fully submerged cooling

oil bath computer
Markus Leonhardt has taken the shortest route possible to liquid cooling.

  1. throw motherboard in fish tank

  2. cover in vegetable oil

  3. there is no step 3

Markus has been using this system for over a year. it is quiet and is cooled by the still functional fans circulating the oil. he has swapped components and even successfully used pulled hardware in other pcs. the pages are in the process of being translated to english, but the english forum is already up with links to other projects. I’ve got some extra hardware and fish tanks are cheap, so I’ll give this a try some time. I doubt my roommate will feel this is an improvement over my plan of just nailing the motherboards to the wall.

82 thoughts on “fully submerged cooling

  1. Pure genius! I’d like to see more people try this and report the temperatures they are getting, should just be over room temperature, which is great, would be a pain plugging and unpluggin those USB though.

  2. Is the type of oil important? Does it smell? I’ve read that harddrives shouldn’t be submerged, but can everything else (that would benefit of course)? Anyone have other links to this sort of project?

  3. This issue have been discussed many time in Spanish wireless communities, actually, is being used on Wi-fi links and linux hot spots on roofs to avoid rust, and humid condensation. It’s really a good solution for not very hot processors, and you must consider oil, being degraded to grease (wich in fact can bring problems)… (sorry for my lack of practice in english ;-))

  4. Well I was looking around and people have the same problems. They are looking for some good non corosive and non conductive oils and couldnt get anything that wasnt perfect for under $150 a gallon. So my thought is take one of the electric oil space heaters and drain the oil into the fish tank. That oil is non corrosive and conductive.

  5. were you angry at your motherboard so you had to nail it to the wall?

    ive seen this sort of project been done before, but with a much more expensive form of oil, this is a great improvement.

    i guess hardware with motors is a bit out of the question, and certainly no passing 110/230v through it.

    This also would look pretty spiffy with some ink dye, and some cold cathodes, some awesome case mod

  6. I did this about three years ago, but I left it in the garage and it started growing things… One small problem with an organic based liquid you are constantantly heating to a little over room temp….

  7. Even if there is degradation of the oil, a three thousand mile oil change (or like once a month or so) should cover that issue pretty good. If you did this as a case mod, add the pretty blue and green lights, the glass fish, bubbles and some other fish toys, put a section at the top for your “dry” components (CD, Drives, USB connectors). It would rock…

    I wonder how long the fans last in the oil environment. It seems to me they are always kicking the bucket faster than you would want anyway.

  8. This was done roughly 6 years ago, someone posted a web page of his computer components put inside a cooler, then filled with mineral oil. This was, of course, older technology, so the cooling needs were less, but he even got into submerging A/C coils into the coil to make it cooler. I think someone suggested to just move the oil around, you didn’t need to “cool” it.

  9. I concept i googled and found :


    I’m thinking of trying this out, only thing tho I’m probably gonna be getting a couple of USB extension cables so that I don’t to dip my hand in the idle rot-brewing temperatured orangic material.

    Also, if I cant get ‘mineral oil’ I’ll probably just use vegtable oil with loads of disinfectant mixed in and some sort of emulsuphire(sp?)

  10. I’ve seen this sort of thing before when looking at cooling a power supply for a tesla coil, someone had dunked a motherboard in hydraulic oil.The thing to note is that it is only a low spec processor, you would need some sort of oil cooler and a pump to run anything faster although it is possible. As for the comment about not running 110 or 240 through it, 11000 to 415 3 phase voltage transformers (and possibly larger)are oil cooled so your psu aint going to be a problem.

  11. I would not suggest using food-grade oils, and go with either petrolium oil or mineral oils. Food grade oils have the tendancy to rot, while petrolium and mineral oils are more stable against rotting.

    This is an interesting idea, I may even go as far as to suggest active cooling in combination with the oil. Keeping the oil cool will keep electrical conductivity low, and with active cooling and oil submersion you do not have to worry about condensation.

    I would also make one potential change, and that is to seal all contact points. Enough oil getting between a loose connection would lead to a no contact situation.

  12. This is not the first time. I check out Ars Technica (http://www.arstechnica.com) frequently, and a few years ago (note _years_) when I was going on a cooling binge, I read about a guy who took this a step further.

    he submerged everything, except drives, into a custom tank made of closed cell foam, and placed the evaporating coil of an air conditioner in the minneral oil, above the hardware. needless to say, it was cold (at freezing at points). he messed it up by leaving for work. a pertion of the evaporator coil became airborne, water condensed on it, and contaminated the minneral oil. the result was “bad”.

    for more cool sh!t check out their forums. a few college kids (a few years ago) took apart the evaporator of a fridge, reworked the tubing, and super-glued the _evaporator_ to the _core_! solid core temps below freezing at all loads. insaine!!!!

  13. Use mineral oil instead of any veg based oil.
    Second you some type of electronic cooler mounted above the level of the cpu with a heat sink out side of the oil could make for an effective cooler.

  14. As per what kind of oil to use, It is simple:

    1.) It shouldn’t rot easily
    No Olive oil etc.
    2.) It should have the highest possible resistance (e.g. lack of conductivity)

    Pure water is 18 mega ohms… that would work, but it would be impossible to keep dust out of it and it would then conduct. Has anyone dipped a multi meter in

    1.) Motor oil
    2.) Transmission fluid
    3.) peanut oil
    4.) Canola Oil
    5.) Mineral Oil
    6.) Cod Liver oil etc etc.

  15. Didn’t anyone ever see the article on the guy who used this super expensive liquid made by xerox I think. He used a modified ice chest to put his computer in, and actually had the liquid pumping through a radiator submerged in liquid nitrogen. It was pretty extremem but his post speeds were ridiculous.

  16. Yeah, i used vegetbale oil i think 3 years ago, stuck the whole thing in an old freezer i ahd, ran extension cable for everything out through holes i drilled, and it worked fine. too bad the freezer was loud, otherwise it would have been silent

  17. @ stephen crosby: it’s called Fluorinert & it’d made by 3M, costs ~ $500/ gallon i believe. A cheaper alternative is midel 7131, which was designed to cool transformers, not sure what it costs, but I know its cheaper than fluorinert. I have heard mineral oil is the best thing to use if you’re poor like me. Here is a guy who did a damn nice mod using midel 7131…


  18. be careful if you add colorants or disinfectants. you could accidentally introduce a conductive component, and then your oil/coolant simply becomes a short circuit.

    for the same reason, you should try to limit the amount of dust that enters the tank.

  19. when picking mineral oil, the best is pure muneral oil.

    however, keep in mind that even so called “pure” mineral oil at stores has chemicals in it.

    i stress _”P.U.R.E”_, look at the containers.

    there is no need to use anything else, it handles below freezing, it does not evaporate, nor does it conduct. pure mineral oil is perfect. I suddenly really want to do this…

  20. Definitely stay away from vegetable–I just spent the last week cleaning some parts that had congealed vegetable oil.

    The following link has the conductivity of various substances. Hydraulic fluid looks promising but I don’t know if it is hydrophilic.


    What you really want is Fluorinert


  21. another thing to consider is that a lot of oils are hygroscopic which means that unless you seal the system you are going to be slowly adding water to it.
    An interesting concept would be a refrigerated/oil cooled system whereby the motherboard is immersed in oil, an airtight lid is fixed to the top of the tank and the necessary cables come up through an airtight seal, the air above the oil. You could then pull the air out of the tank and replace it with refrigerant. From my experience, the cheapest and easiest to work with would be ammonia, as you could use plain mineral oil in the system. You could then take a suction line from the top of the tank to a compressor and condenser, and just bubble the liquid back through the expansion valve at the bottom of the oil. Without running the suction on a vacuum you could still achieve oil temps of -30.
    Actually, now i think – the easiest way to route the cables would be through a length of stainless tube which comes through the sealed lid and ends underneath the oil.
    When i get a bit of spare time at work i will make such a system and post pictures and test results for you all.

  22. Oil filled xformers are routinely used in power distribution. Askarel was the best, but it has PCBs so is no longer available. Meter it first, then vent through silica gel to keep moisture out. Note however that a short circuit in oil might start a fire [that was the advantage of Askarel].

  23. someone should get some lard melt it down and put their motherboard in it the chill it so it becomes a solid motherboard lard block that is kept chilled cooling the motherboard i think that would be pretty sweet

  24. A friend of mine did this with mineral oil in our high school CIS class…i have been considering doing my own project with MIDEL 7131…does anyone have suggestions concerning how to keep the liquid cool? obviously running it through a radiator of some sort is necessary, but is air going to be enough to cool it? could i use a pump from a plain old fish tank to move the liquid around? if air is not enough cooling, could said pump handle the temps of dry ice?

  25. The following low-cost fluids will work for immersion of electrical parts:

    Luminol TR-i*
    Midel 7131*
    Mineral Oil
    Silicone Oil
    Vegtable Oils

    I am having trouble finding sources for the two most desirable fluids (Luminol/Midel) – does anyone have any tips on where they can be purchased?

  26. ——Martyn Compton

    probably sound stupid but do oyu still need a heatsink etc on top of the processor?——–

    Unless you have an extremely (and constantly) high rate of fluid flow acting upon the CPU a heat sink is recomended! ;)

    Your question prompted me to some thinking, however! The large heatsinks that come with or are purchased for a CPU are made with air-cooling in mind. If immersed, such a large heat-sink will probably actually INSULATE the processor to a small degree (depending upon fluid flow rate and temp.) With this in mind, a high-flow system should probably be built using a smaller heat-sink.

  27. you have a good point shamrack, is the heat conductivity of say mineral oil higher than that of a heatsink of aluminium, if it is then surely a smaller heatsink would be beneficial

  28. There are inherent problems with the full immersion liquid cooling systems, namely involving what oil to use. First, you have the professional grade oils: the ones that cost hundreds of dollars a litre. This (obviously) is unappealing to anyone who is not looking to spend a lot on one of these systems. Then, the cheapies: the natural oils, the kind you can go down to Von’s or Ralph’s or Piggly Wiggly whatever! to buy. These, as most of you know, were meant for human consumption, and because of this fact, they can be used by microorganisms for their consumption. Nobody wants 10 litres of rancid corn oil in their room, right? So here’s my idea:

    1) Get fish tank.
    2) Put parts in.
    3) Submerge in biological oil of choice.
    **Now, the key!**
    4) Add beta-mercaptoethanol.
    5) Remove most of the air and seal.

    Bam! Problem solved. For those of you who don’t know, beta-mercaptoethanol (hydrogen sulphide gas with ehtylene oxide) is an agent commonly used in biological applications as a non-selective germicide. I’ve used it most often to destroy impurities in protein slurries to prevent further corruption (I’m a research technician at USC). ANYWAY, the point is that adding this to your oil of choice then (semi-)vaccuum sealing it minimizes (if not eliminates) your chance of your oil rotting. Beta-mercaptoethanol is, if memory serves me, 400x, so for 10 L (~2.6 gal), all you would need is 25uL to do the job. Very appealing if you ask me.

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