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Unconventional Liquid Cooling Discussion

Vega

Supreme [H]ardness
Joined
Oct 12, 2004
Messages
7,377
For my next build, I will be seeking another unconventional liquid cooling system. Various questions. Below or above the dew point? Above or below freezing? And always the thorn in the side of such projects: condensation prevention.

Planned system: i7 3960, X79, four 7970's. EK CPU, motherboard and GPU water blocks, Iwaki RD-30 pump.


Option 1:

Use the same sub-zero liquid cooling phase change system as my previous 990X/Quad 3GB 580 build from 2011 (link located in sig).

Pro's:
Will get sub-zero temps for great over clocking.
Dumps the heat outside during summer.
Dumps the heat inside during winter.
Less stress on home HVAC system to offset some of the cost.
Portable if I move.

Con's:
Uses quite a large amount of electricity.
It is loud outside the home.
Serious condensation prevention measures required.


Option 2:

Geothermal cooling loop/tank under ground next to house.

Pro's:
Temperature will not be sub-dew point, but will be much better than traditional indoor radiator water cooling.
Relatively constant temperature around ~10-15C if dug 8 foot deep.
Virtually maintenance free.
Dumps heat outside the home during summer.
Temperature of cooled computer parts should stay just above the dew-point, eliminating condensation prevention.
Very low energy use (just the pump which is required for any water cooled loop)

Con's:
Dumps the heat outside during winter.
Rental of digging/well drilling equipment is costly.
Initial labor requirement is vast.
Copper tube price is quite high.
Non-portable if I move.


Option 3:

Mineral Oil cooled with phase change down near sludge point. I have read mineral oil might become too thick to pump even as high a temperature as 10C. I will have to buy a bottle and do some viscosity tests. There is a computer out there that has run years in mineral oil without problems.

Pro's:
The need and cost for all water blocks is eliminated.
The need for condensation protection for sub dew-point operation is eliminated.
Heat can be dumped outside during summer.
Heat can be dumped inside during winter.
Less stress on home HVAC system to offset some of the cost.
Portable if I move.

Con's:
If mineral oil working temperature only goes as low as 10C, it might be a catch 22 seeing as that is around the point you don't need condensation protection anyway.
Cleaning of parts required for resale.
Unknown reaction to silicone, sometimes a key material used for waterproofing.
Uses quite a large amount of electricity used in conjunction with phase change.
It is loud outside the home.


Option 4:

Traditional indoor water cooling with a large radiator and fan such as from a truck/automobile.

Pros:
No need for condensation protection as going below ambient air temperature is impossible.
Heat is dumped inside during winter.
Simplicity
Low maintenance
Low cost
Least logistics involved and portable if I move.


Con's:
The best cooling possible will be around ~20C or whatever your indoor air temperature is at.
Temperature will fluctuate some as your HVAC system turns on and off to dissipate the heat.
The most stress on home HVAC system of any water cooling solution.
This setup would have the highest temperature delta between components at idle and max load.


Some other thoughts:

I've noticed with my last sub-zero build that I hit max safe voltages on components like the CPU and GPU's way before I even broke 10-15 deg C under 100% load on said components. My understanding is that once you hit a certain voltage on a 24/7 computer, no matter how cold you go the voltage can damage the components and/or seriously degrade their lifespan. So that begs the question, is it even necessary with today's components to cool below the dew point? If not, that alleviates the headache of condensation protection. This first came to light for me when some of the other top members were competing with me for the top benchmarks. They got within a few percentage points of my scores with ambient water (albeit they were some pretty hardcore ambient water setups). So is sub-ambient cooling even necessary besides the "wow" factor and the diminishing returns too great? Especially when you get into condensation prevention territory? Is it just too bad-ass to have 100% load CPU and GPU's operating at 7 deg C in a 24/7 setup? :D

As for if I did go with my original sub-zero cooling system. That brings up the condensation gremlin once more. Before I used Dragon Skin liquid curable rubber. It did prevent condensation but it was also difficult to work with. It had low surface tension and it settled into every low spot and did not coat vertical surfaces too well. It is also very difficult to remove. With that low of temperatures, thick layers of insulation under the dragon-skin were required yet condensation on the outside skin still developed.

Mineral oil would solve the condensation problem, but you get back to the low temperature viscosity problem. Does anyone have any thoughts/experience with mineral oil? I understand aquarium air pumps can be used to circulate the mineral oil over the surfaces of the hot components to great effect.

I've also thought about vacuum sealing. While it doesn't create a true 100% vacuum, it would eliminate most of the moisture. Finding bags, vacuum sealing equipment and a way to vacuum seal all of the connections would be a mighty project in itself.

That brings me to the simplest, cheapest and easiest implementation. An air tight container sealed off with silicone or the like with massive amounts of desiccant inside. This would alleviate any atmospheric pressure issues and the desiccant should drop the air moisture directly contacting the components to below 5%. Surely enough so that water droplets should not form causing shorts.

I will attempt to stay away from any direct surface type conformal coatings as the condensation on top of the coating would be severe at the temperature my last system operated at.

I appreciate any thoughts, suggestions and any experiences with the items in this topic.
 
do what i did i raised my chiller temp form -15f to 65f no condensation and keeps my 3930k coolish and saves me $60 a month on my chiller power casts as the thing only runs a few times and hour now for a few minutes a time. so to recap 3930k at 5ghz 1.425v core 55c load temps and dotn have to woroy about condensation
 
Are you using like an aquarium chiller? If you go that warm in temperature, wouldn't a regular radiator water cooling suffice? 55C seems a bit high.
 
im using a windows unit so all the heat is dumped outside my house. as for the load temps i could get about the same load temps whit just rads but i already had the chiller so not point in changing it. and i have found that if you go below dew point go way below freezing as i have found its easier to control condensation when its freezing then say at 45f where ever thing is sweating instead of just icing. i ran my chiller 24/7 for about 8 months and what i got out of it was only about 400more mhz out of my 955be then on just water never had a problem whit condensation but that's was a $150 cpu this one is a $550 cpu and to me its not worth the risk to go form 5ghz to 5.5ghz+ or the power to run the thing 24/7.
 
Ya, anti-condensation measure are a monster PITA.
 
I don't understand the mineral oil idea. To get good heat transfer, you need a lot of area in direct contact with the heat. That's what a water block does. Seems to me you would need an equivalent "mineral oil block" which would be harder to implement because of viscosity / sludginess.

Just running tubing slightly above the hot components won't transfer near enough heat. And touching the components with the tubing won't transfer enough heat either, and after the tubing melts or burns it will work even less well.

Maybe I don't understand what you're suggesting.
 
I don't understand the mineral oil idea. To get good heat transfer, you need a lot of area in direct contact with the heat. That's what a water block does. Seems to me you would need an equivalent "mineral oil block" which would be harder to implement because of viscosity / sludginess.

Just running tubing slightly above the hot components won't transfer near enough heat. And touching the components with the tubing won't transfer enough heat either, and after the tubing melts or burns it will work even less well.

Maybe I don't understand what you're suggesting.

Mineral oil cannot be used for very low temperature stuff do to viscosity. My thinking is going towards geothermal cooling just above the dew point. This allows relatively cool water temperature of 10-15C, zero energy use and you don't have to worry about condensation prevention.

You could use this stuff, maybe even cool the liquid even further:

http://www.youtube.com/watch?v=Z_X_hgtlJpA

http://www.amsmaterials.com/products/Novec-7000.html

-120C sounds fun.

Engineered fluids are always the way to go until you factor in cost. Mineral oil is used only because it is cheap. Novec 7000 is around $400 a gallon last I read. I have a few emails in with suppliers to get the current cost. But I would need like 10 gallons of the stuff and as you can see you would have to be insane or rich to spend $4000 on fluid for your computer.
 
I think it's possible to get Novec 7000 for $100-$250 a gallon according some forums I google'd. I think though you could do a pretty small system using something like water blocks. If you REALLY cooled this stuff, you can't submerse the MOBO since they probably couldn't operate at such sub-0 temps. Have something like a gravity fed water block from the reservoir and then have a gas tube that takes the boiled Novec to the cooling system.

And Vega, if I was to pick anyone who was "insane or rich to spend $4000" on computer cooling, you're probably going to get picked, haha.
 
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Submerge your components in the oil and chill the water in the loop. That way, you can get your super low temps and the oil will prevent condensation on the components.
 
OMFG I just read your entire build log for the past rig and I am waaaaaay excited to see what magical sorcery and space technology goes into your new build!
 
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