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Using Radiators to Cool CPUs 245

dan writes "Overclockers Australia have a review up of the CPU Radiator Zen, a new approach to cooling your toasty CPU's. Rather than taking the traditional approach of a heatsink with lots of fins and a noisy 7,000rpm fan it uses radiator/heat pipe technology. The implementation of the unit is a bit flawed, but it is interesting to see where the technology is heading.. and if it can be done right I personally think this is where it will end up."
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Using Radiators to Cool CPUs

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  • Silent? (Score:3, Interesting)

    by chrysalis ( 50680 ) on Wednesday November 07, 2001 @12:54PM (#2533083) Homepage
    How silent is this? It's cool for overclocking, but if it's silent, it could also be very cool for music makers.

    • Re:Silent? (Score:2, Informative)

      by Chakat ( 320875 )
      It looks like its still farily loud. It's got two fans on it, so it's going to make a good amount of noise. Unfortunately, it's not the fanless system I was hoping for when I checked it out.

      Plus, it looks like its not good for OCers. The device is very poorly designed, and busted caused damage to both the CPU and Mobo.

  • take a large copper cloth flat grounding wire, and attach to cpu. take the other end and attach to case. noisless cooling.
    • Good idea in theory but that won't move heat quickly enough for powerful cpu's. Also, your case would get very warm and act like an oven around your hard drives and other components. You'd have to drastically increase airflow through the case in order to keep the rest of the system cool, which would defeat the noiseless aspect of the copper wire cooling method. With cpu heatsinks, the heated air is usually vented right out without circulating to the other components.
      Without a real heatsink that has a large air-exposed surface area a relatively short distance from the chip, you'll wind up with an impressive heat gradient across the wire.
      An Athlon chip will get up to roughly 600-700 degrees (F) within just a few seconds of power-on if no heatsink is attached. The copper cloth wire might bring it down a bit but you're still talking about having something exposed inside your case that's hot enough to melt wire insulation and probably catch dust on fire (after your system crashes of course).
  • don't laptop's already have this?
    • I know that there is a company called Thermacore does it for Dell laptops. I have been able to play around with their heat pipes and they are amazing. I believe Thermacore does product for any laptop product higher than a C600. So to answer the question.. YES! Are there anymore company's like this besides these 2?
  • Althought I don't have a link, I know they've done this as far back as the first pentiums. If I recall correctly, this was the ONLY way they could get the very first [then] brand-spankin-new Pentium's to work.
  • Noisy Fans? (Score:3, Insightful)

    by FortKnox ( 169099 ) on Wednesday November 07, 2001 @12:58PM (#2533105) Homepage Journal
    a noisy 7,000rpm fan

    Maybe I'm just an old-school style computer guy, but is fan noise really that big of a deal? My computer is in an infants room and it doesn't wake up the baby (counterstrike pumped through 4 speakers does, but that's beside the point). Honestly, who has a huge issue with fan noise?

    And why always complain about CPU fan noise? Doesn't the fans in the power supply make more noise, anyway?
    • Another thing...
      By looking at the pictures, it appears that the "radiator" is replacing the heatsink, and they still have fans on top.
    • I'm just an old-school style computer guy, but is fan noise really that big of a deal?

      I don't think it has anything to do with being "old-school style" -- apparently you're just not a musician! Those of us who do musical work with our machines half the time and have hyper-sensitive ears the rest of the time find fans quite irritating.

      Doesn't the fans in the power supply make more noise, anyway?

      Not in my laptop! :) It's soooo close to silent, but darn, if I could just squeeze it down a few more decibels....
    • Try working with a fanless desktop computer -- e.g., an iMac -- for a while and then go back to your regular desktop. See what a difference it makes. Fan noise never used to bother me until I got an iMac at home; now sitting down at my desk at work bothers the hell out of me for the first hour or so, because I'm always aware of the noise from the CPU. And I'm convinced that even if one isn't aware of it, the constant background noise harms productivity.

      Not that it harms productivity as much as posting to /. when one should be coding, of course ... ;)
    • Health Issues (Score:5, Informative)

      by squaretorus ( 459130 ) on Wednesday November 07, 2001 @01:23PM (#2533246) Homepage Journal
      There is a documented link between low level noise and hearing and stress levels in those spending long times exposed to them.

      The hum of a fan, whatever it is cooling, is often at a level that you might strain to hear clearly. It is these levels that can cause hearing strain. This is similar to eye strain when you need glasses and can give you monster headaches.

      Many articles in New Scientist, among others, have covered this - normally relating to office environments.

      Symptoms can be migranes, and a persistant ringing / humming sound when you are in a silent room / trying to sleep. Its worth checking out if you feel any of these because the long term stress levels can be harmful.

      I don't know if its a problem for babies - but I know the effects are magnified many fold if you are exposed for long periods, i.e. all night. So I wouldn't leave the machine on 24/7 even if the baby doesn't seem bothered by it 'just in case'.
    • The answer is obviously YES...

      When I left my last company I had a dual Xeon system (3-4 fans if I recall) and a bunch of network switches, other boxen, etc. each with their own fans...

      When I powered down when I left, I was SHOCKED at how quiet my cube got... I just keep a laptop in my cube now and use X/SSH/etc. to get at the "real" work machines that are elsewhere... I love the quiet.
    • Re:Noisy Fans? (Score:2, Interesting)

      by Peter Dyck ( 201979 )
      is fan noise really that big of a deal?

      Fans make noise. Period.

      I'm one of those individuals who are simply driven mad by excessive computer noise which means that anything over 50 dB is intolerable. In fact, some time ago I sold my 600 MHz Duron PC because I couldn't stand the noise the CPU fan alone made. A CPU fanless Sun Blade 100 with a low rpm hard drive was heaven after the previous noise polluter (the power supply still makes noise, though). I'm quite content with the trade-off I had to make between computer speed and noise.

      I still blame the CPU manufacturers for ignoring the heat problem (=noise problem) at the altar of unnecessary performance, though.

    • Your babe tolerates certain levels and sleeps through others.

      For her (him?) it's Counterstrike. For others it's the fan on the CPU. For other's it's the whirring of the CDRW drive.

      Me, I use a PowerBook because I *love* silence. I listen to my music *quiet*, so when the CPU or PS fan is louder than my music, I have issues.

      My *new* PC is an 800MHz Celeron with a low speed fan and a 140W PS in order to supress noise. Tradeoffs of power and heat for noise and performance.
    • one problem with your reasoning is that babies like soft white noise. at a resurant, babies sleep because the background noise is soothing and hypnotic. ever wonder why all those crib toys come with an option of waves or wind?
    • And why always complain about CPU fan noise? Doesn't the fans in the power supply make more noise, anyway?

      It sounds like you haven't actually HEARD the sound of a 60mm 7,000rpm Delta Black Label fan.

      Imagine a hair dryer. On it's fastest setting. Sitting inside your PC.

      That's the sound one of those fans makes. It takes a LOT of effort for a 60mm fan to move 38cfm in a free-air environment - then add to the fact that you're trying to push that airflow through a heatsink, which creates even MORE noise, and your fan gets louder again. It's not unusual to hear of HSF units with Delta Black Label fans rated at 48dBA. And that doesn't take into account the fact that the noise is very high pitched as well. It makes your PC sound like a jet plane readying itself for takeoff. It can *really* get on your nerves. Trust me.

      Power supply fans tend to be pretty damned quiet in comparison. Especially when Panaflo fans (or similar) are used - they're known for being quiet.
  • Has this... (Score:2, Informative)

    by rmadmin ( 532701 )
    already been done? I do believe that one of the Cray models had a 'liquid cooled CPU', or something to that effect. I never saw the specifics on how it was done, if it was just the CPU, or if it was the whole machine being cooled that way.

    I also remember someone else (Penguincomputing?) having the '1st commercial liquid cooled PC', which was a 1.6 Ghz(2x800Mhz) Dual Athlon.

    Either way, its really cool to see this same technology replicated for private use.

    • already been done? I do believe that one of the Cray models had a 'liquid cooled CPU', or something to that effect. I never saw the specifics on how it was done, if it was just the CPU, or if it was the whole machine being cooled that way.
      That's one of the most famous design hacks in computer hardware history (although that statement itself is a bit unfair, given the percentage of high performance hacks directly attributable to S. Cray): the entire processing section was submerged in liquid Freon, several hundred liters worth. There was a glass section so you could look in as with an aquarium, too.


  • by melquiades ( 314628 ) on Wednesday November 07, 2001 @12:59PM (#2533112) Homepage
    I remember seeing years ago on public television somebody demonstrating this amazing liquid which, I believe, was called "chlorinert". It looked and behaved more or less like water, but it was completely nonconductive. The guy demostrated by plugging in a lamp, submerging it in the liquid, and screwing in a bulb while it was submerged. It was pretty amazing.

    They mentioned its possible application to CPU cooling in supercomputers -- the idea was that you would actually submerge whole circuit boards in the liquid, while pumping it through a conventional refrigeration unit. Heat sinks be damned!

    Apparently it never caught on, though -- I can't find anything about it online. Even mighty google just says, "Did you mean 'chlorine'?" I think it was incredibly expensive; perhaps that's the reason.
  • by Chairboy ( 88841 ) on Wednesday November 07, 2001 @12:59PM (#2533114) Homepage
    Me: "My computer has been making a strange sound."

    Computer Mechanic crawls under my computer, then slides out a few minutes later and wipes oil off his hands with an old shop towel. "Looks like your radiator fan has lost a bearing. I can replace it, but I also have to put on a new belt. The old one is almost wore down. Also, you need an oil change. These new Septium-6 processors can really eat up an oil filter quick, and the color of this stuff is pretty dark now.

    Me: "Boy, I remember when computers were so simple, I could just pop off the case and swap out components on my own."

    Computer technician: "Ok gramps, whatever you say. You just sit yourself down out in the lobby and I'll have Betsy ring you up once I'm done. Shouldn't take more then a couple hours. Oh, and the tread on your network connector looks a little thin, can I suggest a new pair?"

  • This is not a new idea. This has been done before [wizard.com].

  • In most cases, using a radiator means pumping water into your computer. And THAT is one big source of trouble. Just imagine what happens if one of the pipes cracks, or if a joint falls off!

    And, my Athlon 1,5Ghz will instantly boil any water because it's ONE HOT MAMA!
    • They're using heat pipe technology to move the stuff about- that doesn't mean water. Furthermore, radiators do NOT mean water is involved- alcohol or ethylene glycol work rather well in radiator applications (which is why I keep wondering what these people are thinking when they run liquid cooling systems with water.
      • Water has a higher specific heat capacity than ethylene glycol, and therefore is better for transferring heat. The antifreeze in your car's radiator system is there to 1) stop the water from freezing, expanding, and breaking your engine/hoses/radiator and 2) to keep the aluminum parts from corroding.

        Don't believe me? Drain your car's radiator, then fill it up with pure antifreeze. Your car will now run much hotter than it did before, I promise.

        Alcohol, on the other hand, would be fine, I guess - as long as you keep it away from fire and stuff.
        • Drain your car's radiator, then fill it up with pure

          Doesn't matter. Either pure water or pure anti-freeze will give worse cooling than a proper mixture of anti-freeze and water. the mixture resutls in higher boiling points than either alone, and lower freezing points than either alone. Note that for each of the above you need a different mixture. 50/50 tends to be optimal for most people. In Minnesota we lean closer to 70/30, and in the desert (I think) they lean a little the other way. It turns out that 70/30 is close to the lowest freezing point you can achive with anti-freeze/water mistures. However the boiling point and heat capacity is changed.

          • The reason why I suggested ethylene glycol alone in a liquid cooling system is that it's non-conductive with a more than passable heat capacity. Mixing in water brings back the risk of conductivity (any impurities of an ionic nature and it's conductive...)- while it'd work better than water alone or antifreeze alone, it's not what you're striving for with antifreeze alone.
        • I know that. However, it's NOT conductive (Like with all cases of water except high-purity distilled...) and while it's not as effective as water, it's still more effective than convective cooling (because air has a lousy specific heat capacity even compared to ethylene glycol)- it'd work fine. I'd not take chances with a leak and water...

          Alcohol wouldn't be exposed to fire and stuff inside your computer (unless you've got worse problems... :-)
          • Sorry, no pictures online yet, other people have plenty however. I got my kit from cool-computers.com, but there's lots of other ones out there. You don't use alcohol in a liquid cooled system because not only is it flammable, the vapours are extremely explosive. If you had a minor vapour leak, the slightest spark inside your computer - like, oh, say, a motor, a bad capacitor, your power supply, whatever - would cause an explosion. Alcohol at near purity running at ~40C is also extremely flammable. That's INSANE.

            Please, nobody attempt to use alcohol to liquid cool a PC. It's dangerous. If you want to experiment with other liquids with higher specific heats, try an oil instead, but understand the risks. No, I'm not responsible if you blow up your machine. Distilled water is a wonderful insulator, too. No worries there. $1 buck for 4 liters at the local Walmart. Hardly exotic.

            I'm running a athlon 1.2G mildly overclocked (1.3g) with the entire apparatus inside a mid tower case. I got sick of my work machine locking up because of overheating (the lab I work in has poor ventilation and gets extremely hot). Liquid cooling works extremely well, but it's far from plug and play and definately not something for beginners. :)

  • by legLess ( 127550 ) on Wednesday November 07, 2001 @01:01PM (#2533126) Journal
    I know where it'll end up: just like Reason in Snow Crash. Boxes will be nuclear powered and you'll have to have the heat exchanger immersed in water the whole time or it'll melt down.

    In all seriousness, I do think this is the way things'll go. Remember all those air-cooled Volkswagen buses? Remember how people bolted radiators onto the side of them so they wouldn't explode in hot climates? Air-cooling will only carry you so far, especially with dinky little fans. For serious cooling you need serious metal-to-metal heat exchange.

    • You never owned an air-cooled VW, did you?

      Those radiators are oil coolers. Air cools the cylinders, which are finned like motorcycle cylinders. Oil does the rest of the job, besides lubricating, it soaks up much of the heat. Running the oil through a small radiator makes a large difference in some climates, but is usually unnecessary. Shoot, in Israel (commonly accepted as a pretty hot climate) they run without 'em just fine.

      The reasons to add the radiator for oil-cooling are:
      exposing the oil to a finned, air cooled radiator cools the oil off faster, leading to a cooler engine, and

      having greater oil capacity means that the oil is more resistant to heating up, and adding the oil cooler adds more oil capacity.

      And remember, the air-cooling on the VW is the same as it is on air-cooled porsches, a fan on the back of the generator (alternator) driven by a belt off the crankshaft. Pretty darn efficient.
  • Great, at this rate, we'll have tricked out computers a la The Fast and the Furious
  • by El Puerco Loco ( 31491 ) on Wednesday November 07, 2001 @01:02PM (#2533135)
    it was cool when you could jack a celeron300a up to 450mhz and have it run faster than a pentium 450 at less than half the price, but with most processors today you're looking at maybe a 5 or 10 percent gain and maybe a 20 or 30 dollars in savings. the savings is nil when you have to buy a fancy cooling solution to keep running
    • Celeron300A -> 450Mhz = 150% speed increase.

      My 1000Mhz Athlon -> 1450Mhz = 145% speed increase.

      I would never say that overclocking is necessary, but it's still giving the same sort of performance boosts today as it did a few years ago. When I got my 1Ghz chip, 1.4Ghz Athlons weren't even available yet. And when they did come out, they were far more expensive than what I paid. My 'fancy cooling solution' is a Globalwin FOP-32. It doesn't sound like a hairdryer and it's quite efficient and cost me about US$15. So the cost benefits are definitely still there too.
  • Wow, this is sort of based on the same principle as refrigerators and airconditioning units. It looks like it will be extremely effective at cooling down an overclocked CPU.

    As someone who has never overclocked my CPU, I have nothing but admiration for those brave souls who risk destroying their hardware, and being prosecuted under the DMCA all for the sake of a few extra MHz. It is this pioneering spirit which shows why time and again hackers (not crackers) are at the cutting edge of computer technology.

    I pity the poor tech support person at CompUSA when someone brings one of these suckers in for repair though. Looks like it will need a plumber as well as an electronics wizard, and we all know how expensive that can be :-)

    • being prosecuted under the DMCA

      why? I really don't follow...

    • ...and being prosecuted under the DMCA all for the sake of a few extra MHz.

      Um, please DO tell me you're kidding.

      What I, or anyone else, chooses to do with my processor after I buy it is MY business. We're not talking about art, or artistic license here, but a consumer electronics product.

      The only time it becomes illegal is if, through the process of overclocking, I damage the CPU, and then try to claim warranty - that's fraud. Otherwise, if I want to run my 1GHz Athlon @ 1.5GHz, there's no-one who has the right to stop me.
  • by Sara Chan ( 138144 ) on Wednesday November 07, 2001 @01:03PM (#2533141)
    I've got a 1998 Twinhead [twinhead.com] laptop that uses heat pipe technology for cooling. The laptop also has a fan, which almost never goes on, due to the heat pipe. (It was for the quiet fanless running that I bought a Twinhead.)

    Twinhead advertising claims that their heat pipe technology is patented. I've no further details and couldn't find anything relevant on their web site.

    Buy Windows XP. Give Bill Gates even more of your money.

  • Not that they are all practical but man they look so cool.


  • This is causing me to have "far-side-comic" images of people with their sleeves rolled up in their offices, peeking under the "hood" of their desktop machines, with steam bellowing out of them.

    "Just let it cool down for a few minutes, and start her up again."

    Ever driven through the desert.
  • by Jeffrey Baker ( 6191 ) on Wednesday November 07, 2001 @01:05PM (#2533149)
    No this is hopefully NOT where it (CPU cooling technology) will end up. Ideally, it will end up with CPUs that consume less power and give off less heat, can withstand higher core temperatures, and can more efficiently transfer heat outside the core. Slapping a vapor refrigerator onto the CPU is the opposite of elegance.
    • It's not a "vapor refrigerator" but a heat pipe. It's non-powered, except for the fans that blow air through the radiator part of it. You could eliminate the fans by making the radiator larger.

      Cost/performance ratio doesn't sound so good though. ($85 for cooling 10 degrees C better than an ordinary heatsink/fan, and not quite as good as the best performing (and enormous, I suppose) HSF's. Heat pipes are NASA technology, and there are few cost-effective applications on Earth. But if you really want a _quiet_ Pentium 3 or 4 system, your choices right now seem to be either immersing the motherboard in liquid, or a heatpipe to carry the heat out to a big fan-less radiator. Or else run non-bloated software on a CPU that doesn't need extreme heatsinking...
    • I think that oneday, by accident, a chemist will create a room temprature super conductor. this is where computing will go next, since quantom computing is about 50 to 100 years away.
  • um, guys? (Score:1, Insightful)

    by b0r1s ( 170449 )
    I agree that this is cool, but come on now, why are we posting stories about something that doesnt yet work? Can't we wait until it 1) works well (the page states that other high performance heat sinks with large fans outperform it), and 2)doesnt damage the chips (We first tested the Zen Radiator, then the PAL 6035, and finally the MC462. After the first run we thought it a good idea to run the test again with the Zen Radiator in order to verify our results. This turned out to be a bad idea. The installation was again rather painful. Again a lot of pressure and time was necessary until we finally managed to connect the Zen Radiator with the socket. After powering up, the OS did not boot. To make it short: when mounting the unit on the socket, we had damaged the CPU. Chunks from all 4 corners of the die were broken off.)...

    It's cool and all, but if this were software, it would surely be beta. Do we really need beta announcements? (*cough* mozilla *cough*) ...
  • Hasn't this been done before, or is it just a different means of water cooling?

    No matter how well-sealed they say it is, I don't trust water flowing around my machine. Call me old-fashioned, but...
  • A similar change was seen in the auto industry - moving from air-cooled engines like the VW Beetle to the water-cooled VW Rabbit/Golf. I don't know of one air-cooled car left in production, though we still have air-cooled motorcycles (Harley) *sigh* But those Bugs were so easy to work on, and now I have to bring my GTI in to get hooked up to a diagnostic computer ... anyone have a Linux hack for this? Heh heh, talk about voiding warranties ..
  • Well guys if you sat down and read the article all the way through and saw what was going on you could basically understand that this isn't that much of an innovation, just tweaking an already proven practice. People have been using water cooling for years, and basically this just takes water coolings model and just makes it self-contained (at least how I understood it) the only flaw that they are going to run into is keeping the coolant cool at all times which will be hard since in water cooling setups there is a return pipe to the cooler/recycled water..

    Over all I give em two thumbs up for at least tweaking a proven practice, but then again they need some more work to really get the idea going.

  • Other reviews (Score:4, Interesting)

    by alewando ( 854 ) on Wednesday November 07, 2001 @01:07PM (#2533162)
    Other sites have also reviewed the Radiator Zen SCR325-2F:

    The reviews are all favorable, but it's not clear whether this is simply because the reviewers are blinded by the "hey, it's neat!" factor, or whether the Radiator Zen SCR325-2F actually has a legitimate technical advantage. But hey, it is neat, so I can't blame them.
    • Re:Other reviews (Score:2, Insightful)

      by Skuld-Chan ( 302449 )
      Very cool, if it weren't for the fact that they destroyed a motherboard and a processor in the process of installing it I'd be more interested in getting one :).
  • and it physically broke their CPU and their mobo..if it were me, I wouldn't have anything positive to say about it.
  • Also reviewed... (Score:5, Informative)

    by Daniel Rutter ( 126873 ) <dan@dansdata.com> on Wednesday November 07, 2001 @01:10PM (#2533180) Homepage
    ...by, ahem, me, as part of my monster cooler comparison [dansdata.com].

    The Zen review is on page four [dansdata.com].

  • What comes to mind was that article about the blokes who stuffed their computer into freezer. I can't find the link right now.

    But I can imagine that this would be the logical conclusion of this development trend.

    With the engineering and all, it might be just easier to dump everything into a vat of freon in a deep freeze some place.

    or just make a refrigerated rack system.

  • so it would work! (Score:2, Interesting)

    by xcjohn ( 64581 )
    I had used this same basic idea in a project about 2 years ago in a computer project. I've still got the 3d models for it too. My partner for the project and myself were told to design a computer for a specific market and come up with design, info, and a marketing pitch. Let's see if i can find the model.... ha! found it! http://lenin.nu/~jwhite/graphics/gallery/comp [lenin.nu]. basically we had coolant being pumped through a specialized heatsync, through a set up copper coils with fans next to each coil drawing the heat away and pumped back through the heatsync. I always wanted to see it actually implemented.
  • ...if it hadn't DESTROYED their CPU and their motherboard.
  • by BrentRJones ( 68067 ) <slashdotme@brent ... rg minus painter> on Wednesday November 07, 2001 @01:27PM (#2533265) Homepage Journal
    Now for sale: The Mr Coffeee motherboard. (Patent Pending.) Yes it works well, but only on processors over 400 MHz. Makes up to 6 cups per hour.

    Retailer and investor inquires welcome.
  • The idea of using radiant cooling isn't really a new concept in computing... people have been using radiators with liquid cooling implimentations for quite a while.
  • I wonder... (Score:3, Interesting)

    by Atilla ( 64444 ) on Wednesday November 07, 2001 @01:47PM (#2533351) Homepage
    If you would put a thermal generator on a CPU, would you be able to produce enough juice to run a fan? I mean, modern CPU's produce an enormous amount of heat calories...
    • I mean, modern CPU's produce an enormous amount of heat calories...
      So that's why I've been getting fat sitting in front of the computer all day!

    • by SysKoll ( 48967 ) on Wednesday November 07, 2001 @04:48PM (#2534317)

      The average Intel CPU dissipate a waste heat much greater than the few watts absorbed by your average fan. So the idea seems reasonable.

      Alas! The laws of thermodynamics often fly in the face of reasonable ideas. See, if you want to passively cool off the CPU, all you have to do is let it radiate its heat. But what you seem to wish for here is some kind of device that actively cools off that CPU, by taking some of that waste heat as its energy source. That's called a thermic engine. And here, thermodynamics get you: You can generate power from a heat source only if you have a cold "sink". All thermic engines work by getting heat from a heat source and moving it to a heat sink. E.g., for a car, the heat sink is the radiator.

      Here, your contraption would use the CPU as a heat source and would require some sink, such as, oh, a radiator. Maybe with a fan. Which is exactly what we are trying to avoid.

      So it's a nice catch-22. But think about it: if it worked, we would have big ships moving smoothly on all oceans, powered by the extracted heat of sea water and leaving a trail of ice cubes in their wake...

      -- SysKoll
      • Actually, thermodynamics wouldn't forbid this, as the cpu is not running at ambient temperature (in which case we wouldn't need cooling anyway).

        E.g. with a cpu running at ~50C, and a liquid with a boiling point of, say, 40C, you could build a little steam engine, letting the steam condense at room tmperature for the 'refill'. Voilà.

  • by Dr. Evil ( 3501 ) on Wednesday November 07, 2001 @01:52PM (#2533369)

    I mean, you have a radiator which exposes the same surface area as a typical heat sync, but makes less effective contact with the heat source.

    The fluid is probably not doing anything significant at all, the two fans gushing past the aluminum tubes is probably doing all the work.

    I don't even think this thing is actively cooling. There doesn't seem to be any pump... they're relying on the thermal gradient to cause the vapourizing fluid to move to the cool side of the radiator and condense. It doesn't work that way. You need to have some way of forcing the fluid to move in one direction, you need to cause the liquid to vapourize by forcing it through a small opening, pulling heat from the CPU.

    If you can somehow get around that technical wizardry, then you have to find fluids which vapourize at the temperature of the CPU, but condense at the temperature on the other side of the radiator... whatever wimpy thermal gradient that might be... the pressure of the system also remains constant because the whole system is operating passively of course.

    In other words... if you have a CPU at 50 degrees C, and your cooling fluid vapourizes at 40 celcius, then the other side of your heat sync MUST remain lower than 40 celcius, otherwise you just have a bunch of tubes full of pressurized vapour. There is no reason for the cooling side to actually cool especially if the same area is exposed to the CPU as is exposed to the fans.

    On the other hand, if your fluid vapourizes at 60C, it doesn't actually DO anything until the CPU reaches that temperature.

    This is not to say that passive refrigerators do not exist, I just don't think they've built one. They've built a chunk of aluminum full of fluid with two fans blowing through it.

    They should have run another benchmark: Drain the radiator.

    Kryotech has this done right.

  • The Xeons used in Compaq's 8 processor Proliants use a small plate bolted to the processor with two copper pipes. They go up into a radiator assembly, and the server pulls air through them with a very efficient and nice design. I've always liked the design by Compaq on some of their Proliant servers, and how they stay away from putting fans directly on a heatsync. I'll take a hot swappable fan any day.
  • First of all the radiator in you car and the type of heat pipes used in this CPU cooler are similar in principle but radically different in construction and efficiency. The radiator in your car is an open system relying on water+antifreeze. The heat pipe used in many industrial applications (including laptop cooling, my Dell CPx has one that I can see through a grill) is a SEALED pipe with a wick and liquid (usually alchohol) inside. The liquid vaporizes at the operating temperature at any place where there is heating going on and condenses where there is cooling going on. The cool thing about heat pipes is that the heat transfer happens REALLY REALLY fast. For home computing applications (<1 meter) it should be instantaneous. This allows you to move the heat away from where it can do damage to any place you want (within the limits of cost and space of course.). This is also why thin laptops don't fry their CPU's instantly: using heat pipes they can spread the heat sink around and away from the CPU.

    Check out a NASA tech brief [nasatech.com], Thermacore [thermacore.com] a company that makes them and MIC [mic.com] another company that makes them for more information.

    • Heat pipes have been used to cool laptops since the mid to late 90's. The heat pipe transfers the heat from the cpu to the shield around the bottom of the laptop (which is one reason that our laptop often does a good job of warming your lap). The advantage is that cooling fans can be eliminated, which prolongs battery life.

      Most of the heat pipes used in electronics cooling have a copper envelope, copper wick, and use water as the working fluid (operating under a partial vacuum). The advantage is not that they are really fast (the velocity of the water vapor is on the order of meters/second) but that they are very nearly isothermal. (The temperature drop in the heat pipe is essentially negligible, with small temperature drops occurring due to the heat conduction through the copper walls and wicks). This allows you to transfer heat over relatively long distances before removing the heat.

      A second advantage is that heat pipes can be used to reduce the heat flux. The heat flux (watt/cm^2) out of the chip is fairly high. On the other hand, air cooling is relativley inefficient, so a low heat flux is preferred. By using a larger condenser than evaporator, the heat flux can be adjusted to match the capacity of the cooling media. This will become more important in the future, as the heat flux from the chips continues to rise. Some experimental designs water designs have cooled several hundred W/cm^2, which is higher than chips should reach in the near future (high temperature heat pipes - have removed in excess of 50,000 W/cm^2)

      The best introductory book is Heat Pipes, by Chiu, but it is out of print. Dunn and Reay have a reasonable book on heat pipes, but it is quite expensive (~ $100).
  • by Animats ( 122034 ) on Wednesday November 07, 2001 @02:12PM (#2533497) Homepage
    IBM mainframes used to be water-cooled. Cray mainframes used to be Freon-cooled. One Cray machine of the early 1990s actually ran immersed in Fluorinert. All those machines were plumbing nightmares. IBM considered it a big step forward when the water-cooled mainframes were replaced by air-cooled mainframes. Far fewer maintenance headaches. You don't want to go to liquid cooling on the desktop unless there's no alternative.

    Solid-state Peltier-effect coolers are much more promising. They actually refrigerate, they have no moving parts, and they don't make noise.

    • Solid-state Peltier-effect coolers are much more promising. They actually refrigerate, they have no moving parts, and they don't make noise.

      Except that they don't work if they're not themselves cooled. So you're still stuck with using alternative heat removal techniques anyway. Which generally comes down to water cooling (messy and expensive), or very good air cooling (we're back to being noisy again). And if your ancilliary cooling fails, your peltier becomes a *really* good insulator. Meaning you end up with a fried CPU.

      Due to the laws of physics, you also have to remove more heat from the hot side of a peltier than it removes from your CPU.

      And the clamping pressure requires by a peltier to function at it's most efficient is significantly greater than the recommended maximum clamping pressure on the top of either AMD or Intel processors.

      Then there are also problems with condensation. Which is bad when mixed with computer components.

      Peltiers aren't sounding so crash hot all of a sudden, are they... :(
  • If you read the article (broken ad software - phpAdsNew by the way :) - they said it wasn't the best, but it was probably getting there...

    How about utilizing the Peltier Effect - a.k.a. thermo electric cooling? =) Here is a little info here [thermoelectric.com]!
    Granted, they use a lot of power - I've seen from around 50W to 200W...

    Water cooling! I remember reading somewhere about Leufken - Gotta find a link... Just a sec... ;)
    Here it is! [leufkentechnologies.com] - Leufken Technologies - They got both watercooling and thermoelectric cooling, regular fans and heatsinks :)

    I myself is using a twin cooler (CoolTium) for my Athlon 900 - but it is SOOOOOOOOOO noisy!
    • How about utilizing the Peltier Effect - a.k.a. thermo electric cooling?

      You still have to get rid of the heat somehow - and thus the peltiers come with bulky radiators plus noisy fans themselves.
      As a bonus, you also have to handle somehow the condensation problem - the peltiers being able to refrigerate (or at least to go down to pretty low temperatures, close to zero Celsius).

      So, it's a promising technology, but it's not ready yet.
  • We allready use air-cooling for our CPUs. A radiator is the next logical step in cooling. It's a simple matter of efficiently moving heat arround. Something that car manufacturers have been doing for ages with good success.

  • Anyone else notice that the graphic on page 2 that shows the processor under load is messed up? The coloration for the MC462+delta and zen radiator are swapped. This graph shows the Zen as the worst of the coolers.
  • There was work done by Hamurgen and Fitch at DEC where they experimented with using heat pipe technology to cool chips way back in 1992.

    They needed a liquid with a high heat of vaporization, and a boiling point in the 30-50C range. They tried mixtures of water and alcohol, but settled on just water, pumped down to 1/3 ATM.

    They went looking through the "steam tables" and found that nobody had ever looked at the sub-atmospheric range of pressures, and had to derive all of the thermodynamic properties themselves.

    It was pretty quiet, but made a funny little 'tick' noise right when it started boiling.

    More details at http://www.research.compaq.com/wrl/techreports/abs tracts/92.1.html
    and http://www.research.compaq.com/wrl/techreports/abs tracts/90.9.html

    -Jeff Bell
  • Just what I've been waiting for: A CPU cooling device that physically breaks my CPU. Sounds like instead of a review of the product, they should have just had a 1 paragraph summary in large bold letters warning people from buying this defective product. Giving it a review almost gives it legitimacy.
  • Old news? (Score:2, Interesting)

    by jmatlock ( 232136 )
    Uhm... my Dell Inspiron has a water tube cooled CPU, it links to a radiator/heatsink near the back of the machine... and I got it almost a year ago... this isn't really anything new and spectacular. Intel developed it to work with the M series of Pentium III's... it's even listed on their site under technology.

Never worry about theory as long as the machinery does what it's supposed to do. -- R. A. Heinlein