would this work?

deicistdeicist Manchester, UK
edited March 2006 in Hardware
OKay, I'm thinking of looking at some sort of exotic cooling solution, and I was playing around with some ideas.... just wondering if this will work?

Get a peltier cooler, attach a quality heasink to the 'cold' side and have it immersed in the reservoir of a water cooling system, while the 'hot' side is attached to a heatsink & fan combo. The peltier then cools the water, which cools the CPU / GPU / whatever while the heatsink and fan cools the hot side of the peltier. I'm thinking of using Big typhoon heatsinks on both sides. I'd imagine I'm not the first person to come up with this idea, anyone seen it before?
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Comments

  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited February 2006
    just...... wow..... That's dedication :eek2:

    :thumbsup:

    BTW: We would almost definitely publish something like that if you decided to write an article about it ;)
  • ArmoArmo Mr. Nice Guy Is Dead,Only Aqua Remains Member
    edited February 2006
    It'll freezse the water. we are talking temps around -30C
  • deicistdeicist Manchester, UK
    edited February 2006
    hmmm, I'm not so sure, if you keep the water moving and maybe add some kind of impurity to raise the freezing point it should be okay... just have to remember to switch the peltier off before you shut the pumps down.

    So, any experienced watercoolers give me any advice on waterblocks / pumps etc?
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited February 2006
    Don't use water. Use something inert like mineral oil
  • deicistdeicist Manchester, UK
    edited February 2006
    That would be more difficult to pump though wouldn't it? It's more viscous... Also, I'm assuming there's some reason that people use water instead of mineral oil despite the oil's lack of conductivity.
  • profdlpprofdlp The Holy City Of Westlake, Ohio
    edited February 2006
    I know that there are some corrosion issues to consider, but what about using anti-freeze?
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited February 2006
    well normally people would use water because it's easy and there's no problem with using it - but in an exotic setup like that, water becomes unusable and you'll probably need to figure out something else.

    I think that, despite the circulation and the warmth gained from the CPU, etc, water would still freeze at -30c. Even if it froze just around the cool sink, it would still seriously stifle the efficiency of the whole thing.
  • deicistdeicist Manchester, UK
    edited February 2006
    hmmm.... well let me see if I can find a (reasonably) cheap peltier element from somewhere and I can experiment with various liquids :)
  • profdlpprofdlp The Holy City Of Westlake, Ohio
    edited February 2006
    deicist wrote:
    hmmm.... well let me see if I can find a (reasonably) cheap peltier element from somewhere and I can experiment with various liquids :)
    I have an old one from my Socket 7 days. I'm not sure of the wattage, but the last time I tested it it worked fine. If you want it, it's yours. :)
  • deicistdeicist Manchester, UK
    edited February 2006
    Prof, once again you da man :)

    Just out of interest what does the element actually look like? I'm imagining something like a processor with no pins and a couple of wires coming out of it, just a flat plate that gets hot on one side, cold on the other but I really have no idea. Can you enlighten me? maybe take some pics?

    edit: on reflection I don't think I'll be hooking this rig up to my opty just yet, I'm going to buy the cheapest socket 939 board / CPU I can find and use that as my test bed... so it's going to have to go on hold for a month or so while I dig up some cash :D
  • profdlpprofdlp The Holy City Of Westlake, Ohio
    edited February 2006
    Here are some pictures. The element itself (the white part) is 4cm square:
  • deicistdeicist Manchester, UK
    edited February 2006
    Okay, that looks pretty cool... at least for testing purposes, how would you like me to sort out postage etc?
  • rykoryko new york
    edited February 2006
    what about using alcohol? it won't freeze....
  • deicistdeicist Manchester, UK
    edited February 2006
    Good idea, but alcohol has a much lower specific heat capacity and thermal conductivity than water, so it wouldn't freeze but it wouldn't conduct heat very well either. Anyway, if I can get a peltier to try it with I'm going to test various liquids and see how I get on.
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited February 2006
    Wouldn't alcohol evaporate way too quickly to be effective (besides the bad thermal properties)?
  • deicistdeicist Manchester, UK
    edited February 2006
    ah yeah, that's another interesting factor....

    Anyway, thanks for the offer prof but I've just had a look on Ebay and I can buy a 170watt peltier for (probably) cheaper than it would be for you to post me yours... supercooling here I come :)

    I'll make sure to take pictures of every step so I can post them here :)
  • profdlpprofdlp The Holy City Of Westlake, Ohio
    edited February 2006
    That's fine. I doubt that this one is anywhere near 170W. I wasn't worried about the postage - this thing is very light due to the antique aluminum Socket 7 style HS. :)
  • deicistdeicist Manchester, UK
    edited February 2006
    Well my first job is going to be getting a peltier and a couple of heatsinks to make my cooling rig. For this I'll need:

    Peltier: Linky I'm thinking the 220w one from the bottom of that page.

    Peltier power supply: this thing probably won't run off my PSU so I'll need a quality 12v power supply. There's one on that page above, but it's quite expensive. I'm thinking there must be other applications that use 12v but don't have the markup that PC equipment has.

    A 'cold' heatsink (ha ha) for attaching to the peltier cold side and dunking in my reservoir. This is going to be problematic, I need a decent heatsink that doesn't use heatpipes since it'll be inverted and (hopefully) below 0 degress, heatpipes won't work.

    a 'hot' heatsink & fan. This can be a heatpipe based model, because it'll be mounted the right way up and will have a lot of heat to deal with. I'm considering a big typhoon since I've heard good things about them.

    Once I have all these things I need to mount them together. Hopefully the heatsinks will have compatible fittings and I can just screw them together with the peltier sandwiched tightly in the middle. Not sure if that'll work but I don't see why it shouldn't.


    then, with the active part of the rig out of the way I'll need to build a reservoir, since I doubt any standard ones will be big enough to fit the heatsink in. I'll also need a way of sealing the heatsink in there whilst still having good thermal contact with the peltier. Could be tricky. Especially since I have no previous experience with building any kind of water container.

    Then I need to look at a pump and tubing. Oh and a waterblock. I've never dabbled with watercooling before so it should be an interesting learning experience.

    Anyway, I'll be sure to keep you all updated with how I'm getting on.
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited February 2006
    For the cold sink, how about an SLK-900 or something? Oldie but a goodie :)
  • LeonardoLeonardo Wake up and smell the glaciers Eagle River, Alaska Icrontian
    edited February 2006
    I'm not so sure, if you keep the water moving and maybe add some kind of impurity to raise the freezing point it should be okay...
    Just an observation and recommendation:

    Pure water will not freeze. Impurities in the water act as particles around which water crystalizes into solid form (ice). But purified water, in the literal sense, can only be had from highly specialized laboratories. OK, physical science now squared away. Recommend you use 100% anti-freeze. I wouldn't mix it with water or anything else. It shouldn't freeze, unless you get cheap stuff. Also, if you mix water with it, and it's not purified (not the stupid stuff from store shelves, but distilled, perhaps even deionized) you will just add to corrosion through interaction of any minerals that would be in the water. 100's of millions of car radiators around the world run antifreeze without corrosion problems, unless mineral-laden water is added. There ought to be some type of coating you could add to the heatsink to inhibit corrosion. Or...hmm... many of the automotive coolants today are formulated for aluminum block engines. If it's OK for an aluminum alloy block, why not for an aluminum heatsink? Recommend you talk with an experienced automotive technician. Those guys understand aluminum, cooling, and corrosion quite well.
  • deicistdeicist Manchester, UK
    edited February 2006
    primesuspect wrote:
    For the cold sink, how about an SLK-900 or something? Oldie but a goodie :)

    Just done a quick google since I'm not familiar with that heatsink...it seems to be exactly what I'm looking for though, a big slab of finned copper :D

    my only concern would be with the mounting holes on it. I want (ideally) 2 heatsinks with the same mounting points so I can just screw them together. Anyway, I'm a fair way off buying heatsinks yet, I'm still in the 'throwing ideas around' stage
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited February 2006
    Then you probably want an SLK-947U :)
  • profdlpprofdlp The Holy City Of Westlake, Ohio
    edited February 2006
    deicist wrote:
    ...Peltier: Linky I'm thinking the 220w one from the bottom of that page...
    I had no idea that they were so much cheaper these days. A rough conversion from pounds to dollars indicates that this one is about half of what I paid for a much smaller unit years ago.

    Looks like a great deal. :)
  • sfleurietsfleuriet Texas New
    edited February 2006
    I have no logical input to offer, but cool thread :cool:
  • tmh88tmh88 Pittsburgh / Athens, OH
    edited February 2006
    i never really understood peltiers. I know they get really cold, but how?
  • primesuspectprimesuspect Beepin n' Boopin Detroit, MI Icrontian
    edited February 2006
    Wikipedia is your friend
  • deicistdeicist Manchester, UK
    edited February 2006
    Been googling all day at work for parts for this project and so far I'm at a bit of a standstill...

    For the 'cold' heatsink I was thinking of one of those huge Zalman flower coolers, which would seem to be ideal. Finding one in the UK is proving to be a pain though.

    The 'hot' heatsink is easier, just need to wait and find the 'cold' one first so I can be sure I can fit them together.

    The main problem (and expenditure) is going to be the power supply. Cheapest PSU I can find that will do the 20A or so I need at 12v is around £50 or so. Was hoping to find a cheap alternative power supply (like a car battery charger or something) but they don't supply anywhere near the current I require. Oh well.
  • deicistdeicist Manchester, UK
    edited February 2006
    Leonardo wrote:
    Just an observation and recommendation:

    Pure water will not freeze. Impurities in the water act as particles around which water crystalizes into solid form (ice). But purified water, in the literal sense, can only be had from highly specialized laboratories.

    I'm pretty sure that isn't correct.... Pure water doesn't conduct electricity very well (due to lack of free electrons or somesuch), but it certainly freezes no matter how pure it is. Maybe it doesn't crystalize in the same way as water with impurities, but it does freeze.

    Edit: Done some more reading on this, apparently very pure water can be cooled to below 0 degrees without freezing in certain circumstances, but it will still freeze eventually.
  • TheSmJTheSmJ
    edited February 2006
    I’d hate to piss on everyone’s bonfire, but unless I misunderstand the laws of thermodynamics and physics this won’t work at all.

    Large CPU heatsinks like the Big Typhoon are only designed to take around 100W of heat max. Cooling 220W, plus whatever heat it pulls out of the water would be an impossible task for this cooler.

    The problem with peltier coolers is they create far more heat then they are able to displace. This is why heatsinks with peliters mounted on the bottom (using 40W peliters max) disappeared after the early Pentium MMX era. You may require another water cooling system altogether to cool a monster 220W pelt, or a truly monstrous heatsink which could rival the computer case itself.

    If you really want to cool your CPU to below freezing temps without going phase-change, sandwich the pelt between the CPU and the waterblock, and use a large radiator to cool the water. This is a tried and true method, and is the reason why some retailers sell both waterblocks and pelts in a package.

    As far as water blocks go, my recent research shows that either the DangerDen TDX or the latest offering from Swiftec (whose model name I forgot) are both very good performers. I would imagine at least one of these models could be found in the UK if not both.
  • deicistdeicist Manchester, UK
    edited February 2006
    Well I have an update, started buying parts :)

    I got a 170 watt peltier off Ebay for £20.

    For the 'hot' heatsink I went for one of these:
    water_mark_ak_913.jpg

    An Akasa 'Evo 33'. Probably nowhere near the best, but it was cheap and I have one cooling my opty which seems to work well enough.

    Now for the exciting bit, the 'cold' heatsink. I had a dig around in the parts cupboard and I found this beauty strapped to a PentiumIII (see attachments) It's basically a big slab of aluminium (nearly the size of a hard drive) which is a pretty handy shape. I should be able to dill into it to create mounting points for my 'hot' heatsink and just sandwich the peltier between them.

    Hopefully all this should arrive tomorrow (although I'm not really expecting the peltier til friday or even next week given it's off ebay). I'm going to try my luck with a standard ATX power supply I have lying around. the 12v rail isn't really rated for what I want it to do but I won't miss it if it blows up.
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