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The Fanless Spinning Heatsink
An anonymous reader writes "There's a fundamental flaw with fan-and-heatsink cooling systems: no matter how hard the fan blows, a boundary layer of motionless, highly-insulating air remains on the heatsink. You can increase the size of the heatsink and you can blow more air, but ultimately the boundary layer prevents the system from being efficient. But what if you did away with the fan? What if the heatsink itself rotated? Well, believe it or not, rotating the heat exchanger obliterates the boundary layer, removes the need for a fan, and it's so efficient that it can operate at low and very quiet speeds. That's exactly what the Air Bearing Heat Exchanger, developed by Jeff Koplow of the Sandia National Laboratories, has developed. It's even intrinsically immune to the build up of dust and detritus!"
I think a better description would be a heatsink that is a fan or probably more accurately an impeller but without the tube enclosure.
These comments are my own and do not necessarily reflect the views or opinions of my employer or colleagues...
Doesn't there still need to be a stationary connection to the rotating heatsink since the CPU is stationary? And if that's the case, how does this help prevent the boundary layer? Seems like one would still be able to form between the CPU surface the the rotating heatsink.
I'm no scientist, however, so I'm probably making a false assumption. But I am curious how this alleviates that boundary layer...
I think the distinction between a traditional fan + heatsink combo and what is described in the article is that the impeller blades are dissipating the heat instead of merely blowing cooler air over the fins of a stationary heatsink.
These comments are my own and do not necessarily reflect the views or opinions of my employer or colleagues...
But think of all the homeless Dust puppies!!!
have you no shame?
I meant singular impeller not plural impellers. For those who don't read the article there is only one moving impeller.
These comments are my own and do not necessarily reflect the views or opinions of my employer or colleagues...
You sound angry. At thermodynamics.
Read The Fucking Article, shithead.
"This post is an artistic work of fiction and falsehood. Only a fool would take anything posted here as fact."
Lazy AC that wants to be spoon fed information.
Go home and change your diaper.
Some of what I say is fact, some is conjecture, the rest I'm just blowing out my ass...you guess.
I mostly agree but, I do have to point out... fans ARE pretty resistent to dust....in compairson to stationary parts near fans (like a traditional heat sink). While fan blades to accumulate dust, it happens much more slowly than the stationary parts near them.
A notable exception do seem to be ceiling fans, but they tend to be off much of the time and sit stationary and horizontal.
"I opened my eyes, and everything went dark again"
I think he just had an exothermic reaction.
yes. the spinning heat sink is attached to a spinning cpu, which is in turn attached to a spinning motherboard mounted to a spinning case. these are only available in funhouses btw.
The stories and info posted here are artistic works of fiction and falsehood.
Only fools would take it as fact.
This is all explained in the article and PDF.
Don't come here and start mouthing off like you know what you're talking about when you clearly are too lazy to get past the summary and expect everyone else to do the work explaining it for you. You must be an MBA graduate.
Some of what I say is fact, some is conjecture, the rest I'm just blowing out my ass...you guess.
You sir, need a hug. It's a pretty good article.
you thought wrong, they use standard box fans or squirrel cages
*Man* you read and analysed those 44 pages of maths quickly.
Personally I think this is a neat concept and would like to see some how these pan out in the real world. While there's nothing wrong with being skeptical by any means there seems to be some merit behind this. I'm particularly curious to see how this would perform in an HVAC system.
Regarding your question about bearings conducting heat - I was wondering the same question. I wonder if there's a way to make bearings specifically for this application with heat transfer in mind while still providing decent performance.
Well - yes.
You can avoid dust in that manner.
But only if you wind up the fan speed to several tens of thousands of RPM, and make them sound like your case is about to explode.
And also - read the article - the heat is transferred by the conductive fan rotating over a thermal plate with a .001" clearance.
This actively massively stirred air has fairly low thermal resistance.
I note the pressure guage next to the device.
This is presumably connected to a large compressor, providing reasonable rates of high pressure air, as you need for air bearings.
The average PC however doesn't actually have this.
That's exactly what the Air Bearing Heat Exchanger, developed by Jeff Koplow of the Sandia National Laboratories, has developed.
So I get it was not Jeff Koplow who developed it, but the Air Bearing Heat Exchanger did develop it. The Air Bearing Heat Exchanger in turn was developed by Jeff Koplow.
Oh, and BTW the link was missing a PDF warning.
The Tao of math: The numbers you can count are not the real numbers.
Comment removed based on user account deletion
If you read the PDF article, it says it works like an air-hockey puck or hard-drive platter, there's an extremely thin layer of air between the spinning surface which is under high shear which is conducive to heat conductivity. The PDF goes on to explain that this dramatically reduces the size of the boundary layer, not eliminate it as the summary says (since this isn't even logical what I remember of my fluids class). I didn't read the whole thing but I think it's the fact that the heat sink blades themselves are spinning at very high speeds, rather than having dirty air blown on them, that prevents dust build-up.
... made from the hooves of a unicorn.
Godaddy is a scam and a ripoff.
More to the point, the boundary layer shear is what enables this concept to work at all
Gamingmuseum.com: Give your 3D accelerator a rest.
Well this idea isn't new at all. Back in the 1910's aircraft engineers were trying to produce engines that could be cooled without heavy water jackets and radiator cooling systems. Putting cooling fins around the engine cylinders and block to let the passing air cool the engine worked, but not well enough given the state of metallurgy at the time. One solution was a rotating radial engine. In this configuration the crankshaft of the engine was bolted to the firewall and the block spun around with the crankcase and cylinders. The prop was bolted to the block. These rotary engines were cooled by spinning the engine. Some compromises resulted, the oil system was a non-recycling system with some oil being burned and the rest lost with the exhaust. A vegetable based oil was used (which had a laxative effect on the pilot!). Many of the aircraft of WWI used these rotary engines, including the famous Tri-Plane of the Red Baron.
Some of us had to read much more than 44 pages as we studied fluid dynamics in college. Apparently, there are rules for such things in this universe with no known exceptions.
The article is bull feces.
+1 sweetness factor, such a rare moment in /. land.
Life is a great ride, the vehicle doesn't matter
IANAFD but it would seem intuitive that moving an object at velocity X through air is the same (from the object's POV) as moving air at the same velocity[1] over the stationary object.
Otherwise wind tunnels would be a total waste of time.
[1] In the opposite direction, so -X, to be pedantic.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Do airplanes exert centripetal forces on the surfaces exposed to the moving air?
That would be a sweet airplane ride!
I think the better analogy would be to prove that the propellers on the planes still have boundary layers.
I would imagine replacing the 0.0254 mm of air with a ferrofluidic seal would increase the efficiency even further. A chip is not damaged by a permanent magnet and since the RPM is low it will not require a very strong magnet. The seal would be a good thermal conductor (somewhere around thermal paste).
Well, I might have a way, but it only works on a semi spherical planet in a vacuum.
I've read the paper and what you said is just silly, not insightful. The heat sink is separated from the base plate by a layer of air on the order of 1E-5m thick. This layer of air experiences large shear stress that keeps its thermal resistance low. It's basically an air bearing for the spinning heat sink. The stackup is thus:
1. CPU
2. Disk-shaped base plate
3. Air gap
4. Heat sink impeller
The major difference is that in normal coolers, fan has no heat dissipating function at al. There's no functional heat flow through the fan. In this design, the fan is the heatsink: heat does flow through it, and that's what makes it work so well.
From what I can tell, it's a truly revolutionary device. It has 5-10x lower thermal resistance than regular coolers, consumes ~5x less power than coolers of same capacity, and generates less acoustic noise to boot (it wasn't quantified, though). Ah, and also it doesn't get fouled by dust: ever notice how in usual CPU coolers the fan is usually clean or just sprinked with dust, when the heatsink is pretty much plugged with dust? In this device, the heatsink spins, so it stays clean, just like a fan would.
Whoever commercializes this for the HVAC market will be financially set, as in "playboy mansion" financially set :)
A successful API design takes a mixture of software design and pedagogy.
I'm curious to see this applied to a consumer CPU fan. Of course it will have to undergo some testing. It may be dust resistant but I don't know if it is Cheetos resistant which it needs to be for your average slashdotter. ;)
Well, there's spam egg sausage and spam, that's not got much spam in it.
it's a truly revolutionary device
haha! Excellent pun.
SJW n. One who posts facts.
LOL yes I forgot about that part
It's only "rightly so" if the summary accurately summarized the article. It doesn't. He didn't read it he just read the summary and wanted to post fast for physics cred.
And that's the saddest part of all. *sigh*
Someone posted it above. The actual article says it doesn't get rid of the boundary layer just significantly reduces it. He calls BS that the boundary layer is eliminated but the article doesn't say that only the summary does.
You're wrong.
Basically, the layer of air between the thermal spreader (base plate) and the impeller if very thin and very turbulent, because it is 'grinded' between the the impeller and the base plate. That actually makes it a very good heat conductor.
It's explained very well in the Sandia Labs paper. Seems like a very plausible and good design.
assignment != equality != identity
I like the "protective wire mesh container". Tell me it's not an office trash can.
Look silly, proof is in the pudding. Off-the-shelf CPU coolers have about 0.8C/W thermal resistances, this thing has demonstrated 0.2C/W in version 1 prototype, and version 2 is estimated to lower it to 0.1C/W.
How well do bearings conduct heat?
An air bearing? Very fucking well. So much so that its thermal resistance is an order of magnitude lower than the thermal resistance of the heatsink-to-air!
A successful API design takes a mixture of software design and pedagogy.
I thought a long standing goal of PC manufacturers was to do away with moving parts. I dont think fans will go away anytime soon as long as they are cheap to replace. From the comments hear I'd assume this heatsink spins on a platter essentially taking the place of the fan. What do you do when it fails? Can you replace it for less than $10?
Wow. Maybe Sandia should have just given you a call instead of all that research since you have all the answers.
No, turbulence mitigates the boundary layer problem, but does not remove it. This approach apparently, while not removing it completely, reduces it to the point where it's impact on the efficiency of the heat exchanger is negligible.
Sometimes the light at the end of the tunnel is the headlight of an oncoming train.
Ceiling fans also usually operate at very low speeds compared other fans...
While an entertaining post, one could speculate that building a spinning computer should not actually be that hard these days. You probably couldn't use spinning hard drives but SSD should work fine. Power could easily be supplied with some bushings. The hardest part would be video out, but I think there are high speed wireless video solutions. If not, you may be able to get away with bushings for this as well but your contact area has to be pretty consistent. The rest of the system could be wireless (keyboard, mouse, etc.)
Every time I start to have faith in humanity, I ruin it by driving to work between 7 and 8 am.
This story is pure bullshit.
Airplanes have boundary layers attached in flight.
All you need to do to a heat-sink is rough up the surface enough that the boundary layer is turbulent. It's not like drag is an issue.
The first point in favor of this heat-sink is pure bullshit. Want to bet everything else is also bullshit.
How well do bearings conduct heat?
WTF happened to /.
There are two significant differences between wings and heat sinks. Firstly, wings are moving compared to the ambient air, and heat sinks are not. Secondly, for aircraft the boundary layer is a good thing, and designers try and make is stick as much as possible (though the do put in widgets to ensure that when it breaks off and goes turbulent, it does so progressively, not suddenly). Roughening, on the appropriate scale, is used to increase boundary layer adhesion - the "golf-ball" effect. It is also being tried on ships, especially racing yachts (the "shark-skin" effect). The desired effect is the exact opposite to that here: wings want boundary layers, heat sinks don't.
Consciousness is an illusion caused by an excess of self consciousness.
I know this is /., but the lack of TFA reading comprehension for this article is crazy even for slashdot standards.
The PDF never claims that the spinning heat sink eliminates the boundary layer. They only claim that spinning the heat sink reduces the boundary layer thickness by several orders of magnitude. And it makes sense, as the speed of air over the impeller blades moving at several thousand RPM is quite a bit faster than the speed of air that can be pushed over a static heat sink by a traditional fan. The faster the airflow, the smaller the boundary layer. The only way to get air moving that fast over a static heat sink is with a jet, and establishing such a jet in a computer enclosure environment exceeds reasonable power requirements.
I think the better analogy would be to prove that the propellers on the planes still have boundary layers.
they do. since in the real viscous world, you can't have air moving directly on a surface. the air has to transition to whatever the speed of the surface is over some distance (however small). this is what we call a boundary layer.
Good Lord. Have your psychiatrist adjust your dosage.
TL;DR version: Stationary heat spreader surface on top of the IC. Teensy tiny air gap, small enough to permit heat transfer while functioning as an air bearing between heat spreader and... the next part, a heat-absorbing rotary impeller which pulls heat through the air gap into its fins, which are in turn cooled by air flow caused by centrifugal acceleration of the air through the rotating impeller assembly (squirrel-cage-fan style).
I'm not gonna pretend that there's no boundary-layer effect over the impeller blade surfaces, but I expect it'll be less than the effect caused by the common "push air down into the cooler and have it decelerate and turn 90 degrees to exit" cooler. Flow-through coolers would be more efficient than that, but air still has to decelerate through the cooler, whereas this impeller cooler makes the air accelerate during the cooling action. That might make a difference.
How well do bearings conduct heat?
The generic answer is "depends on thickness of air bearing surface (i.e., how big of an air gap), coverage area of bearing surface (i.e., is the heat spreader the size of the entire impeller, or just the small central portion of it), and the rotational speed of the rotating part on the other side of the gap -- moderate rotation speeds, in the 2k to 10krpm range, make the air in the gap turbulent and sheared rather than laminar, forcing mixing and heat transfer.
WTF happened to /.
Well, in this case, an actual scientific research article of relatively high coolness and technical merit leaked past the editors. I understand how this could be upsetting to most slashbots, given the novelty and rarity of this type of thing. Certainly, t
Welcome to the Panopticon. Used to be a prison, now it's your home.
*Man* you read and analysed those 44 pages of maths quickly.
I skimmed them.
It seemed to very carefully avoid the issue of the bearing's heat conduction ability while explaining how spinning a heatsink does reduce its thermal resistance vs merely blowing air upon it. So you decrease the resistance at one end while ignoring the increase at the other. Hmm.
The other mystery is the straw dog of cheap and easy to machine heatsink designs (you've all seen them) have moderately bad boundary layer problems, so rather than a more elaborately modeled and machined heatsink design, or even more simply, a larger heatsink, the solution is a very complicated, hard to model, and hard to machine rotating heatsink. So, why not just put the hydrodynamic engineering hours and CNC machining hours into a GOOD passive sink that might work just as well? Or invest in a couple more dollars of aluminum, or skip it all and go for broke with waterblocks. Who knows?
Is there a middle ground for this design to live in between cheap and easy and inefficient non-moving sinks and much higher performance (and cost) waterblocks? I'm guessing, no. Not in any electronic system I've worked on (not just computers, but high power RF amps, high power audio, high power VFDs, etc)
The other problem is it makes for a more brittle design. Now you can usually shut down a system automatically when the cooling system stops, due to thermal mass, limited natural convection cooling, etc. With this, it'll be smaller and lighter, can you shut down in time to avoid frying the CPU (physically) or crashing the filesystem? Its going to make OTHER parts of the system design more complex, not just the cooling system.
Cool engineering (pun intended) but I'm unimpressed from an economic standpoint. It will probably cost more than the alternatives. Unless you're just trying to avoid a patent or whatever.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
But in a conventional system, the air is moving fastest over the cool fan, and much slower over the hot heat sink - in fact, very slowly over the last fraction of a millimetre. In the system, the air is moving fastest over the hot fan.
Consciousness is an illusion caused by an excess of self consciousness.
Except that when you rotate you are not only moving, you are accelerating.
Rethinking email
In these "old" engines, the cooling block itself did not move, rather the engine it was attached to moved. The equivalent would be for an entire PC to spin in for radiators attacked to it to be cooled. This would be highly inconvenient for any cat owners as well as make it even harder to plugin that USB cable.
MMO Quests are like orgasms:
You may solo them, I prefer them in a group.
Don't some lawn mowers have heat sinks like this that spin atop the engine?
Anyway, I'm much more interested in the air conditioner applications of this than electronics use. I like the idea of a quieter, 30% more efficient air conditioner/heat pump. Great article.
Proverbs 21:19
wonder if the barrier is caused by the constant, unidirectional flow of air from a fan?
while it's hardly an efficient/practical design, would you achieve the same efficiency if you moved a fan around the heat sink?
Also, a filter on the intake seems a simpler solution to fouling.
Soon at the heart of every computer there's a metal fan.
yea filters get clogged, and I really dont by the immunity thing, yes it may not get compacted tween a fan and the top of a heat sink but it seems like the fins of this thing would be just as easy to clog since your passing dirty fluid tween small spaces
With this, it'll be smaller and lighter, can you shut down in time to avoid frying the CPU (physically)
I seem to remember Pentium 4 CPUs using a scheme like this: When the temperature exceeds one threshold, the "Thermal Monitor" puts the core to sleep for a few microseconds every microsecond. When it exceeds a higher threshold, the CPU halts.
or crashing the filesystem?
A reliable file system has to survive loss of mains power anyway.
We don't need a lot of big government creating new technology and improving our energy consumption!
Democracy Now! - your daily, uncensored, corporate-free
It still amazes me how many engineers on this site immediately dismiss the work of another engineer or scientist based on a summary by the media. I would have thought that smart people would realize that it is the regurgitators (I refuse to call them journalists) that don't know what they are talking about 90% of the time, not their fellow engineers.
(Emphasis added.)
How well do bearings conduct heat?
Again, the technical document makes it clear that the rotating heat sink is not coupled via a bearing to the surface it's cooling. Rather there is a very thin layer of air separating them. Naively one might think that this layer of air (generally a poor heat conductor) would become limiting, and there would be poor heat transfer from the hot plate to the rotating heat sink. However they address this:
So, basically by keeping the air gap very thin (30 microns), and by substantially shearing/mixing this thin air disk, its thermal conductivity can be sufficient to transfer heat up into the rotating fins. Overall a rather clever design.
WTF happened to /.
I agree a lot of junk gets posted to Slashdot. But in this case, a link was actually provided to a good technical document that answers many questions, provides schematics, and shows graphs of various performance measures.
They do not avoid the bearings heat conduction ability:
As shown later in Figure 18, this air-filled
thermal interface has very low thermal resistance and is in no way a limiting factor to device
performance; its cross sectional area is large relative to its thickness, and because the air that
occupies the gap region is violently sheared between the lower surface (stationary) and the
upper surface (rotating at several thousand rpm). The convective mixing provided by this 11
shearing effect provides a several-fold increase in thermal conductivity of the air in the gap
region.
I see no reason why this should not be subject to cost engineering like any other component. Yes, they machined their prototype our of solid aluminium on a CNC machine. But they are not production engineers. It would seem to me that, as one-moving-part system, this should be subject to manufacturing optimisation over two or three years to be very competitive with equivalent air cooling systems.
Your point about the design being more brittle is relevant: failure of the drive motor will lead to serious overheat in a very short time.
Consciousness is an illusion caused by an excess of self consciousness.
This is presumably connected to a large compressor, providing reasonable rates of high pressure air, as you need for air bearings.
The average PC however doesn't actually have this.
Now you need to cool the big air compressor, which likely requires the whole air bearing arrangement. No problemo, you supply a little air compressor to cool the big air compressor. Now you need to cool the little air compressor, oh, its turtles all the way down, here.
The other problem is air bearings are real cool in a controlled system or for lab experiments, but in the real world fulla slugs of condensate water and compressor oil contamination, they're no walk in the park. As you've probably noticed the lack of air bearings around your house and work. Come up with a way to make air bearings "ready for prime time" and there's plenty of other exciting applications beyond just making smaller CPU heatsinks. Kind of like those spaceship designs that begin with "first, assume fusion reactors and warp drives. Then the rest is easy"
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
The heatsink + fan approach has one boundary layer on the heatsink, this approach creates two:
1. On the surface of the rotating heat sink
2. On the air cushion where the rotating heat sink "sits" on
What makes sense is to use energy efficient systems, not using any CPU-/GPU-fans and use a large and slowly rotating fan moving the air through all of the case and go for standard heatsinks on your chips. Voila: quiet, energy efficient and efficient at the same time.
This is awesome. It appears to be using similar principles and design to Tesla's turbine! (From wikipedia, which doesn't have a good picture of the innards) "The Tesla turbine is a bladeless centripetal flow turbine patented by Nikola Tesla in 1913. It is referred to as a bladeless turbine because it uses the boundary layer effect and not a fluid impinging upon the blades as in a conventional turbine"
"Sometimes a woman is a kind of religion, she can save your soul & set you free from all your sins" - Bad Examples
if you studied fluid dynamics in college, and stopped at the article before reading the PDF, your degree is bull feces. It's an extremetech article about actual technology, with physics involved in the explanation. what did you expect?
and the PDF accounts for that.
Look silly, proof is in the pudding. Off-the-shelf CPU coolers have about 0.8C/W thermal resistances, this thing has demonstrated 0.2C/W in version 1 prototype, and version 2 is estimated to lower it to 0.1C/W.
Almost, but not quite, as good as an off the shelf waterblock system now, maybe as good as an excellent waterblock system in the future, maybe, with some luck, in the lab.
Of if you want no moving parts, about as good as a poor heat pipe system, or ten to a hundred times worse than a truly excellent heat pipe system.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
In the case of an aircraft engine, the air cooled cylinders have a short thermal path to the air from the heat source. The problem with cpu cooling is mainly the long thermal path which makes it hard to get moving air down in the fins.
Finally, you might be amused to know that the lubricant (castor oil) was simply better than any mineral oil up until the 1930s. The Castrol oil company derived its name from it. And the solution of the pilots to the laxative problem was to drink whisky. It's not surprising that WW1 pilots had an operation life expectancy of a few hours.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
.. it seems like a great invention, trully ground-breaking if it works. All we have to do now is wait for the patent wars to be over (suddenly $BigCorp and $PatentTroll "discover that this infringes on their innovations somehow and some such"), and by 2054 this will be a commonplace in cooling.
Now I wander if the guy was under contract- if he was, he will probably get nothing but his salary out of it. One of my friends is family with the guy that invented the dictionary in cellphones; but since he was under contract he got nothing more than that month's paycheck ..
The three laws of thermodynamics:(1) You can't win. (2) You can't break even. (3) You can't even quit.
That's it, really. Small IC engines are usually air cooled using a ducted fan. My rotavator has one. As I note in a post above, IC engines don't really have the problem because the path from heat to sink is short and the power density is quite low, and the main benefit of well designed fan cooling is that the cooling is even around the cylinder. The fin depth on a Honda 50cc engine is less than that on many CPU heatsinks.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
And wouldn't the friction of the thing spinning generate heat as well? I'll admit i just looked at the pics but heatsink compound is made for heat transfer NOT lubrication so I don't see how this would be such a great improvement, not to mention having it spin right on top of the CPU would have me worried about it putting sideways pull on the pins, as anyone who has built boxes knows those pins are teeny tiny and don't take much to bend so if the lubricant you used started to get sticky I could see this thing slowly but surely causing problems with the pins.
So unless someone can explain how they've done away with friction and the risk of stress on the pins I have to vote meh. And while this might have been helpful in the days of the P4, aka space heater in a box, at least with modern CPUs if anything power has been going pretty steadily downward. I know I have to slam the new AMD quads pretty damned hard to get the fan to crank up and even then they rarely reach above 130f, and that is with all four cores pegged. For day to day usage they tend to stay like mine is now at 94f with the case fan being the only real fan noise.
ACs don't waste your time replying, your posts are never seen by me.
It sounds like it's still in the research phase, which means it's not a viable commercial product yet. All the things you describe would need to be solved in order for it to be commercially viable. But the concept is novel, and deserves credit for what it is.
Whether this will ultimately end up being a replacement or a competitor in the current cooling systems market will be a matter of whether these problems can or need to ultimately be solved. Since this phase of the research deals only with the viability of the new design, I suspect it will be.
"If a nation expects to be ignorant and free in a state of civilization, it expects what never was and never will be."
WTF happened to /.
It became popular, which widened the bell curve and probably lowered the average IQ (not by a lot, let's not flatter ourselves unnecessarily). We have a couple of capital-T Trolls here, APK and MichaelKristopeit, and it's always been unclear what the role of the editor is supposed to be since they don't appear to do shit. The GNAA contingent seems to have died down. Neither of us are submitting articles, it seems, and likely not participating in the firehose (there being no real incentive to do so).
Seems like business as usual to me. A change in management couldn't hurt: you know, maybe someone interested in promoting the site, improving the quality, and completely redesigning the site to support unicode and generate valid html.
More on topic, turbulence is indeed the right answer to this "problem". Thanks for posting, +1 Informative.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
If I understand what is being said:
In this set up we still have a fan of sorts, though if it stops rotating it doesn't afford the same advantage as a heat-sink + fan set up. It also means you need to have spinning device, no matter the heat level of the CPU, which means that you will still have a certain noise level.
I am not a fluid mechanics engineer, so bare with me as I as this question: If we kept the traditional heat sink, possibly changed its shape and instead got the fan to rotate around the outside of the heat sink, so air is drawn across, would that help make a difference? I am also wonder whether making CPU housing circular would help change anything? I am thinking on the run here, so there are probably some stupid ideas here.
Jumpstart the tartan drive.
Particularly, the bottom part of page 42. I guess that was the answer to the ultimate question...
I did read the BS pdf.
Difference is that fans don't really need to be dust free to work, they still move air even when dusty.
This new concept might be vulnerable to the surface of the plate getting scratched up, or even fail catastrophically if something gets wedged into the gap. It will be interesting how it works out in practice, especially in uncontrolled air conditioning applications. Throw a handful of bugs and dirt on it, or rain, or even hail and see how it works compared to an current design.
It appears to be using similar principles and design to Tesla's turbine!
No, that's quite different. This thing has blades. It's a centrifugal pump for air.
I'll believe that when I see some empirical evidence. Seems like they've just said "well it spins; of course it won't get dust." My current fan spins, and the fanblade is covered with the stuff. Static attraction overcomes the motion easily.
"The Sandia Cooler may also be the technology that smashes down the “Thermal Brick Wall” that is preventing computer chips from moving beyond 3GHz."
Sorry, we've got CPUs hitting 4+ GHz on stock air cooling without your specialized heatsink. Your thermal brick wall doesn't exist and hasn't for quite some time.
We also have mesophase carbon pitch heatsinks hitting 1,000wmk, 4x better than copper.
Fire the article writer, as it's clear they've had their head in the tech sand of yesteryear.
Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
The point is that the air is travelling fastest at the surface of the fan, slows as it passes through intervening space, and slowest when it strikes a fixed object, the heat sink - which is where its speed is needed. When the medium speed airflow hits the unmoving heat sink, a boundary layer builds up, making the effective speed for the last millimetre negligible. No, making the fan move would not help much; it is the fact that the cold object is moving fastest and the hot object moving slowest which makes the current system inefficient. This design makes the hot object move fast relative to the surrounding air.
Consciousness is an illusion caused by an excess of self consciousness.
Although Figure 10 of the article shows and labels the pressure regulator, gauge, manifolds, etc., those are there to create an air bearing with a well-defined gap that they use for characterization and calibration. In practice, none of that claptrap is necessary: the air layer will be created entirely by the rotation of the fan disc. This is more or less the same as the tiny layer of air that is created under the read/write head of a harddrive.
At 5,000 RPM what is going ot really determine noise is the force of blades against air at a given RPM - given the shown shape of this design, it looks like a modified slim blower fan. These run much quieter than your typical axial fan.
Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
From TFA, highlighted for your convenience...
The cooler consists of a static metal baseplate, which is connected to the CPU, GPU, or other hot object , and a finned, rotating heat exchanger that are cushioned by a thin (0.001-inch) layer of air. As the metal blades spin, centrifugal force kicks up the air and throws it up and outwards, much like an impeller, creating a cooling effect.
...it's a truly revolutionary device.
Maybe... about hundred years ago...
For justice, we must go to Don Corleone
Apparently you've never had to work on the box of someone who has cats. Trust me, the power of cat fur completely overwhelms your pitiful fan, no matter how many filters you put in the damned thing. I swear it is like cat fur is sentient and has the same 'fuck you" attitude of its former owner and seeks out things that will piss you off, the way a cat scratches on the curtains.
As for TFA I've gotten a chance to skim the PDF ( a little too math heavy for an overview frankly) and i don't get what is gonna keep the CPU equivalent of a headcrash from occuring. After all we had HDD tech for a hell of a lot longer and we still suffer from headcrashes, not as often mind you but they do still happen. Now considering if you have a headcrash with this airgap it is bye bye CPU (or AC, or fridge) and so far I haven't found anything addressing this I am curious to see how he managed to eliminate this problem.
ACs don't waste your time replying, your posts are never seen by me.
The effect of the Sandia device is not to eliminate the boundary layer, as the article says, but to make it much thinner, as the PDF says. The thermal resistance of the boundary layer is approximately proportional to its thickness, so the heat transfer goes up by the same ratio. That moves the heat into the air between the impeller fins, which then proceeds to carry it overboard.
That's what is so impressive about this work. A spinning, finned heat sink isn't new. Combining it with a thermally efficient coupling to a stationary heat source is.
They came up with a helical groove design to maximize the radiating surface while also moving some air to create circulation. The dust free radiating surface heat exchange efficiency was so high, they needed to move very little air. So the final design has large moving surfaces with small grooves in them to move a little air. That is all.
The moving helical groove fan can not be scraping along the top of the IC chip. There is a gap. And if that gap is not well protected from dust, it will get there. May be they can come up with a seal and a fluid coupling? I am not sure.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
The bearing between the fan and the plate is a very small air gap. Because it's small, and because it's constantly being churned around, it's thermal resistance is low.
Because the movement fan part destroys the normal zone of still air around radiator fins it dissipates heat more quickly and efficiently.
The externally-driven air bearing was there for experimental control and convenience. In reality the airgap would be established solely by spinning the fan disc.
Air bearings are used in several awful environments. For instance, they are used extensively in high-speed, high-precision CNC mills: an environment filled with metal chips, splashing coolant, smoke fumes, etc.
I know its said a lot and should be common knowledge but I think it pays to stress it more strongly on occasion. This seems like an ideal time, READ THE FUCKING ARTICLE.
Several posts now, numerous mod points and dozens of follow ups all frankly making complete asses of themselves ironically complaining about how the IQ of /. has dropped while they make angry complaints and rants about the story that are fully addressed in the documentation.
and if you think that the fact that the summary screwed up is still a good sign of /. intelligence drop then you really need to look right back in the archives because bad summaries have been around on /. and virtually everywhere else pretty much from the beginning. Unsurprisingly the people posting the stories dont have total knowledge of the often fairly complex material posted and they screw it up good and proper on occasion. Which is probably why you should be judging the posts on the documents they link to and not the quickly thrown together summary by an admitted layman. Anything else is ironically a really stupid thing to do.
READ THE FUCKING ARTICLE.
(and no this doesnt mean the documentation is flawless but make commentary on that, not the summary, it will raise that intelligence level a lot of you are so eager to whine about.)
Anyone with an old oscillating fan can tell you that just because it moves doesn't make it 'immune' to dust. It may resist heavier buildup but it will end up just as coated eventually.
When a fan rotates, the air right on the blades doesn't move -- that's why fans get dirty over time, as dust gets caught in that region of barely moving air.
I'm not sure I see a big difference here between a heatsink that moves through air and a heatsink that has air move over it.
Man that is a long article. I didn't read every word, I skimmed it looking for what's important to most PC builders: the damn thing's thermal performance.
There are a lot of graphs, but I kept looking and couldn't find one that simply showed how well it performed in cooling compared to other devices.
Finally I found a tiny little graphic showing the prototype in a list with other HSFs. The result? I tiny improvement over most of the devices it was compared to. However, the article indicates that the first prototype had a sub-optimal design and they anticipate much greater improvements in version 2.
Maybe that's why they wrote this hugely dense report instead of just releasing a brief statement saying "we've kicked the ass of other HSFs". Maybe if their next version shows a significant improvement they will be able to do it, and then I'll give a crap.
My big concern is that now you have a large rotating mass with extremely tight tolerances. Those are some thick blades, likely to maintain pressure and prevent detachment from the suction side, so unless they're hollow inside, this thing will be fairly heavy. If you're using a laptop, now you have a couple hundred gram mass spinning at a couple thousand RPM, and you have to mount it robustly enough that you don't impact the base when you tip the laptop.
While this may be massively more efficient than existing static heatsinks, I find the claim of 7% power reduction country wide a bit dubious. On a desktop, you use a few watts to run fans on a machine that does ~75W idle, and hundreds of watts under load. On a home AC unit, you're looking at a 150W fan cooling a several kW compressor. For industrial units, you're usually talking evaporative cooling which does not suffer such boundary layer issues.
Further, this seems a fairly complex solution just for boundary layer management. Surely the whole of the aerospace industry couldn't have come up with an easier solution. Swiftech used to make a series of spiked coolers, where the cooling surface was what looked like a bunch of machine screws. High TKE means low separation, even around the back side of a cylinder, but it was noisy and needed a decent fan to drive it. You could use a roughened blade surface to increase turbulence, increase mixing, and preventing separation. You could use a curved fin like many existing circular coolers, so pressure gradient would keep the flow attached on at least one surface. You could use a wedge with the pointed side aimed upstream, to provide positive pressure on both sides.
+1 sweetness factor, such a rare moment in /. land.
Phah! What do you think this is, reddit???
in girum imus nocte et consumimur igni
The exception to this rule is lap top computers, where available electrical power is extremely limited. In this special case, CPU clock speeds and fan rotor speeds are reduced to conserve power, albeit at the expense of CPU performance. At these low fan speeds the residence time of air in the heat exchanger is greatly extended, resulting in much higher exhaust air temperatures.
I will create a sig when innovation restarts in the U.S.
Looks like I previously responded to the wrong comment.. Anyway, you're close..They did use to spin the whole engine back in the day
For justice, we must go to Don Corleone
Q: How many fanless spinning heatsinks does it take to change a lightbulb?
A: Just one. It stays put, and lets the CPU, PC (and attached world) revolve around it.
Why OpalCalc is the best Windows calc
It's even intrinsically immune to the build up of dust and detritus!
I seriously doubt that. Anyone who has repairs computers can tell you that even rapidly spinning fan blades can accumulate a thick coating of dust. Since this new device spins at "low and very quiet speeds", it's probably even less immune to dust.
Considering that you where having to have a heat sink already + a fan to move air over that surface area.
now you are removing the fan and increasing heat removal over a surface area - i wouldn't be surprised is the required weight wasn't less than an the current cooler needed.
please note that for the same amount of cooling they had a 4 times reduction in size.. i there was a good reduction in weight to go with it..
'...if only "Jumping to a Conclusion" was an event in the Olympics.'
This was my thought also; seems to me that a surface treatment to create turbulent flow would be far easier than this thing, even if it does work (and I have no reason to believe it doesn't). But without doing the math there's no way to know if that would work either.
Honestly, if you have a comp full of cat hair its because the owner is a dirty person and never vacuums or dusts.
Good-bye
another problem is that dust could get into that thin layer of air
I have no mod points, so I'll give you a high-five instead.
When this does make it to a commercially available product he'll probably be back claiming how it's not really newsworthy, and tell us about how this article from a long time ago, and how it's all been done before. /. just wouldn't be the same without the trolls.
Is 1563649 a prime number?
If it's anything like the fans I see, the blades end up dust coated but not dust choked. Dust beyond a certain level gets flung/blown away.
Whereas conventional heatsinks can end up dust choked.
The difference is that the air from the fan is moving linearly over the heat sink. With a spinning heat sink, the air is not going in a straight line from the heat sink's perspective.
Water in a computer is a PITA. Water cooling systems are hard to replace and can be difficult to deal with. Which is why very few stock machines use them.
My first thought looking at the linked paper was, "January 2010? Why hasn't this been all over the place if the results are so promising?"
But there could be lots of reasons for that. Just sort of popped out.
Another question that comes up is overall system efficiency. One advantage of the current fan + heat sink paradigm is that in addition to moving air across the heat sink, which is not terribly efficient, the fan also serves to mix the heated air around the heat sink with the larger reservoir of surrounding air. They don't really directly discuss it, but my impression is that their design would result in very little large-scale mixing; one of the efficiency advantages is that they aren't moving large amounts of air around. It seems that in a setting like a CPU cooler this might be a non-issue, as you would still presumably be using case fans to move air through the case (exchanging the reservoir); but in something like an air conditioning unit, it seems like it would become limited by convection for larger scale heat transfer - or require an external fan for air exchange.
Basically, my concern is that while this method might be very efficient in moving heat from the base plate to the air in the immediate vicinity, you would then have the problem of heat building up around it. Perhaps not an issue where you have a small-scale device open to a large, room-temperature environment (or where you already have something in place to move air around, like a computer case), but it seems like it could be an issue moving to something like a residential air conditioner.
Still, it appears to eliminate the boundary layer problem, so you could use a pretty efficient, large, slow-moving fan for air exchange - so probably more efficient than blowing high-speed air across a heat sink, but something that would need to be considered in a full implementation.
immune to dust
Let's just start with "NO" and go from there. Unless you've got a high grade low micron filter on the intake, air circulation is going to lead to dust collection. And then you have filters to replace. Neither solution has any business calling itself "immune" to the problem.
The article reads like a used car salesman trying to sell you a car based on all the wonderful "win/win" features it has, trying to ply a "reality distortion field" as the popular saying goes.
And unless it's using a sealed fluid bearing, that is going to get fouled eventually by dust too. That's what tends to take down cpu fans. Considering the comparatively low torque of such a system, it should come to a stop a lot sooner too.
And I never did see any justification on this "boundary layer" theory, and as to why the lack of a fan magically makes it disappear.
I work for the Department of Redundancy Department.
All of the gaming enthusiasts complaining that this is impractical for heatsink technology because it's too expensive, or that a simply larger passive heatsink could do just as well, are missing the whole point of this kind of research. Engineering is an optimization problem, and keeping the size/weight parameters the same while increasing efficiency is a victory any way you cut it. Sandia does a lot of weapons/aerospace research, so this may have immediate applications for them in computing environments where size/weight constraints are the limiting factor.
My mod points!!!!!!!! Where are they?
Yes but considering that the purpose of a heat sync is to dissipate heat rather than blow air, the point it mute. If the blades get coated, then heat dissipation is still reduced. I'm not saying it's not a better idea than current implementations, but they should at least be a bit realistic in their claims.
Are you telling us that the whole darn radial motor was rotating? Still, it's not exactly the same: in case of the radial motor, the source of heat would be rotating as well; here there is a major element that is absent in a radial motor with rotating cylinders. Namely, the heat-transferring air bearing. Of course, the combustion gases in an ICE do exchange heat with cylinder walls and piston. Yet, to make it truly equivalent to the new design, you'd need something like burning pistons that then exchange heat with gas, that then dump the heat into the cylinders.
A successful API design takes a mixture of software design and pedagogy.
I find the claim of 7% power reduction country wide a bit dubious. On a desktop, you use a few watts to run fans on a machine that does ~75W idle, and hundreds of watts under load. On a home AC unit, you're looking at a 150W fan cooling a several kW compressor.
On a 2U server, I've measured it: the fans, running on a hot day when the office is at ~26C, are pulling about 50W. Noisy as hell, too.
The major win here is a combination of things: lower motor power consumption and higher thermal efficiency of the thermodynamic cycle in the HVAC system, as the heatsink thermal resistance is down by a major factor. In a home AC unit, the thermal resistance of the heatsink (internal and external!) figures directly in the equation for the efficiency of the unit!
A successful API design takes a mixture of software design and pedagogy.
While an entertaining post, one could speculate that building a spinning computer should not actually be that hard these days. You probably couldn't use spinning hard drives but SSD should work fine. Power could easily be supplied with some bushings. The hardest part would be video out, but I think there are high speed wireless video solutions. If not, you may be able to get away with bushings for this as well but your contact area has to be pretty consistent. The rest of the system could be wireless (keyboard, mouse, etc.)
A dove prism http://en.wikipedia.org/wiki/Dove_prism turning at half case speed will do it.
The experiment came to grief when the cat-5 cables to the cable modem were first untwisted then reverse twisted , and finally made a mess of the modem.
> it's a truly revolutionary device Sorry, can you clarify if the pun is between truly and revolutionary? or between revolutionary and device?
The Farnsworth Heatsink is much better. The heatsink stays still while the universe spins around it.
revolutionary...spins
I swear to God...I swear to God! That is NOT how you treat your human!
In this device, the heatsink spins, so it stays clean, just like a fan would.
fan bldes get dusty too.
If there is rain, or hail within your PC case, then you are already well beyond the operating conditions that any of this stuff is designed for.... certainly surviving rain or hail speaks wonders of its design but, failin gunder those conditions is hardly indicative of how it will perform in an expected environment.
"I opened my eyes, and everything went dark again"
we immediately dismiss claims made that are impossible by the laws of this universe. For instance, using part of your car engine's power output to crack water, then injecting the hydrogen / oxygen mix into the engine and claiming you have invented a system that lets your car run on water. Or claiming that a car powered by compressed air is immensely more efficient than liquid fossil fuels. This falls into such a category.
It is reduced but I'd wager that even coated fan blades are more efficient than a solid block of non heat conducting material, i.e. the dust caked onto the now solid heat sink. There's 'zero' airflow over the surface if you can't get to the surface.
The fans are still pushing air over the surface.
People in cars cause accidents....accidents in cars cause people
You probably couldn't use spinning hard drives but SSD should work fine.
This problem is solved by keeping the platters stationary as the case spins about them.
you dont understand. they go with my monster cables.
Drop the "micro" and what you've said should be very obvious.
I realized what I had written after I had clicked Submit. On the actual P4, the Thermal Monitor sleeps are as long as the wakes. I apologize for any confusion.
I initially had the exact same objection. However, this guy summed up the principle pretty well.
Executive Summary: There is still a boundary layer, but it's very, very thin -- much thinner than the boundary layer on the skin of an airplane. Because it is so thin, but has a very large surface area (think "sheet of paper") it still conducts a rather large quantity of heat away from the heat source, allowing much more efficient cooling than a conventional heatsink/fan combo.
MCSE? No, sir...I don't do Windows. Yes, I am an idealist. What's your point?
And I never did see any justification on this "boundary layer" theory, and as to why the lack of a fan magically makes it disappear.
It's basic aerodynamic theory.
Except that the claim that it eliminates the boundary layer was made by the regurgitator, not the paper. Here is what the paper claims:
The "Air Bearing Heat Exchanger" provides a several-fold reduction in boundary layer thickness, intrinsic immunity to heat sink fouling, and drastic reductions in noise.
That is not an impossible claim and they have data to back it up.
Again the problem is assuming that the claims made by Extreme Tech accurately represent the claims made by the researchers, when in reality the media almost never reports on engineering and science correctly.
I wonder how jostling of the PC case might affect this 'bearing'? Is it possible that the spinning disc would then impact the static metal base plate?
Seems like this concept would already have been dealt with via spinning hard disk platters, but those don't weigh nearly as much as a heat sink and are segmented out specially with shock absorbers in the HD enclosure.
People in cars cause accidents....accidents in cars cause people
Rather than a narrow air gap which might be delicate, I wonder if filling the space between the stationary and rotating parts of the heat sink with oil or even water would be better. Air has a thermal conductivity of .024. Oil and water have thermal conductivities roughly an order of magnitude greater. An objection to this idea would be the need for a low friction seal around the circumference of the unit but perhaps such low friction seals exist.
That "boundary layer" theory is well justified by models and experiments. The lack of a fan does not make it disapear, but rotating the heat sink does make it smaller.
About dust, it only accumulates over a hight speed rotating surface (where the air speed is increasing) up to a certain amount. That amount is certainly way lower than the dust that accumulates at a static place where the air speed drops. Immune do dust is a justfied simplification, altough a bit over confident.
Also, I completely agree with your point about the dust accumulating at the gap. That device won't last for long at the real world.
Rethinking email
Does it work when it's vertical (i.e. axis of rotation is horizontal)? It's been a long, long time since my desktop was actually on my desk rather than stood beside it.
Disclaimer: I only skimmed the PDF, I didn't RTFA at all.
If God forks the Universe every time you roll a die, he'd better have a damned good memory.
LOL. I was going to say that a spinning computer would give you the same effect, but you more or less got it.
#1. No didn't RTFA.
I can just see a 500g serrated chunk of copper spinning at 2500 RPM inside a framework of delicate electronics!
I hope you mount it exactly right, be a shame if that thing got the speed wobbles and physically destroys everything in your PC case!
But then, why not "glue" (as in attach with brackets and thermal paste) a heatsink with FLAT SURFACE on top of the die, and THEN "mount" the impeller on top of it - at a distance of the mentioned 1 micron, I mean?
I only proposed that because since air is one of the worst thermoconducters ever, and heatsinks and thermal paste are made for thermoconduction, principally, with the same proposed novel design the guy outperforms his own design, had it been applied directly to the CPU die, the area of which varies with CPU model etc - i.e. I am betting that with a CPU dissipating 65W like modern desktop Intel CPUs do, from an area of around 1cm2, I would guess that even with 1 micron air gap it would still be hard to dissipate the heat coming from that area, and/or require more impeller revolutions and thus contribute to more noise and earlier malfuncion / increased wear-and-tear.
Am I making sense, or have I just invented all of what I said? :)
I wonder how TFA might have covered this subject...
That's all well and good but what do you do to get rid of the heat in the fluid besides run it through a radiator with a fan on it? But wait! If we use one of these spinning heat sinks on the other end of the liquid cooling system, it will be more efficient. But then it's still more efficient to use liquid so let's immerse that one. Crap. We need another radiator. Hey! Let's use one of those spinning heat sinks...
iMacs and MacBooks use radial fans and you could say this is a radial fan too. However in this case the heatsink is it self the fan while macs use the normal fan with separate heatsink construction. BTW there are also PC notebooks and desktops with radial fans. Radial fans are in general quieter and are much better at building pressure so they are much better at pushing air through a heatsink. However they are more expensive.
"WTF happened to /."
nothing. It has always had articles of complete BS.
Why people think it was better years ago is beyond me.
The Kruger Dunning explains most post on
"...when in reality the media almost never reports on engineering and science correctly."
This would be put on the top over every article in the media that talks about and science.
or maybe this on the front page:
"...when in reality the media almost never reports correctly."
The Kruger Dunning explains most post on
Show me a single water system that has NO moving parts.. just one.
The Kruger Dunning explains most post on
I guess I'm the stupid one here, but I don't understand the basic premise. Can someone please explain exactly what this "boundary layer" of motionless air is on a regular heatsink/fan? Why/how does it form and exactly how big of a problem is it really? I am just not understanding how there can be any motionless air unless there are some eddies formed by the fins or some such. Help! Thanks.
Yes propellers still have boundary layers. I would have thought that was clear, but should have accounted for the denseness of /. these days.
You often scratch a line on the front of a model airplane propeller to trip the boundary layer, turning it from laminar to turbulent (where exactly you put the scratch is beyond the scope of this post). They also put turbulators (those little fins you often see on the engine cowl and near the pylon) on the front of airplane wings (full sized and model) to induce controlled turbulence which when done just right reduces drag and increases lift. Computer models are still not up to this, it is done by trial and error even on brand new designs.
You often induce turbulence to improve cooling effects. For example, in injection molding you make sure the cooling water is turbulent within the mold cooling passages.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
Where is there an air bearing in a CNC mill? One example please.
There aren't any on ether of the ones I use regularly.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
First off, it's not true that the boundary layer is immovable. The molecules within it are moving at hundreds of miles an hour. They aren't sticking to the metal and preventing heat flow. They're hitting the metal, picking up momentum from the atoms in the metal, and rebounding at higher speed. I.e., taking heat away from it. (Look up "kinetic theory of gases" in any elementary-school physics text.) If you blow on it, you will move those molecules out of the way, and replace them with cooler ones, allowing heat to flow from the metal faster. (ibid.)
Second, making the heat-sink move is no different from blowing air at it. Because that's all it's doing. It's just doing it the hard way. Like driving to work by moving the road under your car instead of your car over the road*.
Third, there's no way that you're going to get as good a conduction of heat from the substrate to the heat sink if the heat sink has to be on a moving bearing. The bearing surface will be smaller than you could get from a static surface, and friction in the bearing, which can't be eliminated, will actually add heat, which you will slow transfer from the substrate.
Fourth, it's not true that you can't make heat sinks "immune to dust". You just have to design them not to have eddies when the fan is on.
This whole topic is teh bollocks.
* - my superpower is thinking up car analogies.
TFA already does that. Heat Source->Spreader->tiny air gap with good heat transfer due to being tiny and churned->spinning heatsink/propeller.
-Richard L. Owens
About the same as nitrogen, which they used in the experiment. 0.2C/W, they think they can get it to half that. 0.05C/W is within the realm of possibility. So at least 3x better than today's coolers, maybe up to 16x better than some of them, eventually. I assume there will be a startup bearing that may not be more than a teflon or HDPE slip ring. The startup is brief, infrequent and low velocity, so there would not be much wear.
"Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery?" - Patrick Henry
Heat pipes and waterblocks still need to transfer the heat to the air, so this has the potential to improve those, too.
"Is life so dear, or peace so sweet, as to be purchased at the price of chains and slavery?" - Patrick Henry
jostling of the PC case
The Bastard Operator From Hell would like a word with you.
I assume you mean in a mobile application, and I think that the physics involved would require so much force for the air cushion to be compressed that the rest of the computer might be a goner.
What I'm more concerned with is if this fan always has to be mounted horizontally, and if I'll need to lay my ATX tower flat or manually set the fan spinning to make it overcome friction.
All rites reversed 2010
What do you do when it fails? Can you replace it for less than $10?
Obviously not. The replacement cost seems be closer to the cost of the full heat sink. If prices drop to realistic rates, it will probably be similar to today's after-market heatsinks (~ $30 - $50), maybe a little more. The motor will need to be more sophisticated (high RPM), but it won't need heat pipes.
You're right that it causes an issue, but a very minor one. Most heatsinks sold today have a built-in fan which is not designed to be replaceable.
As an aside, this white paper is old. It dates to Jan 2010. have there been any recent developments?
(ps hear != here)
I won't join Slashcott. OTOH, If Beta goes live, I just won't be back until it's fixed. Sorry Dice.
In newer machines, there is sometimes the option for the spindle to be an air-bearing, so that it can hit 10,000 to 50,000 rpm without either 1) exploding or 2) melting.
Examples: (1), (2)
So, basically by keeping the air gap very thin (30 microns), and by substantially shearing/mixing this thin air disk, its thermal conductivity can be sufficient to transfer heat up into the rotating fins. Overall a rather clever design.
I'm suspicious that this air gap is what's going to get plugged up with dust. Sure, a micro-fine particle will go right through and up the 'chimney', but a little dust bunny that dislodges will probably block the intake and then accumulate more dust.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
You realize air is a fluid, right?
Yes. You realize the post I responded to specifically called out water or oil to improve efficiency, right?
Rather than spell out "oil or water" each time, I saved a few keystrokes by just typing "fluid". It's called context. Learn it. Love it. Live it.
Yeah, when they are "dusty", the heatsink is all plugged up. I'll take dusty over plugged up any day.
A successful API design takes a mixture of software design and pedagogy.
Heat pipe only does heat transport, so what you said is true about thermal resistances somewhat, but otherwise makes no sense. It's like comparing car tires to cars. You stll need to extract the heat out of the heat pipe, and for that this device would rock compared to stationary heat sinks.
A successful API design takes a mixture of software design and pedagogy.
From what I can gather, the laminar to turbulent airflow is for removal of the boundary layer on the wing. (Producing turbulent air flow over the wing instead of laminar) I can't find anything that would suggest that it would be for removing a boundary layer (if it exists) on the propeller itself, and I sure as hell wouldn't just take your word for it.
Also keep in mind that there's only so much people can spend their time on learning, and while you might think it's common knowledge, others don't. I could start other discussions and lose you completely if I started with the field I specialize in, so commenting about denseness of /. is pretty immature.