# 3M Novec 7000 Group



## chmodlabs

Testing is done!

https://vimeo.com/37127378


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## Jimbo2032

This is awesome! Is there any evidence that the HFE interacts with any of the insulators on the board? This reminds me of some of the oil immersion experiments and they always had trouble with the electrolytic capacitors seals being degraded by the mineral oil.

Keep up the good work!


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## NoL

I've used the original 3M solution.
The end result is the cost and need to keep a sealed hermetic environment does not outweigh the benefits. Ultimately air cooled servers are more efficient and use less space in 1U rackmount configurations without the need for a condenser. Increasingly, for overclockers, it serves less purpose as it is not a good working fluid, and is prone to gelling. So you get water results at many times the price, difficulty, and encumberance.

It's fun and a cool idea. But also, insulation for sub zero methodologies has progressed incredibly in the last five years. Insulation is simple and does not place permanent marks upon motherboards and rarely results in damage with minimal preparation, something far from this configuration.

Sure is the power recoup nice? If you can produce high enough pressures for a regenerator, yes. Is it viable? Not really.
Also the fluid is often used with masks, as the effects of the fluoroether long term on lung tissue is not yet known or tested.


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## chmodlabs

Quote:


> Originally Posted by *NoL*
> 
> I've used the original 3M solution.
> The end result is the cost and need to keep a sealed hermetic environment does not outweigh the benefits. Ultimately air cooled servers are more efficient and use less space in 1U rackmount configurations without the need for a condenser. Increasingly, for overclockers, it serves less purpose as it is not a good working fluid, and is prone to gelling. So you get water results at many times the price, difficulty, and encumberance.
> It's fun and a cool idea. But also, insulation for sub zero methodologies has progressed incredibly in the last five years. Insulation is simple and does not place permanent marks upon motherboards and rarely results in damage with minimal preparation, something far from this configuration.
> Sure is the power recoup nice? If you can produce high enough pressures for a regenerator, yes. Is it viable? Not really.
> Also the fluid is often used with masks, as the effects of the fluoroether long term on lung tissue is not yet known or tested.


This cooling method is much more efficient than any form of air cooling primarily in concerns to hardware density, and since I was able to produce 40+ psi with one server unit a substancial amount of power could be re-captured. And the method would improve with scaling since more vapor would be produced. The over advantage is that everything operates in a completely sealed loop, removing the step of cooling expelled server air with large HVAC installations. Yes, the chemical is dangerous if inhaled in large quantities, but if the installation was vented properly and sealed properly even if small leaks still ocurred there would be negligible risk at most. And novec 7000 as apposed to your "original 3m solution" is not prone to gelling, the only way gelling could occur is if particulate debris (dust etc) collects in the novec itself and collects while the novec boils away the "build up" could be confused for novec gel. And I'll upload the actual data I collected but in terms of decreasing the energy required to cool servers the novec setup is obviously more efficient. And this system is aimed at high density high load operation, not personal overclocking. And currently used glycol server cooling systems (used by the navy) are much more dangerous to human health than novec will ever be.

Thanks for your input but check your facts and whats being applied first.


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## chmodlabs

Quote:


> Originally Posted by *Jimbo2032*
> 
> This is awesome! Is there any evidence that the HFE interacts with any of the insulators on the board? This reminds me of some of the oil immersion experiments and they always had trouble with the electrolytic capacitors seals being degraded by the mineral oil.
> Keep up the good work!


In regards to interaction with motherboard components there was not much at all. Novec 7000 was developed to clean server hardware, so if you look up the msds as seen here the chemical does not react at all with most metals and common plastics used with computer hardware. In terms of the testing I did I did not observe any novec seeping into capacitors or any other components. Although I had similar interests in seeing how the novec would interact specifically with capacitors. I used some pcb sealant to seal the caps of certain capacitors and left other capacitors un sealed. There was no diference after the novec cooling system ran for over 48 hours straight. With further research I found that the biggest problem with novec 7000 primarily with cheaper foxconn produced server boards when novec gets behind certain IC's and pushes the components off the pcb after vapors build behind said components. Other than that all other components tested very well in the novec, even mosfets and other VRM circuitry.

Thanks for your positive feedback!

If you have any further in depth questions regarding my research post on this theread or PM me any time,
- Chmodlabs


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## NoL

I get your pushing your product, but you might not want to be so callous. You might get input from the throw arounds (throw arounds; I mean, are the people in this section who post "can I put my computer in my fridge" topics five times a week), but the people with thermo degrees and years of experience might chime in if your more hospitable. As to your first claim, your system does not appear to be smaller then a 1U rackmount.

So let's hit your post shall we?
Quote:


> This cooling method is much more efficient than any form of air cooling primarily in concerns to hardware density, and since I was able to produce 40+ psi with one server unit a substancial amount of power could be re-captured. And the method would improve with scaling since more vapor would be produced. The over advantage is that everything operates in a completely sealed loop, removing the step of cooling expelled server air with large HVAC installations. Yes, the chemical is dangerous if inhaled in large quantities, but if the installation was vented properly and sealed properly even if small leaks still ocurred there would be negligible risk at most. And novec 7000 as apposed to your "original 3m solution" is not prone to gelling, the only way gelling could occur is if particulate debris (dust etc) collects in the novec itself and collects while the novec boils away the "build up" could be confused for novec gel. And I'll upload the actual data I collected but in terms of decreasing the energy required to cool servers the novec setup is obviously more efficient. And this system is aimed at high density high load operation, not personal overclocking. And currently used glycol server cooling systems (used by the navy) are much more dangerous to human health than novec will ever be.


First
http://multimedia.3m.com/mws/mediawebserver?mwsId=66666UuZjcFSLXTtlXftMxMVEVuQEcuZgVs6EVs6E666666--
Novec is based on 3M's fluorinert, with a slightly lower boiling point to serve as an R123 replacement in autocascades and "blast injection chillers", mainly due to it's lack of oil pocketing that is seen with r123. So it's pretty close to the same thing. Almost has the same visocosity pattern. The Novec is a little less so. But following its chart in the above manufacturing PDF, by -40C it wouldn't be doing any good.

So, 40psi to power a generator?
Not at anything more then theoretical gains, no. Most of the power you could harness would be in it's heat. A stirling engine and flywheel or static pendulum. That'd help you harness. But, neither of those systems are going to keep removing enough heat that you can simply say you aren't passing heat off to the environment to recondense the working fluid. So it's not replacing AC units. It's simply a separate medium. Same heat load is being applied to the environment. Yes some could be harnessed as energy, but for the most part, no. This isn't the land of theoretical no friction physics.

Also, 40psi is already more pressure then you'd want in one large standing tank, much less a server room of thousands of racks.

Back to the post.
You are fully cooling a server. Every little piece. Which is great for server life, if servers were prone to failure due to heat. But they aren't. Servers are designed and use the highest binned parts, and often run on forced air cooling alone. They're are no actual gains from cooling the mosfets to ~30C. There are no gains from cooling the ram additionally. There are no gains from cooling the power supply. These systems as is, meet their specifications, as they are produced; with air and fans and for the most part, simple aluminum heatsinks.

I'm not to worried about the health risk. So what the NAVY does isn't on this forum. Isn't being pitched, and isn't what we're discussing.

Servers are replaced before they fail, at their rated hour limits, sold and passed down the supply chain or retrofitted, and replaced. Your system does not actually provide a tangible positive effect as compared to the standard of the industry. Yes you added a working fluid that doesn't actually harm the chain. But it's simply another working fluid. If your point is that its easier to vent the heat from the building, it's probably not when you realize your going to have to refit all those buildings. And the cost of your fluid, watercooling systems could easily be employed if a medium is needed.

Additionally in working on your "generator" theory behind the pressure. You have no ability to create a pressure gradient and restriction. So you will end up needing to employ pumps in large installations, to and from the condenser.

I am approaching this in a friendly fashion to see if you've worked around the design limitations. Please respond as such. Ad hominem will get you no where. Mostly because I'm sitting beside a tank of R123 that Novec is designed to replace. And have worked with immersion systems for many years now.


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## chmodlabs

Blade server installations still require a large amount of modification for the buildings where they are held (to account for the massive amounts of HVAC equipment). And again a cpu with no low profile heatsink is still more slim than the height profile of a 1u server unit. The biggest point here can be proved through the heat flux of the transfer media, Novec 7000 is 18 W /m2 and air is around 3 at best. In regards to the size of the test set up, well it's a test set up my intentions were to design a suitable coolant holding tank. In regards to the energy required to condense and transfer the novec there is only a 15C temperature delta from the novec vapor temperature to room temperature (tested at 27C) to start condensing the novec (novec was condensing actively in the coolant tank and while traveling through transfer lines, and theoretically the 20W peltier cooler I was using to condense the vapors easily handled the vapor load and the 40+ psi produced by the unit. This leads to my point that with more units more pressure could be harnessed and converted into energy, and if hardware is immersed properly that pressure will have no negative effect what so ever on the hardware. And although cooling vrm and memory does not result in performance increases cooling those components properly and actively increases their efficiency and reduces the overall power consumption of each unit. And even if fans for each 1u rack unit only consume 7w of power that multiplied by 400 units can become a fair amount of power not to mention again the secondary HVAC that is required. Immersion cooling also allows for server hardware to operate at higher clock speeds which specifically in super computing applications could be a large benefit. In regards to the cost of the fluid I have contacted 3M directly to address this problem. The cost is obviously driven up by a lack of demand, if a market started to develop for novec HFE's undoubtedly it's price per gallon would decrease substantially.

I appreciate your critical thoughts of my research.
- chmodlabs


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## NoL

Just to keep working on this then...
Servers will not be overclocked. Even at our "stable overclocks" CPU's and RAM inherently produce errors on the order of one cycle per hundred thousand. This is the main reason for ECC registered RAM. When they need more power, it's more lateral power, and they add more units.
The 40W peltier on your unit is not cooling the server on it's own. That's a bit of a silly thought. The heat has to leave the system. It's doing so through normal heat transfer through the peltier and other areas. Additionally, capacitors do not enjoy pressure.
While the CPU heatsink would reduce height, you still have RAM and other not so thin items. 1U is as thin as it is going to get.

And if I were you I'd pop a heatsink on there, little reason not to improve the results if it's within the standard form factor.

The point is though, you have created an elaborate system to do something that server could already do for it's entire lifetime. Server hardware doesn't overclock. Doesn't want to overclock. It just wants to live as long as possible and with as few issues. It's designed under high precision with high bin componentry. You have reinvented the wheel so to speak. Ultimately all heat produced needs to leave the system, the environment, and that means out through the change of gas back to liquid. The same loads, if not MORE, are going to be applied due to heat removal from areas that did not need active cooling.

There's no reason for it is the end effect.


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## Nocturin

wow. good discussion and interesting results. I'll never be able to use such a system, but I enjoyed the video


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## chmodlabs

Quote:


> Originally Posted by *Nocturin*
> 
> wow. good discussion and interesting results. I'll never be able to use such a system, but I enjoyed the video


Thanks!
I still have about a gallon of novec left and really dont know what to do with it. I want to develop a semi closed loop system to cool GPU's with it.
- chmodlabs


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## KusH

Quote:


> Originally Posted by *chmodlabs*
> 
> Quote:
> 
> 
> 
> Originally Posted by *Nocturin*
> 
> wow. good discussion and interesting results. I'll never be able to use such a system, but I enjoyed the video
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Thanks!
> I still have about a gallon of novec left and really dont know what to do with it. I want to develop a semi closed loop system to cool GPU's with it.
> - chmodlabs
Click to expand...

Could always send it my way I could always use a new project


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## Nocturin

Why not build a boss sealed mini-itx system like you did with the server and use it as a HTPC?

Build log needed, of course.


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## chmodlabs

Ironically enough since I had a pretty small budget I picked up the opteron 1354 rig for $185 at discount electronics. I wanted to do an htpc SB set up but that wasn't going to compete with a server spec machine for $185. I plan to buy another $285 gallon of novec and get a larger condenser and maybe do a m-atx or itx SBE build. Not sure yet.
A build log would be necessary!
- chmodlabs


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## chmodlabs

Quote:


> Originally Posted by *KusH*
> 
> Could always send it my way I could always use a new project


Well you've got to understand that I had to purchase the novec 7000 through my college chemical engineering proff. and it cost me around $300. In testing I lost about a third of it. And the Novec is very dangerous if not handled correctly or if inhaled. As long as you signed something saying that if you inhale novec vapors and ruined your lungs you wouldn't sue me I could do it. I would give you a bit of a discount though. I'd sell the remaining Novec for around $190. Or trade for a gtx 580 lol.
All kidding aside if I don't find something to do with the novec I will be interested in selling.
- chmodlabs


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## Captain Mayhem

Are there any photos of the rest of the loop? I'm interested in seeing if you used any off-the-shelf hardware for this.


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## chmodlabs

Quote:


> Originally Posted by *Captain Mayhem*
> 
> Are there any photos of the rest of the loop? I'm interested in seeing if you used any off-the-shelf hardware for this.


Well the entire enclosure and generator loop were custom machined and designed.
If you have a better explanation of what "off the shelf" means to you I could explain further.
- chmodlabs


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## Nocturin

Quote:


> Originally Posted by *chmodlabs*
> 
> Well the entire enclosure and generator loop were custom machined and designed.
> If you have a better explanation of what "off the shelf" means to you I could explain further.
> - chmodlabs


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## PeteJM

Interesting discussion, but I believe NoL has a valid point.

Here is how we deal with broken systems in the real world. -chucks broken system out door after taking all sensitive data off-

Do we overclock any of the thousands of servers that we use in the real world? The answer is No, never, ever, ever. With every 10 MHz of an overclock on a bin selected chip, you increase the rate of failure by .01%. Even at a 100 MHz overclock, this means at least one dead system in every thousand, at 500 its 5 in every thousand. When you pay around $600 per server, you theoretically waste money at a certain point.

Awesome theory, but sadly it is just that when compared to most applications now a days. A theory.


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## chmodlabs

Quote:


> Originally Posted by *PeteJM*
> 
> Interesting discussion, but I believe NoL has a valid point.
> Here is how we deal with broken systems in the real world. -chucks broken system out door after taking all sensitive data off-
> Do we overclock any of the thousands of servers that we use in the real world? The answer is No, never, ever, ever. With every 10 MHz of an overclock on a bin selected chip, you increase the rate of failure by .01%. Even at a 100 MHz overclock, this means at least one dead system in every thousand, at 500 its 5 in every thousand. When you pay around $600 per server, you theoretically waste money at a certain point.
> Awesome theory, but sadly it is just that when compared to most applications now a days. A theory.


I understand this. The overclocking perk is much more a consumer application not an industry one. The true aim of this research was to improve efficiency in regards to power consumption entirely and power used to remove heat produced by servers (ie. fans, heatsinks, then large hvac installations)
- chmodlabs


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## PeteJM

Quote:


> Originally Posted by *chmodlabs*
> 
> I understand this. The overclocking perk is much more a consumer application not an industry one. The true aim of this research was to improve efficiency in regards to power consumption entirely and power used to remove heat produced by servers (ie. fans, heatsinks, then large hvac installations)
> - chmodlabs


Makes sense somewhat.


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## 2Faze

am the lead application development engineer in the heat transfer lab at 3M. We make Novec and Fluorinert liquids and I do a lot of research on their use for immersion cooling. Evaporative or 2-phase immersion cooling of servers can make sense if it is done properly. The primary advantages are increased POWER DENSITY and increased ENERGY EFFICIENCY. Air cooling of any variety is limited in this respect. You can have one but at the expense of the other. Liquid cooling in general can give you both but at the expense of varying levels of complexity. Among liquid cooling technologies, 2-phase immersion offers the highest density and the highest thermal efficiency with much lower complexity than its closest competitors.

Google Open Bath Immersion Cooling to learn more. I have some more videos on my YouTube site "petuma1"


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## chmodlabs

Quote:


> Originally Posted by *2Faze*
> 
> am the lead application development engineer in the heat transfer lab at 3M. We make Novec and Fluorinert liquids and I do a lot of research on their use for immersion cooling. Evaporative or 2-phase immersion cooling of servers can make sense if it is done properly. The primary advantages are increased POWER DENSITY and increased ENERGY EFFICIENCY. Air cooling of any variety is limited in this respect. You can have one but at the expense of the other. Liquid cooling in general can give you both but at the expense of varying levels of complexity. Among liquid cooling technologies, 2-phase immersion offers the highest density and the highest thermal efficiency with much lower complexity than its closest competitors.
> Google Open Bath Immersion Cooling to learn more. I have some more videos on my YouTube site "petuma1"


Thanks so much for this input! This sounds really interesting and it's great to hear that the technology is being used in a semi-commercial state. My current energy removal process is currently in the process of being approved for intellectual property rights but to your knowledge have you seen or heard of similar systems?
Thanks again for this information,
- chmodlabs


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## 2Faze

I don't want to discourage you but recovering waste heat by converting to electricty or shaft power usually is not worth the effort. The efficiency is bound by the Carnot efficiency=1-Tc/Th. So even if you can capture the heat as a saturated fluid vapor at 70C (340K), you would have to reject the heat to an ambient at say 20C (290K) to complete your thermodynamic cycle. At best you could capture 1-290/340 = 14% of it. In reality, many other ineffiencies would likely drive this down to <5%. This usually doesnt justify the cost of hardware to recover it. Its far better to capture the heat as efficiently as possible and use that heat directly for some process like desalination, adsorption refrigeration or making beef jerky.


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## chmodlabs

Quote:


> Originally Posted by *2Faze*
> 
> I don't want to discourage you but recovering waste heat by converting to electricty or shaft power usually is not worth the effort. The efficiency is bound by the Carnot efficiency=1-Tc/Th. So even if you can capture the heat as a saturated fluid vapor at 70C (340K), you would have to reject the heat to an ambient at say 20C (290K) to complete your thermodynamic cycle. At best you could capture 1-290/340 = 14% of it. In reality, many other ineffiencies would likely drive this down to <5%. This usually doesnt justify the cost of hardware to recover it. Its far better to capture the heat as efficiently as possible and use that heat directly for some process like desalination, adsorption refrigeration or making beef jerky.


In some of my thermodynamic analysis I came up with similar results, around 12-14% could realistically be re-captured and used to slightly decrease power consumption in large scale server installations. But it still seems like 5% is still a decent amount of energy to recapture.
Thanks for your correspondence,
- chmodlabs


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## NoL

Sorry, but then your "analysis" is off. Carnot cycle isn't a silly numeric value to assign efficiency. It is the upper limit.
Then combined with an inverter, storage or transfer of energy, and just friction within any given recovery device, even 5% might be over stating itself.


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## Captain Mayhem

Quote:


> Originally Posted by *chmodlabs*
> 
> Well the entire enclosure and generator loop were custom machined and designed.
> If you have a better explanation of what "off the shelf" means to you I could explain further.
> - chmodlabs


off-the-shelf meaning: easily obtainable parts such as automotive radiators, swiftech pumps, etc.


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## PhatFree

so this can cool a cpu without a heat sink, thats straight up crazt


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## GKing

This is a great discussion.

I will apologize in advance if this question sounds a little ignorant but, at the end of the day would a commercial version of your 'novec cooled unit' save money in a commercial server farm by removing the cost of a large scale HVAC system and the associated cost of running it?

I understand the discussion around efficiency of the unit, removal of heat and alternatives etc but at the end of the day, if I was a big commercial player I couldn't care less as long as your saving me a big stack of cash and your units are reliable.

So, would your unit be competitively priced? Could I ditch my HVAC system and the cost associated with running it?

Cheers
G


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## Nocturin

That was a heck of a necro, none-the-less I'm interested in an answer too







.


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## kreeuwijk

There is actually a company that is selling Novec-cooled blade servers today: www.iceotope.com
Video here: http://www.youtube.com/watch?v=N3gCavl2Y6U

The solution seems well designed. Drip free, completely sealed and low pressure (0.2 bar). Only 80 watts required to cool a 20kWatt rack full of blades. What do you guys think? Is this a viable implementation of the technology?

Regards,
Kevin


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## sortableturnip

Would love to see if Novec could be used in a closed loop environment similar to a H100 but without the pump. Put the rad in a position higher than the cpu block and let the liquid boil and re-condense in the rad.


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## vSaKv

Quote:


> Originally Posted by *sortableturnip*
> 
> Would love to see if Novec could be used in a closed loop environment similar to a H100 but without the pump. Put the rad in a position higher than the cpu block and let the liquid boil and re-condense in the rad.


Excellent Idea, I start reading about this possibilities like 2 weeks ago. Now I'm waiting for parts to come up and build first pumpless system. My goal is build highly effective cooling system, with low to 0db noise level. I will post some pictures after building it up, with some temps reading. May be I can build them for sale in future.


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## flamingfury472

Hello everyone! I apologize for my lack of knowledge on this subject. I've read through everyone's posts on this thread and it really sounds like this chemical has a very cost effective and practical use, although its usefulness just hasn't been fully "unlocked" so to speak. Again my comments are vague and ambiguous at best, and I apologize for that.

I've been working on a theory of my own yet on a consumer level. Extreme overclocking set aside would using this chemical be practical if used on a water cooling line?
Lets say we take out the triple and quadruple radiator/fan stacks we see a lot of in a loop and replace it with a concept unit. This unit consisting of waterblockeltier:heatsink:Novec 7000:heatsinkeltier:heatsink:fan. (heat transfer from left to right or bottom to top) All of this in a semi compact tube. This tube looking somewhat like a resevoir size "Bacta Tank". ;-)

My theory proposes that the Novec controls the "spiking" in heat. With using a vertical set-up you could actually see the liquid level in the mini-tank fluctuate. We go from major fan configurations to using just a small fan at the top of the mini-tank. Nothing is submerged. Were just capitolizing on Novec's low boiling point and cooling the usual array of components i.e. CPU, GPU, RAM,& MOSFET, and keeping everything at a steady average of ~37C.

Any questions or comments are wanted. Please be critical. I'm considering on building a mockup and testing everything out myself once my funds come in. I just hope my idea doesnt prove futile and a waste of time.


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## Traches

Anytime you are dealing with phase change in a closed loop you're dealing with pressure, which could work but it would be a bit more complicated than what you have described. I don't think standard watercooling components would be much use.

Phase change issues aside, this wouldn't get you very good temps. The best blocks give you a CPU temp 30-40 degrees above your coolant temp while at load. The water in a good loop never gets more than about 10C above room temperature, so by operating at 37c (or more, depending on pressure) your temps will be worse.

Neat idea though!


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## flamingfury472

so running the water in the loop past a chillied water block wouldnt essentially chill the water itself?


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## Traches

Oh wow, I completely misunderstood your idea the first time I read it. I had it in my head that you wanted to use novec as a coolant in your loop, sorry!

I'll be honest, I don't know enough about peltiers to say how plausible it is... But what makes you think the heat sink + novec + heatsink combo will perform better than a simple heat sink in ambient air? The second peltier?


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## flamingfury472

I was thinking of using the Novec inbetween the two peltier to help control heat "spiking". Say there is a sudden jump in heat from the gpu or cpu going into full load, I would think that with something like this in the loop somewhere it would help level out the overall temp. So instead of seeing the temp jump to an immediate 70C or 80C the peltier in the line would actually cool the heat spike faster than a regular fan/rad or a small heatsink on the peltier. This idea certainly isnt efficient on the pocketbook by any means but i think it would make for an interesting show inside the case as well as serve some minor function.

Oh and sorry for the confusion. I'm horrible at explaining things in adequate detail.


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## Traches

Well, in my experience watercooling heat spiking isn't a problem-- water temperature changes over the course of minutes, not seconds. I think you're better off trying to improve your overall ability to move heat.

That said, you could be on to something-- maybe there's a way to use TECs and novec 7000 to increase the heat differential between your heatsink/rad and the ambient air, allowing you to dissipate more heat with less airflow. Maybe a series of TEC chilled waterblocks, hot side immersed in a small tank of novec, with a condenser at the top?


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## flamingfury472

Yea thats exactly how pictured the setup to begin with. Maybe not for the same reasons but hey thats how most great things are found; on our way to finding something else.
I just wish i had the cash to fund such a setup. If you see anything like that get put into play, please let me know. Theres always satisfaction knowing your idea works even if you cant build it yourself.


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## technogiant

I make no claim to be a server cooling expert of any type but can see one point of great value in improving the cooling of servers, that is power consumption. Any given processor at a given clock speed will consume less power when it is held at a lower temperature. This is because electrical leakage in the silicon is lower at lower temps and so less current is drawn and hence less power used. As I understand power consumption is a major cost for large servers I would have thought this a very important point.

Just to confirm what I'm saying here are two graphical representations of power consumption vs temperature........lower temps can lead to considerable power savings.

http://imageshack.us/photo/my-images/846/prestler.jpg/

Uploaded with ImageShack.us

http://imageshack.us/photo/my-images/189/powertemp.png/

Uploaded with ImageShack.us


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## ramicio

But you won't save power if you need something that takes energy to keep them that cool. If ambient can keep them that cold, then it's worth it, but building something like a phase change system to keep the air that cool is going to burn more energy.


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## technogiant

True, if you are using power hungry methods to cool the novec then there is no point.

But if just using ambient air to re condense the novec then that woud not be the case.

The Novec method would remove the cooling bottle neck from the component heat transfer level and at least give the possibility of lower component temperatures should the "upstream" cooling apparatus be adequate.

In current systems lower component temps are limited by the ability to remove heat from the component not by the subsequent disposal of it.


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## mmbrowncow

Great work on using Novec.

Please see the following in a very detailed write-up re: Novec/Florinert and Elastomer interactions. Very enlightening.

TL;DR: Please only use Butyl or Natural Rubber elastomers in contact with Novec. Others will get dissolved and cause big probs.

http://detector-cooling.web.cern.ch/detector-cooling/data/3M_FAQ_Fluorinert.pdf


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## ZytheEKS

I'm curious to see how a subzero liquid immersion cooling system would perform.

http://multimedia.3m.com/mws/mediawebserver?mwsId=66666UuZjcFSLXTtlXftMxMVEVuQEcuZgVs6EVs6E666666--

This fluid seems to have an extremely low freezing point of 153kelvin (-120celsius) and it's dielectric. Isn't the only weakpoint in current subzero cooling designs the way heat is transferred from the device to the the coolant the coldplate, or heatsink?

Using this fluid subzero in a submerged liquid cooling loop will completely negate this factor, and combined with some submerged fans to circulate this fluid you could reduce the evaporation rate so that it could be controlled with just a couple peltiers on the highest physical point in the submerged tank

Any thoughts?


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## mmbrowncow

Quote:


> Originally Posted by *ZytheEKS*
> 
> I'm curious to see how a subzero liquid immersion cooling system would perform.
> 
> http://multimedia.3m.com/mws/mediawebserver?mwsId=66666UuZjcFSLXTtlXftMxMVEVuQEcuZgVs6EVs6E666666--
> 
> This fluid seems to have an extremely low freezing point of 153kelvin (-120celsius) and it's dielectric. Isn't the only weakpoint in current subzero cooling designs the way heat is transferred from the device to the the coolant the coldplate, or heatsink?
> 
> Using this fluid subzero in a submerged liquid cooling loop will completely negate this factor, and combined with some submerged fans to circulate this fluid you could reduce the evaporation rate so that it could be controlled with just a couple peltiers on the highest physical point in the submerged tank
> 
> Any thoughts?


I'd only be concerned about viscosity of the liquid. Viscosity is graphed in the post I made above. Take a look.


----------



## technogiant

Quote:


> Originally Posted by *mmbrowncow*
> 
> I'd only be concerned about viscosity of the liquid. Viscosity is graphed in the post I made above. Take a look.


The viscosity is lower than that of water.......it only approaches the viscosity of water at standard temps/pressures when the novec 7000 it is at -60c


----------



## ZytheEKS

Quote:


> Originally Posted by *mmbrowncow*
> 
> I'd only be concerned about viscosity of the liquid. Viscosity is graphed in the post I made above. Take a look.


Quote:


> Originally Posted by *technogiant*
> 
> The viscosity is lower than that of water.......it only approaches the viscosity of water at standard temps/pressures when the novec 7000 it is at -60c


So long as the pump you're using can handle the viscosity, and your fans in the submerged tanks can properly circulate the fluid, I wouldn't imagine a higher viscosity would be a significant issue, so long as it isn't ridiculously thick. As previously stated it only seems to get as thick as water at -60, and any TEC or phase change cooler that could get lower than -60 would be pretty damn powerful.


----------



## ZytheEKS

Quote:


> Originally Posted by *technogiant*
> 
> True, if you are using power hungry methods to cool the novec then there is no point.
> 
> But if just using ambient air to re condense the novec then that woud not be the case.
> 
> The Novec method would remove the cooling bottle neck from the component heat transfer level and at least give the possibility of lower component temperatures should the "upstream" cooling apparatus be adequate.
> 
> In current systems lower component temps are limited by the ability to remove heat from the component not by the subsequent disposal of it.


What if they built a reactor cooler, with some type of heat exchangers?

A reactor cooler, or as it's more commonly known in the computer cooling world, a Bong Cooler have been known to achieve temps of up to 9 degrees below ambient. If you could find a proper way to use a heat exchanger to use a liquid cooling loop to condense the Novec 7000, then you could in theory use it with no more power draw than a water cooling loop.


----------



## technogiant

Quote:


> Originally Posted by *ZytheEKS*
> 
> What if they built a reactor cooler, with some type of heat exchangers?
> 
> A reactor cooler, or as it's more commonly known in the computer cooling world, a Bong Cooler have been known to achieve temps of up to 9 degrees below ambient. If you could find a proper way to use a heat exchanger to use a liquid cooling loop to condense the Novec 7000, then you could in theory use it with no more power draw than a water cooling loop.


Would seem like an ideal solution, they have to use a condenser to cool and re-condense the vapor generated at the components, why not go that step further and force evaporative cooling of the main body of liquid, and novec 7000 would be ideal for this as having a boiling point of 34c would tend to evaporate easily, obviously there would have to be a two stage cooling process as your novec system would have to be sealed.....the second stage cooling system could also be a bong cooling system....like the idea.


----------



## ZytheEKS

Quote:


> Originally Posted by *technogiant*
> 
> Would seem like an ideal solution, they have to use a condenser to cool and re-condense the vapor generated at the components, why not go that step further and force evaporative cooling of the main body of liquid, and novec 7000 would be ideal for this as having a boiling point of 34c would tend to evaporate easily, obviously there would have to be a two stage cooling process as your novec system would have to be sealed.....the second stage cooling system could also be a bong cooling system....like the idea.


I was thinking more along the lines of using long tube like radiators, and having an intake from the novec sealed chamber at the top, and it would have a fan blowing the novec vapors down the radiator through the fins. THen use a basic water cooling loop, using a reactor cooler to cool the water, then use the water in combination with radiators (acting as heat exchangers) to condense the novec.

The setup itself might take a bit of space, but it would definitely be VERY energy efficient. Though I guess you would also need to factor in the cost of keeping the water cooling loop filled with a decent amount of fluid, as the entire point of reactor coolers is to physically remove the hot fluid. It would be an interesting project, if only I had the money XD


----------



## jaov2k

I've been toying with this idea of the Novec 7000. I even called and spoke to the 3M rep in the area so I could get a 4oz sampleto experiment with it and different materials.

My original idea was to make an acrylic case (a single piece "desktop" style), put all the components in it, and seal it tight with a copper lid. The lid would have some fins and such, letting the novec condense back into the case.

The reason I actually entertained the idea was the fact that I live in an A/C environment that is constantly at 22C (72F), permitting the Novec to actually condense.

There's unfortunately, a very REAL problem with the Novec vs all other cooling solutions, which has already been mentioned, but is worth mentioning again. It's $400 per gallon.

There are many alternative cooling solutions for that kind of money. Will they be fanless? Probably not. Will they be power saving? Nope. The attractiveness of the Novec is that it cools your entire PC, not a few components, its quiet, and its passive. Unfortunately, even the smallest of custom made cases will require at the very least 2 gallons of the stuff (12"x9.6"x7"). This now puts you into the $800 area. If you start doing the return on investment math of the Novec vs the fans/water, phase change solution I'm sure you'll find that $800 will take longer to pay itself off vs kilowatt hours of the alternatives over the life of the PC. In other words, over an assumed 5 year life of the PC, it would be cheaper to operate a compressor and fans, than to shell out $800 for a couple of gallons of this stuff.

Alternatives do exist which have also been mentioned, the Dupont Vertrel stuff. I don't know the per gallon cost of this. The only con is the boiling point of the dupont vs the 3M, with the Dupont being higher at like 56C, I think.

One thing I did like about the Vertrel vs the Novec was its compatibility with many more plastics/rubbers than Novec. Novec only likes to play with hard plastics, meaning you have to use nylon gaskets or some of the pour in place gasket forming stuff. Where as the Vertrel does work with silicon rubbers.

A con for the Vertrel is that its not compatible with acrylic. this isn't much of an issue, but when it comes to case fabrication on a small scale acrylic is much easier to work with than the thermal plastics. Plus acrylic has some really cool optical/light properties that the thermals dont have. Novec is compatible with acrylic.

Anyways. This is as far as I've gotten with a Novec 7000 solution. I'm not sure if I plan to continue with it due to the upfront cost and the lack of justification of the long term. I'm sure not cooling the cmos battery or the PCI slots won't kill my mobo over the 5 year life of the PC.

-jaov2k


----------



## ZytheEKS

Quote:


> Originally Posted by *jaov2k*
> 
> I've been toying with this idea of the Novec 7000. I even called and spoke to the 3M rep in the area so I could get a 4oz sampleto experiment with it and different materials.
> 
> My original idea was to make an acrylic case (a single piece "desktop" style), put all the components in it, and seal it tight with a copper lid. The lid would have some fins and such, letting the novec condense back into the case.
> 
> The reason I actually entertained the idea was the fact that I live in an A/C environment that is constantly at 22C (72F), permitting the Novec to actually condense.
> 
> There's unfortunately, a very REAL problem with the Novec vs all other cooling solutions, which has already been mentioned, but is worth mentioning again. It's $400 per gallon.
> 
> There are many alternative cooling solutions for that kind of money. Will they be fanless? Probably not. Will they be power saving? Nope. The attractiveness of the Novec is that it cools your entire PC, not a few components, its quiet, and its passive. Unfortunately, even the smallest of custom made cases will require at the very least 2 gallons of the stuff (12"x9.6"x7"). This now puts you into the $800 area. If you start doing the return on investment math of the Novec vs the fans/water, phase change solution I'm sure you'll find that $800 will take longer to pay itself off vs kilowatt hours of the alternatives over the life of the PC. In other words, over an assumed 5 year life of the PC, it would be cheaper to operate a compressor and fans, than to shell out $800 for a couple of gallons of this stuff.
> 
> Alternatives do exist which have also been mentioned, the Dupont Vertrel stuff. I don't know the per gallon cost of this. The only con is the boiling point of the dupont vs the 3M, with the Dupont being higher at like 56C, I think.
> 
> One thing I did like about the Vertrel vs the Novec was its compatibility with many more plastics/rubbers than Novec. Novec only likes to play with hard plastics, meaning you have to use nylon gaskets or some of the pour in place gasket forming stuff. Where as the Vertrel does work with silicon rubbers.
> 
> A con for the Vertrel is that its not compatible with acrylic. this isn't much of an issue, but when it comes to case fabrication on a small scale acrylic is much easier to work with than the thermal plastics. Plus acrylic has some really cool optical/light properties that the thermals dont have. Novec is compatible with acrylic.
> 
> Anyways. This is as far as I've gotten with a Novec 7000 solution. I'm not sure if I plan to continue with it due to the upfront cost and the lack of justification of the long term. I'm sure not cooling the cmos battery or the PCI slots won't kill my mobo over the 5 year life of the PC.
> 
> -jaov2k


We're talking about using it in a rig for a server, not for a home based gaming desktop or something like that. For a PC yeah the price of the Novec 7000 will definitely outweigh it's performance, but when we're talking about a large scale server rig they already spend lots of money on a nice HVAC system to keep ambient temps in the server room low, so if you could have the total cost of the Novec 7000 cooling rig + fluid be around the same price as an HVAC system, then it becomes practical. You could also devise a way to use liquid cooling to keep it below 40 degrees(using TECs probably, and have it's radiator setup outside, so the heat is deposited directly out of the building. So if you get the price to be about the same, then any energy saved from lower temps will VERY quickly add up, as there was the same price investment









It's also possible to use this in a subzero liquid cooling system, as it's freezing temp is -120, which it would be VERY practical, as you would need probably about 1/3rd a gallon, assuming you're using it in a standard loop and not submerged subzero. This is something the DuPont's Vertel can not do. You'd need to custom fashion a CPU waterblock with a TEC on the top, to condense any evaporation that may occur.


----------



## jaov2k

Ah. Indeed, in commercial application this is a very tempting solition. Considering the price of an HVAC along with its O&M.


----------



## ZytheEKS

Quote:


> Originally Posted by *jaov2k*
> 
> Ah. Indeed, in commercial application this is a very tempting solition. Considering the price of an HVAC along with its O&M.


Yup, the actual price of the cooling setup would probably be the same, more or less, but hey you're going to get lower temps, so less electricity used.


----------



## technogiant

Hi Novec group, hope you don't mind me posting here with this but I just wanted to get opinion from people on my new project as it is similar to Novec cooling in many respects ie submersion/phase change.

So I'm linking to my new project thread....there is no real need to read the entire thread as it contains much sound boarding and discussion of alternative methods just my last post would be sufficient to outline the final build design.

Would appreciate your views as the cooling methodology is very similar.

http://www.overclock.net/t/1346823/subambient-full-submersion-phase-change-cooled-pc


----------



## OCAddict

Quote:


> Originally Posted by *chmodlabs*
> 
> I would like to expand my research for next year with some better, possibly gaming hardware on the M-ATX form factor with some high end components to really showcase this HFE chemical lineup and with an increased demand of OC'ing gamers could possibly drop the current $285 per gallon price of this chemical. CHmodlabs


Interesting, but when you bring OC'ing gamers into the picture with setups like mine overclocked to 5ghz you'd probably need much more of the fluid covering the CPU especially for the boiling going on at the stock clock you tested?

I'm curious as to the vapors you capture are they reprocessed back into a liquid state so no fluid is lost at all?

Because at a cost of $285 per gallon and what's going to happen at a 5ghz CPU overclock, if the vapor cannot be converted with zero loss, overclockers will not be lining up to try this?

How harmful is this vapor if it escapes into the atmosphere?

My present cooling cost me electrically, but not health wise?

No matter how good various cooling solutions look, you just don't get something for nothing.


----------



## ZytheEKS

Quote:


> Originally Posted by *OCAddict*
> 
> Interesting, but when you bring OC'ing gamers into the picture with setups like mine overclocked to 5ghz you'd probably need much more of the fluid covering the CPU especially for the boiling going on at the stock clock you tested?
> 
> I'm curious as to the vapors you capture are they reprocessed back into a liquid state so no fluid is lost at all?
> 
> Because at a cost of $285 per gallon and what's going to happen at a 5ghz CPU overclock, if the vapor cannot be converted with zero loss, overclockers will not be lining up to try this?
> 
> How harmful is this vapor if it escapes into the atmosphere?
> 
> My present cooling cost me electrically, but not health wise?
> 
> No matter how good various cooling solutions look, you just don't get something for nothing.






Does that answer your question?

Another nice thing about this fluid is it freezes at -120celcius, and at -100 celcius it approaches the viscosity of water, meaning if you could make a completely air tight loop with a reconsidering capillary to account for boil off you could make a subzero liquid loop.


----------



## knowyoutang

With further research I found that the biggest problem with novec 7000 primarily with cheaper foxconn produced server boards when novec gets behind certain IC's and pushes the components off the pcb after vapors build behind said components. Other than that all other components tested very well in the novec, even mosfets and other VRM circuitry.


----------



## ZytheEKS

Quote:


> Originally Posted by *knowyoutang*
> 
> With further research I found that the biggest problem with novec 7000 primarily with cheaper foxconn produced server boards when novec gets behind certain IC's and pushes the components off the pcb after vapors build behind said components. Other than that all other components tested very well in the novec, even mosfets and other VRM circuitry.


Yup, some people combated this buy tigging them with a glue gun so that bubbles can't form. Problem is that the glue in a glue gun has a habit of expanding/contracting. Same problem there.

There are some fixes with some fillers, but it's just a pain.


----------



## vlc

Quote:


> Originally Posted by *PeteJM*
> 
> Interesting discussion, but I believe NoL has a valid point.
> 
> Here is how we deal with broken systems in the real world. -chucks broken system out door after taking all sensitive data off-
> 
> Do we overclock any of the thousands of servers that we use in the real world? The answer is No, never, ever, ever. With every 10 MHz of an overclock on a bin selected chip, you increase the rate of failure by .01%. Even at a 100 MHz overclock, this means at least one dead system in every thousand, at 500 its 5 in every thousand. When you pay around $600 per server, you theoretically waste money at a certain point.
> 
> Awesome theory, but sadly it is just that when compared to most applications now a days. A theory.


Is that error rate also true for a well cooled system?


----------



## FROZENPC

This stuff is 340 Dollars a gallon..... im no mathematician but given that it evaporates (due to the phase change of liquid to gas), one would have to refill the server, a task all on its own, and they will need MULTIPLE gallons. running at 24hrs all year...
According to my magical potato calculator that comes out to: WAY TOO MUCH FRICKEN MONEY,


----------



## ZytheEKS

Quote:


> Originally Posted by *FROZENPC*
> 
> This stuff is 340 Dollars a gallon..... im no mathematician but given that it evaporates (due to the phase change of liquid to gas) *, one would have to refill the server*, a task all on its own, and they will need MULTIPLE gallons. running at 24hrs all year...
> According to my magical potato calculator that comes out to: WAY TOO MUCH FRICKEN MONEY,


Holy mother of thread necros.









Well, for the sake of indulging logics, you're missing the point of an evap cooler. The coolant would boil off the components, re-condense, and fall/be pumped back into the vapor chamber. This is all in a closed air tight chamber, it would not need to be refilled at all. Aside from all thermal improvements this might yield over copper heatsinks and fans, which would be huge and thus longer hardware lifespan, there are several benefits to this. The most prominent is the heat could be vented straight outside. This eliminates the need for an expensive heating and ventilation system typically used for server rooms. Another benefit is the reduction in electrical cost the cooling system. Instead of having a bunch of high power fans in the back of every server blade, you'd just need a method of pumping evaporated fluid into the recondensing chamber, i.e. a bunch of copper coils used to exchange heat. Since fluid will keep flowing into the recondensing chamber liquid coolant would naturally be pumped back to the evap chambers. So now you have a lack of expensive hvac, which may justify the expense needed for the phase change fluid, very inexpensive electrical cost needed to cool the the system, as well as longer hardware life.

This is the primary argument here. The primary reason novec 7000 is so expensive isn't because it's some super fluid, it's because there's so little demand for it, and isn't easy to manufacture. If server racks were to utilize a method like this increase demand would drive down the price quite significantly, which was addressed somewhere in the few dozen comments in the thread. This is, of course, all theoretical and thought about just for poops and giggles. I'm fairly certain everyone in this hobby would giggle a little if Novec 7000 was obtainable to your standard enthusiast.

-Z


----------



## FROZENPC

Quote:


> Originally Posted by *ZytheEKS*
> 
> Holy mother of thread necros.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Well, for the sake of indulging logics, you're missing the point of an evap cooler. The coolant would boil off the components, re-condense, and fall/be pumped back into the vapor chamber. This is all in a closed air tight chamber, it would not need to be refilled at all. Aside from all thermal improvements this might yield over copper heatsinks and fans, which would be huge and thus longer hardware lifespan, there are several benefits to this. The most prominent is the heat could be vented straight outside. This eliminates the need for an expensive heating and ventilation system typically used for server rooms. Another benefit is the reduction in electrical cost the cooling system. Instead of having a bunch of high power fans in the back of every server blade, you'd just need a method of pumping evaporated fluid into the recondensing chamber, i.e. a bunch of copper coils used to exchange heat. Since fluid will keep flowing into the recondensing chamber liquid coolant would naturally be pumped back to the evap chambers. So now you have a lack of expensive hvac, which may justify the expense needed for the phase change fluid, very inexpensive electrical cost needed to cool the the system, as well as longer hardware life.
> 
> This is the primary argument here. The primary reason novec 7000 is so expensive isn't because it's some super fluid, it's because there's so little demand for it, and isn't easy to manufacture. If server racks were to utilize a method like this increase demand would drive down the price quite significantly, which was addressed somewhere in the few dozen comments in the thread. This is, of course, all theoretical and thought about just for poops and giggles. I'm fairly certain everyone in this hobby would giggle a little if Novec 7000 was obtainable to your standard enthusiast.
> 
> -Z


AHH yes is see know... but servers get upgrades. and that means dumping this stuff. IDK i think its fricken cool!
but i also think it CAN POSSIBLY lead so some very expensive situations.


----------



## SpecTRe-X

Quote:


> Originally Posted by *FROZENPC*
> 
> AHH yes is see know... but servers get upgrades. and that means dumping this stuff. IDK i think its fricken cool!
> but i also think it CAN POSSIBLY lead so some very expensive situations.


It would depend on how it was used. If you mount the hardware on trays then you could have hundreds or thousands of trays submerged in a bath. unless the bath is contaminated somehow you wouldn't have to replace the fluid. You also have to remember that as demand increases the substance becomes cheaper to buy because it isn't a special and limited use item anymore.


----------



## exousia

I thought you guys might enjoy this video of a guy at Quakecon this year who built his PC (in 2 years) submersed in Novec 7000.

Pretty awesome build.

https://www.facebook.com/nicholas.w.hebert/videos/vb.500382781/10154088807292782/?type=3


----------



## PDXMark

Anyone done any pressurized glycal cooling systems yet?


----------



## RnRollie

Quote:


> Originally Posted by *PDXMark*
> 
> Anyone done any pressurized glycal cooling systems yet?


Not sure what you're asking, but I suspect NASA or Skunkworks has done something like it already


----------



## PDXMark

Quote:


> Originally Posted by *RnRollie*
> 
> Not sure what you're asking, but I suspect NASA or Skunkworks has done something like it already


Basically a water Glycal mix under pressure. Pressurized cooling is more efficient then non-pressurized. Even if it's just 8 to 12 psi.


----------



## trisorion

I am just trying to wrap my head around the thermodynamics here. Correct me if I am wrong but this is my understanding for a sealed container.
1)If the enclosure has enough heat sinking to remove all the heat that is being generated, then the Novec fluid, the Novec gas and the surface of all the components stay at exactly the boiling point temperature. However, because the components all have some limited thermal conductivity from their silicon junction to the outside of their case, they are all internally somewhat hotter than the boiling point.
2)If the enclosure does not have enough heat sinking to remove all the heat then the temperature and pressure inside the container will increase. This will continue until the enclosure fails, or a new steady state heat transfer balance is achieved. A balance could be achieved because increased pressure --> increased boiling point temperature --> increased delta T between the interior of the enclosure and the atmosphere --> increased heat transfer capability of the heat-sink.

So why do people use Novec 7000 which boils at 34 degrees C when there are other formulations available? Lets say your room is 20 C ambient and you are cooling the enclosure with air. You are only working with a 14 degree C temperature difference. That is small and your heatsink would have to be really overkill to remove all the heat. So the likely scenario is that the entire vessel starts increasing in pressure and temperature. I have heard people report pressures as high as 40 PSI when cooling an overclocked motherboard.

Let us use the Clausius-Clapeyron Equation:
ln (P1 / P2) = (ΔH / R) (1/T2 - 1/T1)

Solve for T2
P1 = 760 mmhg = 101 Kpa = the vapor pressure of any substance at its boiling point by definition = atmospheric pressure
P2 = 40 psi guage = 276 Kpa gauge = (276+101) Kpa absolute = 377 Kpa absolute
ΔH = 142 kJ/kg = 142 kJ/kg * 0.2kg/mole = 28.4 kJ/mole = Novec 7000 latent heat of vaporization from http://multimedia.3m.com/mws/media/65495O/3mtm-thermal-management-fluids.pdf?&fn=bro_heattrans.pdf
R = 8.3145 J/mol·K = the ideal gas constant
T1 = 34 Celsius = 307 Kelvin

http://www.wolframalpha.com/input/?i=ln%28377+Kpa%2F101+Kpa%29+%3D+%28%2828.4+kJ%2Fmole%29%2F%288.3145+J%2Fmol%C2%B7K%29%29*%281%2F%28307+kelvin%29+-+1%2F%28x+kelvin%29%29&a=UnitClash_*J%2Fmol%C2%B7K.*JoulesPerMoleKelvin--&a=UnitClash_*Kpa.*Kilopascals.dflt--

T2 = 348 kelvin = 75 degrees celsius

So using Novec 7000 creates a high pressure potentially 3rd degree burn inducing bomb. But using one of the formulations with a higher boiling point, perhaps 76 C like Novec 7200, would have nearly identical cooling performance without elevated pressure. Right?

As an aside I am interested in using this stuff on some power electronics which generally have a much higher maximum temperature than PC components. In researching this post I noticed that pure isopropyl alcohol is non-conductive, has a boiling point low enough that power electronics would be fine in it and is cheap. Too bad its flammable, but I only need a few tablespoons in my application, so I might try it anyways. http://www.panachem.com/msds/iso_propyl_alcohol_IPA.pdf


----------



## ZytheEKS

Quote:


> Originally Posted by *trisorion*
> 
> I am just trying to wrap my head around the thermodynamics here. Correct me if I am wrong but this is my understanding for a sealed container.
> 1)If the enclosure has enough heat sinking to remove all the heat that is being generated, then the Novec fluid, the Novec gas and the surface of all the components stay at exactly the boiling point temperature. However, because the components all have some limited thermal conductivity from their silicon junction to the outside of their case, they are all internally somewhat hotter than the boiling point.
> 2)If the enclosure does not have enough heat sinking to remove all the heat then the temperature and pressure inside the container will increase. This will continue until the enclosure fails, or a new steady state heat transfer balance is achieved. A balance could be achieved because increased pressure --> increased boiling point temperature --> increased delta T between the interior of the enclosure and the atmosphere --> increased heat transfer capability of the heat-sink.
> 
> So why do people use Novec 7000 which boils at 34 degrees C when there are other formulations available? Lets say your room is 20 C ambient and you are cooling the enclosure with air. You are only working with a 14 degree C temperature difference. *That is small and your heatsink would have to be really overkill to remove all the heat.* So the likely scenario is that the entire vessel starts increasing in pressure and temperature. I have heard people report pressures as high as 40 PSI when cooling an overclocked motherboard.
> 
> Let us use the Clausius-Clapeyron Equation:
> ln (P1 / P2) = (ΔH / R) (1/T2 - 1/T1)
> 
> Solve for T2
> P1 = 760 mmhg = 101 Kpa = the vapor pressure of any substance at its boiling point by definition = atmospheric pressure
> P2 = 40 psi guage = 276 Kpa gauge = (276+101) Kpa absolute = 377 Kpa absolute
> ΔH = 142 kJ/kg = 142 kJ/kg * 0.2kg/mole = 28.4 kJ/mole = Novec 7000 latent heat of vaporization from http://multimedia.3m.com/mws/media/65495O/3mtm-thermal-management-fluids.pdf?&fn=bro_heattrans.pdf
> R = 8.3145 J/mol·K = the ideal gas constant
> T1 = 34 Celsius = 307 Kelvin
> 
> http://www.wolframalpha.com/input/?i=ln%28377+Kpa%2F101+Kpa%29+%3D+%28%2828.4+kJ%2Fmole%29%2F%288.3145+J%2Fmol%C2%B7K%29%29*%281%2F%28307+kelvin%29+-+1%2F%28x+kelvin%29%29&a=UnitClash_*J%2Fmol%C2%B7K.*JoulesPerMoleKelvin--&a=UnitClash_*Kpa.*Kilopascals.dflt--
> 
> T2 = 348 kelvin = 75 degrees celsius
> 
> So using Novec 7000 creates a high pressure potentially 3rd degree burn inducing bomb. But using one of the formulations with a higher boiling point, perhaps 76 C like Novec 7200, would have nearly identical cooling performance without elevated pressure. Right?
> 
> As an aside I am interested in using this stuff on some power electronics which generally have a much higher maximum temperature than PC components. In researching this post I noticed that pure isopropyl alcohol is non-conductive, has a boiling point low enough that power electronics would be fine in it and is cheap. Too bad its flammable, but I only need a few tablespoons in my application, so I might try it anyways. http://www.panachem.com/msds/iso_propyl_alcohol_IPA.pdf


This is inevitably true; however it is still the most efficient way to remove heat. Note how I say most efficient and not the most powerful. LN2 (or Helium-4 if you're NASA) are the most powerful. Phase change is the most powerful one that can be sustained (unless you're NASA). Where evap chambers with fluids like Novec 7000 shine is it takes remarkably little energy to remove the heat. Realistically you could hold around a 40c +/- 5c temperature with using maybe a couple dozen watts of energy.

*
The exact same concept applies to any coolant medium, just with less explosive worst case scenarios. People have used TEC chillers and their pumps fail, the result is the tubes melt/deform and water sprays into their rigs. If your pump fails with a liquid loop the CPU fails and goes into thermal shutdown. Same with air cooling. The answer to prevent this is simple really, maintain high enough thermal dissipation.

Lets put this into a hypothetical. You could calculate your computers peak TDP from all the critical components, but that ignores the VRMS, RAm, etc. on the mobo and other devices. For this purpose I'm going to use the rated wattage on the PSU, because realistically your computer will never generate more wattage of heat than your PSU can supply. Lets say 800watts. If your cooling medium can only remove 500watts at the required delta temperature we're going to achieve your scenario. The rig will remove 5/8 of the required heat, the 3/8 will remain. The result is the internal chamber continually increases until it goes boom, or much more likely simply ruptures and spills as honestly the chamber is much more likely to rupture and spray the fluid than it is to go boom. It's not a bomb, it's a pressure vessel. Unless you have some kind of unholy pressure it's simply going to split at the weakest point and the pressure will take the path of least resistance and spray out.

I digress, back to my point: simply have a powerful enough cooling system. You would likely not go with air cooling, as it's not powerful enough. Watercooling in some way shape or form would probably be the most efficient way to remove large amounts of heat. If your unit generates 800watts of heat peak and your cooling system removes at least 800watts while keeping the coolant temp below 40c you aren't going to get those worst case scenario. For this bomb cooler scenario to work you more or less need a constant increase in pressure. To achieve that constant increase you need to generate more heat than you remove. Long story short, be sure to do your homework and remove at least as much heat as you're generating whilst keeping the internal condenser temps below 40c and won't have problems.

Now I'm sure the next point is even without a runaway pressure increase it will still be a pressure vessel and could fail. Yeah, that's true, but if you're vessel is going to rupture without a runaway pressure increase it's more than likely not going to go boom. If it fails at those lowish pressures it will almost certainly go "psst" rupture at a seam, spraying the fluid out the failure point. (much like it would most likely do in the runaway scenario. You could also avoid evap all together and pump the fluid through a radiator to cool it directly, and use a fan to force it over the heatsink. This would keep /most/ of the coolant from evaping, removing the stress on the condenser.

*

TL;DR Those potential hazards can be easily avoided if you set up your rig properly.

-Z


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## RnRollie

Why using Novec 7000 vs 7200? Besides having a few (minor) properties differences, maybe 7000 is a LOT cheaper to produce than 7200 ?

Novec's relative safe compared to other solutions outthere.
The number of liquids (at room temp) that are electrically non-conductive is very limited. Some dont have the right properties. Some are jsut difficult to work with. And some are potentially very dangerous. After the liquids, it comes down to gasses.
Novec's is engineered to be used "at room temp" so to speak; without too much complex and harder to achieve/controlled conditions.
Liquid butane or propane or.. iso-propanol need much more stringent conditions (not to mention - needing a way to keep it liquid)... a room that fills up with butane or IPA gas because of a leak is a lot more dangerous as Novec spilling out









Oh, and forget about the "pure" ones; in general whenever there is the minor contamination, the non-conductivity goes out the door

just $0.02









have you read technogiants adventures in liquid gas cooling ?
http://www.overclock.net/t/1346823/subambient-full-submersion-phase-change-cooled-pc/0_50


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## KarathKasun

Going to necro this thread again.

What about using a sealed Novec loop. Use copper for the piping, A/C (pumped phase change) rated heat exchangers, and solid copper CPU blocks. Passive phase change cooling system, and you only need a quart or less of the fluid, including the portion used for testing.


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## Xiniceler

Quote:


> Originally Posted by *RnRollie*
> 
> The number of liquids (at room temp) that are electrically non-conductive is very limited.


Is 1,1-Dichloro-1-fluoroethane (R-141b, HCFC-141b) among that liquids? Its boiling point is at 32C which is quite close to that of Novec 7000. However I haven't found whether it is electrically conductive nor how it reacts with common materials PC components are made from. Does somebody have such information? Have somebody tried using it for 2-phase submersive PC cooling?


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