that has a high specific heat capacaty. Water has a higher specific heat capacaty than most oils. So, all else being equal water will be better.

 

[kookenstein]

thanks alot, looks like i will be modifying the watercooler...should work ok, just have to insulate the bottle. good deal too, 50bucks. if anyone is looking, just check with your local bottled water outlet....l8r

 

[Mr_Goat]

SP has the specific heat of water down...most oils have a specific heat ranging between 0.001-0.02 water on the other hand is 1.000...I've seen and worked on heat transfer for total imersion systems...where most of the components are in a bath of mineral oil that is chilled remotely and pumped in. It's used because it has a resistance of 400-650 Mega ohms not because of its thermal properties (which suck compared to water)

 

[dasouthernocer]

For total emersion which oil would be able to draw away the heat the quickest? Silicone oil, mineral oil or another type? Also how cold can you get silicone oil or mineral oil before it starts turning into gel or solid? Thanks for the input guys.

-William Lucas

 

[Fink]

dasouthernocer (Jan 17, 2001 12:25 p.m.):
For total emersion which oil would be able to draw away the heat the quickest? Silicone oil, mineral oil or another type? Also how cold can you get silicone oil or mineral oil before it starts turning into gel or solid? Thanks for the input guys.

-William Lucas

Silicone oil will freeze about -40C while mineral oil can be cooled down to -100C without freezing (depends on the H2O quantity actually and wether the oil is considered light or heavy). Silicone oils and 'silicone fluid' are mostly for high temperature work (100-350C), i.e. they are not subject to oxidative degradation due to high temp, have limited boil off at said temps and are not prone to spontaneously catching fire - unlike mineral oils. Both have crap heat capacity although thermal transfer of both silicone oil and mineral oil is generaly quite good, better than water. But water with a bit of waterwetter will exceed the oils in both thermal capacity and transfer, plus H2O is cheap, readily available and will not catch fire!

 

[dasouthernocer]

Thanks I'm thinking about trying maybe a 4 or 5 HP compressor too cool the oil with and also and 1/5 - 1/10 compressor for the CPU itself. I'm not sure how cold i'm looking at but it's gonna be a summer project thing so I'll slowly figure this out .

-dasouthernocer