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LIQUID SUBMERSION - a few helpful learned facts.

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  • Heatsinks
  • Overclocking
Last response: in Overclocking
October 29, 2006 10:47:37 PM

I completely submerged a Asus P5N32SLI w/Pent D Processor, Dual 7800gt Vid Cards, 4MB Corsair XMS Ram in Light Pure Silicone Oil. The oil was recirculated through a fan cooled radiator.
Did it work? Yes and No.
The good: Electrically Perfect Operation, Immediate Booting to windows, Great Overall Cooling. Looked Bitch'n.
The bad: Regardless of the circulation and Overall Fantastic Cooling,,, I discovered a small issue never talked about in the COOKING OIL, AND VARIOUS OTHER Submerged computer projects. This small item basically prevents liquid submersion from being viable with all of the experiments/projects I have seen.


Any (ANY!!!!!) practical liquid INCLUDING DIONIZED WATER. Silicones, PTFE, Glycols, etc, through capillary action, surface tension effects, etc. will always flow into the tiny spaces, pins, etc. in the board and system components and will NOT circulate away rapidly enough, regardless of flow rates, and will create tiny spots of INSULATED, NOT COOLED, areas that will cause localized overheating on your system components. This took awhile to determine why my processor would overheat when the surface of it and surrounding areas were 70F but the internal temps would ramp to 200F.

Solutions:
1. Supercooling- Unless you want to use Liquid Nitrogen or an equivalent to supercool the liquid to about 0F throughout the bath, you will not get the heat to dissipitate away from these areas faster then air can. If interested I can go through the physics calculations with someone who is VERY interested. The waste of energy/electricity to run a strong compressor or using compressed N2 or other defeats the purposes of going with liquid submersion to begin with.
2. Sealing all of the tiny spaces into the boards connection pins, and all of the associated system components. Good luck, you must use a dielectric, themally conductive material, and even if fully successful, you know have locked in the air that would normally circulate out of those spaces as it heats and expands. Sealed air is still an insulator. BAD IDEA.
3 Submersion of only the back side of the board. Sealing all of the small spaces through the motherboard with a thermally conductive, Dielectric sealant. This was my original plan and it works better overall then straight air cooling and water blocks. Unfortunately, it is time consuming and costs a few bucks to custom and thoroughly seal the back side of the board from the front compared to the amount of cooling you gain. I'ld really only recommend this to someone who really has the time and money and really is obsessed with jacking that extra few mhz from their system.

FYI: I am a chemist & chemical engineer. I have my own fab. shop and hav e lots of spare rare materials to work with.
I'm writing this general note for those who are looking to take on this fun project to let them know of an inherent flaw (I learned) in Liquid Submersion. I wrote this quickly so please don't bash for spelling errors, etc. I just thought I would contribute to those who are nice enough to contribute themselves.

More about : liquid submersion helpful learned facts

October 30, 2006 1:41:27 AM

I have heard of pplz doin this with double distilled H2O, and a fan to circulate the water around the submersed MB.

Also I have heard of pplz cooling the liquid with water cooling. ie the water is pumped out of your box and though a rad and back into the box again. The pump's inlet was placed over the CPU and the CPU did not have a HSF it was just exposed bare.
October 30, 2006 2:26:26 AM

I have seen some instances where people have used a liquid developed by 3M, called Flourinert. It stays liquid at very cold temperatures, is not electrically conductive, and best of all, is very very expensive (~$500USD per gallon, don't flame me if i wrong :o  ). There was a site i saw that did a review using it as a coolant. There was a chamber of liquid nitrogen, which acted as a heat exchanger cause a pipe carrying the flourinert was run through it. The liquid was deposited into another chamber, which was filled half full of flourinert and the motherboard/ cpu and stuff was fully submerged. I will post again if i find that site.
Related resources
October 30, 2006 3:03:49 AM

Sorry if I missed it in the original post but, did everything come out undamaged? I remember reading a few times when the solution gains a few ions and starts conducting, ruining CPUs/Mobos and so on...
October 30, 2006 3:59:06 AM

This may be a dumb idea but if I were you I'd give it a shot.

I imagine that you submerged the motherboard horizontally flat which I can see causing the problem you mentioned.

Just to convince myself that it doesn't work, I'd try submerging the motherboard vertically thus gaining the help of gravity to move the liquid in those tiny areas that normal flow doesn't affect. Of course this will necessitate a differently shaped container or a greater amount of liquid.

It's a long shot but I don't give up easily.

HTH.
October 30, 2006 4:26:23 AM

4VOC answers and comments:

Flourinert and Transformer Quality Pure Silicone (both used for submerging industrial electrical components) are similar in viscosity, temperature behavior, etc. The silicone is however a bit cheaper and is not likely to generate any HF (hydroflouric acid) if it gets overheated. (ie by getting into a space it cannot escape from, an electrical failure, arc, etc.)

The board and all components all came out completely fine and perfectectly functional. Silicone (when pure) is COMPLETELY inert (inert means it cannot and does not react with any of the pastics, ceramics, metals, etc.) The only thing silicone can do is absorb very slightly into any silicone o-rings (sometimes on liquid pumps) but,, it does not destroy or attack them, it just will slightly swell them a bit (the unreactive chain lengths of the silicone oil and the O-RINGS are drastically different and therefore do not chemically effect each other). This actually can be a good thing here because it helped the seals. A bit of DI (deionized water) and light citrus degreaser soak followed by a rinse with 70% isopropyl and air dry cleaned off the silicone residue pretty easily and thoroughly.

I did Recycle the Liquid using two pumps and two radiators (For recirculating and thorough cooling overkill) Keeping the liquid cool was not a problem at all nor was keeping the outside of the components cool. The problem was you can't circulate the tiny spaces behind the pins of the CPU and other like components and THAT"S where there is a problem with submersion and that's why it works great for TRANSFORMERS and LARGE electrical devices but really that practical for microchips. Flourinert, Light Silicone, DI Water are all two viscous too move thoroughly in the TINY spaces around the cpu, etc. That's where the heat is retained and that is where you get the problem.

I've read numerous posts on the various liquid cooled systems.
-DI water is just too short term and will , ALWAYS will pick up dust, particles etc. and no longer be pure after a short period and will cause issues, Unless you make it in a class 10 chip room, its a waste of time.
-Flourinert and Silicone act the same and are Almost interchangeable and cause the micro localized hot spots that I have discussed. Cooling with liquid nitrogen is not practical except for a quick fun but VERY short experiment.
-Cooking oil is just silly as it breaks down, allows for bacterial growth, smells, and will slowely react with some of the bonding materials, etc. Additionally, it does not prevent the same problem of localized heat spots behind the chips.

Another thing I did not mention, I even put a SEPARATE WATER BLOCK with isolated coolant flow to the CPU and resubmersed the board in circulated and cooled silicone. This had little or no change. I did several other quick experiments and concluded that with any liquid access to behind the chips it will build up heat in these tiny spots which will effect the chips performance negatively.
October 30, 2006 11:57:04 AM

a simple solution would be to look for a mobo that has drilled holes right under the CPU (inside the socket). If my memory serves me well, there used to be some like these at one time. Not anymore?
October 30, 2006 9:42:14 PM

A Few Answers:
1. Refrigerator: Yes you can do this but, without a pump, and either metal walls or a radiator, you will just have the same problem (albeit less). The liquid will not move away quick enough from the processor and chips.

NOTE: The goal here was not to SEE if it could be Done but to See if it could be done easily, cheaply, in a clean setup that does not require MORE energy but LESS energy to run. Unfortunately, a refrigerator or compressor (which is what's in a refrigerator) uses too much electicity and defeats the purpose. The theory is sound and tested to be good here. The DOD, the EVERY ELECTRICAL TRANSFORMER YOU SEE and many other companies use this technology all the time. The problem is to do it cost effectively and practically with the way PC chips are made leads to this problem with tiny localized insulation spots behind the chips.

2. There was no and would be no moisture issues as long as you have a reservoir or case setup that allows any condensation to accumulate away from the process.

3. I tried this setup horizontally, vertically ATX Style and ATX 90deg. No difference in either of these setups. All had great overall cooling but tiny hotspots formed behind the chips. This all supports my conclusion of the problem.

4. The Socket 775 has not openings behind the chip and is litterally saturated with tiny pins. There would be no way to realistically vent this spot. Therefore, there would be no realistic way to get flow back there unless Intel redesigned the socket or I custom fabbed a socket setup which would.... umm take alot of time and would be very likely to open up a another set of issues. Venting the board itself would not help much as redesigning an entire board to remove these tiny spaces would kinda defeat the purpose of this project. If someone wanted to grant me a couple mil. the patent rights and a circuits mfg shop I think I could do this easy enough. :) 


4. I hope I have some pics. Camera is with one of my work crews so I'll try to check. I was originally planning on writing an article for my friends online magazine on the finished product with a how to guide and clocking Specs. As I did not forsee this issue, I never finished the fancy dressed up product and I stopped documenting the test rigs. I already have taken out the board and put it in an office computer while I wait for my new gaming board and core2 chip to arrive.
Don't really like the ASUS P5N32 board as it is junk and the company released about 20 versions of it under the same name and false advertised and covered it's problems. IE: Their Website Stated it was CORE2 Compatable up until a month ago well after they released the SE version (unnamed originally "SE") without telling customers their was a difference and without accepting returns or upgrades to all that bought the original versions thinking they could run Core2. The PentD series is already outdated by the Core2 and uses WAY TOO MUCH Power. If you try to run a Pent D and with SLI, Forget about running stable with a 500-550W power supply. It WILL run, but you will have voltage issues under stress.
October 30, 2006 10:08:22 PM

Forgive me if I'm wrong here, but working from memory, isn't Silicone Oil a terribly poor thermal conductor?
October 30, 2006 10:20:26 PM

I beleive water is also a terrible thermal conductor...
but water can abosrb heat... to get water cooling to work best you have to get each water molicue to hit the heated side of a water block(making the storm jet impingment so good).

but not sure about Silicone oil.

Please correct me if i'm wrong...
October 30, 2006 10:30:32 PM

Someone I know of tried a similar thing in the past, but although with a fairly disposable machine. His solution (although undoubtedly not the first to do it) was similar to prepping for a peltier. Basically he siliconed the backside of his north/south bridge, cpu, (v/g)pu, agp/pci slots and ram, and shoved some dieelectric grease down the cpu socket pin holes. Anyways, it worked, but being a much older machine (p3-800) it is probably much more leniant than your machine. Oh, he used thin over the counter engine oil.
October 30, 2006 10:51:16 PM

The thermal conductivity of DI water is roughly 3-6x better then Light Silicone oil, Vegetable/cooking Oils, or Ethylene Glycol (coolant in water block systems and cars), PTFE ... 3x6 roughly based upon mixture (ie w/water). The viscosity (in laymans terms) is the measurement of how well it flows. I used a very low viscosity liquid so it would flow like water.

Now 3-6x worse then water seems bad, but that is why you use active forced circulation. Ie. your water block systems use a pump and 300gph flow per chipset. (roughly) This more then makes up for this inadequacy.
Additionally, I tried DI water, vs. pure silicone, vs. ethylene glycol/water mix through a seperate water block with and without silicone submersion.

Without Any Submersion: All the liquids more then adequately cooled the Processor steadily at about 35-37deg. C.

With Submersion: No water block: 90deg-100plus C and rising: Shutoff system.

With Submersion & water block: 90-100plus C and rising: Shutoff System.

With All the Submersion scenarios, The overall temperature of the Surface of the Chips was fantastic and the heat was pulled away and cooled by the radiator. BUT... In all cases of Submersion the internal Cores of the chips would build up slowely getting hotter and hotter while the exposed surface would stay very cool. As it was easy to see that the heat was being pulled off the surface of the chips (where a water block or cooling block would sit) The only conclusion was that the liquid was not able to circulate out from behind the chips (which in retrospect makes sense as these spaces are very very tiny and will and would always pull in fluid through capillary action/surface tension and not willingly release these fluids). Air However will circulate in these areas and in fact expand out and release from these areas at an increased rate as the area heats up.
October 30, 2006 11:01:37 PM

I'm sorry if this has been mentioned, but maybe try pointing a few powerheads/aquarium pumps towards components that overheat and maybe you can force some of the liquid to circulate around these insulated spots? or maybe having a tiny space between the motherboard and socket with a pump pointed towards it to push the fluid inbetween the pins?(if that would work at all, it might have been easier with older sockets like s478)

Just my $0.02
October 30, 2006 11:01:55 PM

There are basically two things to think about with heat: specific heat capacity (the amount of energy needed to raise the temperature 1 degree) and heat conductivity....

Metals (in general) have great heat conductivity but almost no heat capacity,
water on the other hand has great (really really high) heat capacity but bad heat conductivity.

This means that water can absorb alot of heat (but it also stays warm) and if you also circulate the water you can cool it off somewhere else.

From the top of my head, I think that water has one of the highest heat capacities of any liquid (seems ammonia is a little better according to wikipedia ;)  ).

For heat conductivity, diamond wins the race but an order of magnitude... I've always wanted to grow a diamond heatsink. :) 
October 30, 2006 11:33:09 PM

Quote:
Any (ANY!!!!!) practical liquid INCLUDING DIONIZED WATER. Silicones, PTFE, Glycols, etc, through capillary action, surface tension effects, etc. will always flow into the tiny spaces, pins, etc. in the board and system components and will NOT circulate away rapidly enough, regardless of flow rates, and will create tiny spots of INSULATED, NOT COOLED, areas that will cause localized overheating on your system components. This took awhile to determine why my processor would overheat when the surface of it and surrounding areas were 70F but the internal temps would ramp to 200F


so here you are talking air bubbles right?
if so i could see how the that would cuase problems.

there would be, maybe thousonds of them.
October 30, 2006 11:59:42 PM

Sirheck, Not air bubbles. Go take a straw, put it in a glass of water and watch the water move up the straw above the water level, the less the diameter of the straw, the more it will move up. I'm trying to explain this the easiest way I can. I only tought chemistry one semester. :) 
The spaces fill with the liquid after a bit of run but are just TOO small for the liquid to move out of quickly enough. Go pop out your Socket 775 Chip and look how tight the spaces are between the pins behind the chip. This is also the case on the vid chips, ram, etc. Liquid goes in,,, liquid does not want to come out. The air bubbles (if any) disappear quick when the chips heat up, the air expands, bubbles away and the liquid fills in.

Nitro350Z, I did put the inlets of the pumps pointed right at the chips, I even tried not submerging, just spraying the chips. I had several radiators and 4 different pumps and countless configurations i laid out and swapped about to try to solve this,,, I spent a few 5am sessions at the shop obsessively trying to prove that this could be done easily. Oh Enrubi, and they do grow some pretty big synthetic diamonds now.... but... they're still pretty dam expensive.

Older Chips with less pins and that do not run so hot (like the Pent D series) would definately be easier. Putting dielectric grease is possible but, really wouldn't help very well unless you used a Potable dielectric /themally conductive plastic or ceramic (which are available now but this again would be extremely time consuming and add to the cost, plus with the imperciseness of this kind of molding in conjunction with the sensitive areas you are working, I really really would not attempt this with nice stuff unless you have a circuit board mfg facility.
October 31, 2006 12:03:04 AM

Quote:
Any (ANY!!!!!) practical liquid INCLUDING DIONIZED WATER. Silicones, PTFE, Glycols, etc, through capillary action, surface tension effects, etc. will always flow into the tiny spaces, pins, etc. in the board and system components and will NOT circulate away rapidly enough, regardless of flow rates, and will create tiny spots of INSULATED, NOT COOLED, areas that will cause localized overheating on your system components. This took awhile to determine why my processor would overheat when the surface of it and surrounding areas were 70F but the internal temps would ramp to 200F


so here you are talking air bubbles right?
if so i could see how the that would cuase problems.

there would be, maybe thousonds of them.

I think it's more about the fact that the speed with which a liquid moves in say a tube depends on the distance from the walls. The speed is the highest in the centre and very very low along the walls because of surface tension etc.

A high viscosity liquid (like an oil) flowing in a complex geometry will most probably form "dead zones" where there's next to no flow at all.

Air can be considered as a low viscosity fluid btw.


Growing synthetic diamond isnt that hard: 1 oven, 1-1.5% methane gas, the rest argon, perhaps a few tiny seed diamonds, time ;) 
October 31, 2006 12:11:21 AM

Quote:
Sirheck, Not air bubbles. Go take a straw, put it in a glass of water and watch the water move up the straw above the water level, the less the diameter of the straw, the more it will move up. I'm trying to explain this the easiest way I can. I only tought chemistry one semester.
The spaces fill with the liquid after a bit of run but are just TOO small for the liquid to move out of quickly enough. Go pop out your Socket 775 Chip and look how tight the spaces are between the pins behind the chip. This is also the case on the vid chips, ram, etc. Liquid goes in,,, liquid does not want to come out. The air bubbles (if any) disappear quick when the chips heat up, the air expands, bubbles away and the liquid fills in.


ok cool just wondering how you got all air out of the system.
i was thinking when air is heated it expands?
October 31, 2006 12:16:05 AM

aahh yes similar to bernoulli,s law. ok
October 31, 2006 12:28:15 AM

Fluoroinert, man it's been a while since I've heard that! We used it for cooling solid-state power frequency converters on my ship, the 60-400Hz converters that make power for our "delicate" systems. FC-72 to be exact. FC-72 has roughly the viscosity of water, but it evaporates immediately upon exposure to air so you'd have to have an air-tight seal or it'd be gone in a day. Another big problem with it is that at ~200C it will form hydrogen fluoride, so hot spots could be a big problem. Also, it's several hundred bucks a gallon (we get it for around 300-400 it changes). Interesting idea though, I've often thought of using it in a closed-loop water-cooling setup, but it really has a way of escaping closed-loop systems, and it's too damn expensive and I'm not about to defraud the government cuz it's not that much greater at heat transfer than H20.
October 31, 2006 12:39:00 AM

Oh, and a funny fact, if you drink FC-72 you piss it out almost instantly. Good times.
October 31, 2006 2:50:34 AM

This just goes to show why PCC (Phase Change Cooling) is the only pratical (but expensive) way to achieve super-cooled states. Remember, your not trying to 'put cool in', you have to transfer heat out. Simply 'dunking' something in a cool substance might cool it temporarily, but once the substance you're using reaches a certain state, you usually wind up 'heating up' the object you're trying to cool, no matter how much circulation you might have in a confined space. You need to have a radiator, or some form of heat exchange, to remove the excess heat from the substance. Otherwise the heat is simply recirculated into the system, and cooling drops off at a rate determined by the specific heat of the substance.

For maximum cooling, you need a substance with 3 requirents:

1. Low to Meduim Viscosity of coolant substance to surface area:
It's important to remember that any cooling has to reach ALL areas. If the substance has too high of a viscosity in comparison to the flow path, you will get 'dead zones' of little to no circulation, and therefore little to no cooling. This is dicttated by geometry, as well as the physical properties of both the coolant, and the object being cooled. A flat wide area will have very different needs than a crowded area with lots of irregular shapes in the flow path. The smaller and more irregular the flow path, the lower the viscosity needs to provide adequate heat exchange.

2.Defined circulation pathways:
Any cooling substance, whether liquid or gaseous, needs a well defined 'flow path' to ensure proper circulation and heat transferance in all the nessesary areas. Simply dumping something in a tank with a circulation pump does no good. Ideally, the flow should start at the hottest spot and flow past the lesser heat areas away until it is gathered and sent to the radiator/heat exchange. Once there, it is circulated to release it's heat, then it is re-introduced in to the cooling system.

3.Thermal exchange:
Thermal exchange is governed by the values of a substance in 3 different areas: specific heat (a measure of how many units of heat it takes to raise the substances temp/volume), thermal conductivity (how quickly/easily a substance absorbs or releases heat), and finally, latent heat (or vaporization)which measures the heat gained or released during a change of phase (from gas to liquid, liquid to solid, etc.). Heat tranferance is most efficiently accomplished by the phase change, since larger volumes of heat are absorbsd or released during phase changes. Phase changes can manipulated with the use of pressure. Low pressures lower the vaporization point (so you can boil or condense a substance at a lower temprature), while higher pressures raise the same (to absorb more heat by avoiding the 'boiling point', achieving 'super-saturation').

OK, now I can fully explain how it works;
1. High pressure/low temp. liquid is sent to the cooling area (evaporator). The liquid enters an 'expanded' area, where the expansion allows the liquid to 'boil' off into gas, and absorb lots of heat in the process.
2. The low-pressure/low temp. gas is sent to a compressor, where it is turned into a high pressure/ high-temp. gas.
3. The high pressure/high temp. gas is pumped into a radiator, where it is allowed to slowly expand (as it works its way through) and release its heat (through convection), returning to liquid form.
4. The low-preesure/ low temp. liquid is sent to a Condenser. The condenser re-pressurizes the liquid, which is then sent back to the evaporator.

With out some phase change, you can't get decent cooling in a small closed system.
October 31, 2006 4:44:50 AM

good overview and summary of what we've been talking about... but ...

If you read the original or follow up posts.... the overall submersion theory isn't a bad one and if done right transfers the heat away great...
the coolant was flowed directly to point of heat generation, and pulled away and recirculated to a radiator where it was cooled to ambient temperatures. even additional direct water blocks, pumps and radiators where added with no effect. it was extremely easy to keep the liquid cool, the case cool, the board cool, the surface of the chips cool.

What could not be cooled was the tiny spaces (in many cases less then the width of a hair) that cannot be practically circulated away.

one of my points i'm getting at is... if you DO want to waste money on a condenser unit and DO want to waste another 1000kw of electrical usage to run it so that you can drop your coolant down to any sub-ambient level and so you can jack an extra bit of mhz your STILL BETTER OFF using water blocks instead of submersion.

FYI, doing this would have defeated one of my goals. To make a practical way to create a quiet, low energy, cheaper way to provide above average cooling. Cheaper because a sealed case is cheaper then water blocks for the twin vid cards, CPU, RAM, North Bridge, South Bridge, and the circuits inbetween that begin to get hot when you start to seriously overclock the major components.

submersion still is bitch'n looking though. :) 
October 31, 2006 1:15:19 PM

Very interesting! 8)
October 31, 2006 2:19:34 PM

Maybe I missed it but what happens if it is submerged with the heatsink in place?
October 31, 2006 5:06:26 PM

4voc,
I'm not trying to undermine what your trying to accomplish. It's just a little more complicated. I was a Refrigeration specialist for over 10 yrs., both in the military and in the civilian arena. I have knowledge in convection, liquid, and Phase Change refrigeration systems. I also know both passive and active cooling, and try to keep up to date in Peltier systems (which ain't easy).

Liquid cooling is only viable/effective in large scale, fairly smooth areas. Believe it or not, most large malls use it. Thats what the fountain is for, it is the heat exchange to cool the water before it is pumped back the A/C system (though it is often supplemented with a secondary system). Only gases have the nessesarily low viscosity to properly cool a small irregularly shaped object, like a mobo.

Listen, I'm not trying to negate what you're attempting. I'm simply passing on information to help explain why it's not working as well as you thought it might. I've even tried to supply some additional info that you can consider and/or research at your leisure, if you decide to try again in the future. Heck, you could be the next genius to come up with a truly viable, efficent solution to cooling and retire rich and famous. It's not entirely out of the realm of possibility.. :D 
October 31, 2006 6:10:36 PM

Rripperr, no worries man. I agree with your comments. I want to either/help people from wasting time doing something that will waste them time and be frustrating... or find possible solutions as I can't seem to find one yet that is feasable. I get frustrated sometimes on these types of post 'cause you get alot of Two Cents which are a. completely wrong and often damaging to the person if they follow that advice. b. just repeat of something that has already been said.
You are right that submersion is used all the time in industry and note that the liquid I used is a common transformer coolant (one of the replacements used for PCBs!!!)
You are also correct that if a PC board and it's Processor and other Chips only had large smooth surfaces, this would be a very easy project and conversion. The problem that I can't overcome at this time is that... and the problem that I want others to understand before they waste their time and money on is.... The board and it's chips aren't purely generating heat on their surfaces but also behind and around them in the tiny spaces and that liquids will insulate these areas not cool them even when you go overboard with recirculation and cooling. Keep in mind that if you cool and of the liquids we have discussed, say to zero F, they will become more viscous and at least on a micron-local level move much less if any from these spaces. Thereby you'll have even less heat transfer to these areas and a greater temperature spread across your chip and I would theorize that you could even crack your chips from the temperature changes. IE, but ice in a hot glass or a hot glass in the freezer, Or even spray your CPU Water block with canned air (if it has the typical plastic cover) while it's running or just been turned off.
Note to the wary: if you do use a chilled coolant for your water blocks, make sure your pump starts and stops after the pc powers up and down and preferably use completely metal blocks with no covers. You will shatter the plastics.

rcs2749: heatsinks where used, and tried without. The heatsinks work better in the submersion as they extend out the heat into the liquids and create more contact area. But, overall I never had a problem keeping the surfaces of the chips cool (you can tell by using a temp.gun and/or thermocouple probes) My company and shop has alot of cool test equipment so I could use the temperature probes to see where the heat was in most cases and adjust accordingly)
October 31, 2006 7:50:23 PM

It seems to me the matter that is bothering you the most is the micro-"deadzone" pockets where the fluid itself is not circulating, yet these pockets are typically not the primary surface for disipating heat, although they do require some disipation.

My thought is, even without any movement in the fluid, the sheer volume and contact areas should be able to the required transfer heat much like a solid, and overcome its lower conductivity. Even if you were to have deadzones between pins or circuit boards and the chips themselves, the chips should be able to conduct (via their electrical contacts or otherwise) the excess heat through the area that is normally exposed to air, and far better when submerged.

I still think there is another problem at hand, perhaps its minutely shorting out.

Edit: Oh, and btw, the person I spoke about before, he is using synthetic motor oil in his P3-800(linux samba/router).
October 31, 2006 7:51:23 PM

A truly unusual cooling method that would be viable (if somewhat difficult) would be to hermitcally seal the case, and pump 'moist' cool air through it. Moist air, around 40-60% humidity, can actually absorb a fantastic amount of heat fairly quickly. The only problem (besides accelerated oxidation in ferrous and copper components) is the evaporator usually condenses the water out of the air, which means you have to find some way to add it back in before it enters the case again (with out adding heat). It's something I've been thinking about off and on for the last 3 years.

Unfortunately, I haven't been able to arrive at a convenient solution. It woud probably require something just sightly smaller than a window unit A/C. Like maybe one of those small dorm 'fridges. Hmmm.. Duct the air in and out. Air goes in the top (near the 'freezer' section), take the air out near the bottom. Keep a 'pan' of water in to raise humidity levels.. Hmmm.. I'll have to think about this.
October 31, 2006 8:04:58 PM

Rripper, a much easier method would be to take a lead from heavy electronics back in the late 70's/early 80s in submersibles(radar/sonar, etc) where they would make precision aluminum blocks that would mount between the component and their chasis. The inside of the chasis was ribbed for more contact area with the air inside. The chasis would then disipate all the heat.

Its kinda like the Zalman TNN systems, only using solid blocks to connect the hotspots to the heat disipating chasis, and they were sealed off.

That would be similar to your sealed off case, and without the moisture problems. I do not know what kind of "air" they had inside, but I'ld imagine it was just normal filtered air.
October 31, 2006 9:42:34 PM

Rripperr: The misting idea is a good idea in that the evaporation of the water actually pulls heat out of air. This would be like a swamp cooler or misting tower which you should be familiar with. Bad news is. Water would never be a good option and using light coolants would shortly cause the same problems I had because it would condense and drip down behind the boards.

Praeses: I've been trying a bit of better block designing for heat dissipitation including different gas or water flows through them and arrangements to pull heat from the hot spots, I'm just a bit limited on time because I'm supposed to be running a company not playing. :)  I have a few other ideas that I'll try soon so I'll keep you posted. Oh, and those finned Al blocks are called Heatsinks... which are alll over the boards already. :) 
Praeses #2: Pulling heat through circuits, to then dissipitate is heating the cooled spots. As electrically everything was better then normal with this board (p5n32sli boards, first editions, where notoriously voltage flawed) and I could see the heat spots behind the chips. I think that primary or not, liquid behind the chips doesn't fly. My surface temps of the chips where steady at just above ambient, but the chip cores where ramping like a skateboarder on chrystal. Therefore, again, I'm pretty confident that these tiny spaces are the problem. In fact, another bit of evidence that I just thought of this moment is a phenomenon I've seen alot of , peoples OC'd boards with adequate surface cooling. I've noticed alot of boards get slight heat warping behind the processor socket when OC'd even when the chip itself is cooled with a highend waterblock. Normally these spots would not be a big deal, but when OC'ing they do become a big deal. A processor has alot of tiny molecule sized circuits in it, and if you have to transfer all the heat from one side to the other to keep it cool...your adding to the problem not fixing it as I think I've shown. Which really kinda sucks because, the liquid submersion fixes this problem for most of the board and it's components, just not some of the most critical spots where it makes it worse.
October 31, 2006 9:53:50 PM

I just pulled a p3 2000mhz chip off an old board. Night and day. Its 4 times the size with 1/8 the cooling surface for the chip. The spaces are much larger and the pins are located mostly far away from the part of the chip that generates the most heat. Additionally, it's using (guestimate 'cause it's not worth looking up) about 1/10 the KW (without OC'n)in a space that's 4times larger. AND. The pins extend THROUGH the motherboard. They don't on most the newer boards, the processor pins are in a seperate socket, which is then connected through seperate pins into the board. Night and Day.
November 1, 2006 1:00:10 AM

Do you think you would have had the same problem if you had tried with a socket 478 based board ?

or about the same question, do you think the pinless/holeless socket 775 exacerbates the problem ?
November 1, 2006 1:35:40 AM

of course you ask that after I've left my office where I have a couple socket 478s on Dell boards...

So I pulled a few picks up off yahoo and it looks like they show it being in front of the board not integrated into the board. So, I did see a few ways it is setup in the pics but some look somewhat similar albeit a little less crowded then the 775 I used. I would assume though that you may have the same problem, BUT that it would be less, Keep in mind. The PENTIUM D Chips seem to run ALOT hotter and USE ALOT more energy then the chips I have in my P4-3000mhz socket 478 Dells.

So, just making an educated guess. Same problem would happen, but as it is using less electricity in the same amount of space with less crowding and less heat generation, it may be still a problem but not nearly as bad. I don't think these couple generation old Dell units can unlock and overclock the Processors easily, but I'm not sure. And honestly, they're good enough for work use so It's not worth trying it for me right now.


FYI, IF there are any technically savy readers with free time and trustworthy (you would have to undergo a security and drug test, and you are located in the Los Angeles Area I would consider letting you repeat/modify/update/fix/make better this project with my materials and document it for publishing to an online site or two.
November 1, 2006 5:13:03 AM

You know, I checked out some pics too, and there may not be an easy solution to cooling underneath the 478 and newer CPUs. The seal and tolerances required for them to operate with the newer connection brackets nessesitates that the zone directly under the chips will be a "dead zone". Ventilating properly would require drilling holes THROUGH the mobo (without hitting any 'traces or xsistors)under the CPUs. Even then, depending on how much PCB you removed, it still might not be enough. :evil: 
November 1, 2006 5:45:19 AM

Well, you could try turning the case into one large submersible pump. You could use a siphon at the top, sealed with silicone, along with a vaccuum apparatus to suck the fluid out, which could then go to some sort of radiator, then back into the case. The "pump" would effectively be cooling itself, and the fluid moving inside the case would help dissipate any hot spots.

Just a thought.
November 1, 2006 7:08:51 AM

hmm, you don't seem to read very well. there was a reason why I only tought college chem for one semester... at least i can fire my employees now.

Dude, read at least a few of the posts before you make a suggestion... .... a suggestion to do something was done from the start and discussed in multiple posts.

rripperr, I think, if you could do it successfully, it possibly could help... if someone wants to play with my setup rigs, they're more then welcome, I've got another idea for a new setup with some new hi-tech materials that I've got samples coming in on. This would be a bit easier then complete submersion and if it works would be marketable. I'll be trying it out within a few weeks on my core2/intel975x setup that I'll have tomorrow.
November 1, 2006 9:16:58 AM

Hi,

I think your are asking too much from the current chips designs, they tend to dissipate the heat trough the top metal surface of the heat spreader and not from the bottom, which is thermicaliy insulated, the hot spots revealed by your infrared probe are heat build up inside materials with low thermical conductivity and not on theirs surfaces such as the inside the PCB, chip socket, etc.
The only way to avoid that is to change the chips design and there are some ideas such as:
http://www.zurich.ibm.com/news/06/cooling.html
November 1, 2006 4:24:42 PM

Nice Link Mad guru. Thanks, I did find another few "future" materials used by a couple of my aerospace customers that may help me address the back of the chip a bit better. As far as the front goes though, this is a pretty article. I'll take a stab of making a slightly less intense version version of this.

And yes, I think I am asking too much out of the current chip/socket/mb design. :)  but, i solve technical problems for a living so... :)  doesn't mean I won't keep trying ... as long as i'm interested. or someones paying me...
November 3, 2006 5:40:40 AM

jesus, just forget about submerging your computer, and just water cool it.
I could never imagine doing that, its just to messy, with little or no gain over a normal water cooling setup.
November 3, 2006 4:32:26 PM

you called?? :twisted:

Of course, and let's keep bush as president, stick with a petroleum based economy, develop our parks into stripmalls, ......

hmm. didn't you learn to oc your p805 from some innovative person smart enough to look into it's mfg quirks, see possibility and test out it's oc abilities?

jesus has nothing to do with innovation... go shop at the mall and stay off the tech forums......
November 3, 2006 5:31:15 PM

In regards to using fluorinert, 3M will try to dissuade you from buying fluorinert (they were the original manufacturer). They do produce other perfluorinate hydrocarbons (excuse the spelling) which have much lower gel temperatures and would therefore wouldn't thicken up till much lower temps. These compounds are also much cheaper than fluorinert, with all of the good properties preserved.
November 4, 2006 12:58:27 AM

ooooohhhhhhh.......... sh*t
So tell me what ARE your "GOALS" in this project?
Tell me your GOALS and I tell you if they have any real world ADVANTAGE

Never mind I guess, this project was just for some weekend fun
January 11, 2007 1:49:58 AM

I'm new to these forums here, as I was referred from other forums to find the thread author and his submersion warnings.

I had a question: since the whole case that will be submerged is not very large, does it make sense to:

a.) fill with some appropriate liquid (I was leaning towards something that I don't have to replace/refill every few months, i.e. not oils).
b.) fit fans that direct flow in some direction
- have some directional motion that circles the cool liquid around the case, and have the warmed liquid return to the original spot (** like a loop in water cooling).
c.) have some sort of cooling system, like 500W Peltiers, to cool the liquid.

That way, your liquid keeps circulating, and the probability that molecules remain in one single location is reduced greatly.

Does this work? Or is the official conclusion (Shout to the world) that submersion is not meant for computers?
January 11, 2007 6:36:00 AM

The biggest difficulty with liquid submesrion is not that it doesn't work, it's that current hardware isn't geared towards it: flowing the liquid about is, as we could see, not always efficient, due to some liquid being sometimes trapped in a hot place anyway, and reaching boiling point. Were motherboards and such created for submesrion, with well sealed interstices and smooth surface, then submersion would indeed be successful; but right now, not only does it require exotic products to work on a long term, it requires very delicate hardware handling - and some boards are better at it than others.
January 12, 2007 8:26:36 PM

Quote:
Hi,

I think your are asking too much from the current chips designs, they tend to dissipate the heat trough the top metal surface of the heat spreader and not from the bottom, which is thermicaliy insulated, the hot spots revealed by your infrared probe are heat build up inside materials with low thermical conductivity and not on theirs surfaces such as the inside the PCB, chip socket, etc.
The only way to avoid that is to change the chips design and there are some ideas such as:
http://www.zurich.ibm.com/news/06/cooling.html


Just a thought to trying to cool and get coolant movement under the bottom side of the cpu. It would be interesting if the cpu's "prongs" were like 2or3 inches long and it was suspended above the socket. . Then coolant or whatever your using could move under it all around it and even between the prongs

This was just a thought and I have no expertise in any aspect of what your trying to accomplish.
January 12, 2007 8:59:12 PM

Howdy,

Fascinating post. Just throwing stuff out, but could possibly adding something that vibrates the MB shake loose the pockets of stuck oil and help to move it along. Or some high rate of bubbles, something to collide with the particles. OK, I know your talking the width of a hair and that air bubbles are bad, but how cool would it be to have those deep sea divers and treasure chests that blow bubbles in your computer cases!

I just write code, so I have no idea if any of this makes any sense. Yall are on a level I’m not even going to imagine to be at.

Keep up the posts…very cool stuff indeed.

Doody
May 3, 2010 3:48:08 AM

If your rich you can do this and have it work nicely, get a few gallons of 3Ms phase changing coolant Perfluorohexane (prohibitively expensive for those without at least $20,000 burning a hole in your pocket). Modify your motherboard so the capacitors are covered with water tight shrink wrap if they are electrolytic.
Create an air tight case that has a place to suck air out of and a place at the bottom to pump the coolant back in and I/O ports and put your computer and the Perfluorohexane into that sealing it. attach a pump and condenser and cooling track to that and start up your computer.
It will probably pull quite a bit of energy and make sure to test the condenser and cooling system for leaks first as that stuff is slightly toxic. Overclock your new Tesla Super Micro that cost you a grand total of $15000 to buy and set up and about $400 a month to run and program a new game for it and play like a king. Dont forget to buy the fiber optics throughput and have your super frag fest with a ping of 0-2.
better yet use it for grafix rendering and rent it out or use it as your grafic design platform. or SL programing and scripting platform.
???
PROFIT!!!!
a b K Overclocking
May 3, 2010 12:55:08 PM

DO NOT BRING UP DEAD THREADS!
a b K Overclocking
May 3, 2010 2:23:02 PM

This topic has been closed by Maziar