Intel Develops Micro-Refrigerator To Cool Chips

Spacedonkey writes "Researchers at Intel, RTI International of North Carolina, and Arizona State University have made ultra-thin 'micro-refrigerators' for computer chips. The device uses a thermoelectric cooler made from nanostructured thin-film superlattice that can reduce the temperature by 55C when a current passes through it. In testing, it reduced the temperature on part of a chip by 15C without impairing its performance. The researchers say the component could be particularly useful for cooling hot spots that frequently occur on multi-core chips."

Comments

Pelletier effect?

[Fastfwd]

Is this the same as a pelletier effect? I hate fans and definitely would pay a premium to get rid of them.

Re:Pelletier effect?

[PotatoFarmer]

Looks very similar. And, like Peltier devices, the same fundamental problem remains - you've moved the heat from one spot to another, but it doesn't just disappear. You're still going to have to get it out of the general vicinity of other temperature-sensitive components, and that probably means fans.

Re:Pelletier effect?

[goombah99]

The thing I don't full understand here is how a cooling device that is the same area as the chip itself accomplishes much. It moves the heat.

It seems to me that to be more than traniently effective you still need tansfer the heat to something with greater surface area. And if the attached heatsink fins have the same surface area as before, what has been accomplished?

Arguably, if you can make the fins hotter they will radiate faster, so that could be one strategy. Or one way to gain is if you could extract work (current) from the heat. then it really would give a net cool. Usually however peltier devices actually add their own heat loads in addition to the heat transfer. Don't know about these, but the second law puts a limit on how much heat you can convert to work.

So where is the gain coming from? moving more heat with less added heat? that won't bode well for future improvements. Is it hotter heat sinks. or is it somehow managing to increase the sufface area?

Re:Pelletier effect?

[Rakh]

It might be that the cooling element can withstand much higher temperatures than the chip itself can. Thus there is a benefit to decrease the temperature inside the chip, even if it that does make the other side of the cooling device much hotter, since the heat will not be doing any damage on that side.

Re:Pelletier effect?

[AKAImBatman]

It seems to me that to be more than traniently effective you still need tansfer the heat to something with greater surface area. And if the attached heatsink fins have the same surface area as before, what has been accomplished?

Usually when a chip is running, only certain parts receive heavy use. These parts of the chip are going to be dumping more heat than the parts of the chip that are lying idle. In result, the chips has a few hotspots that are cooking your most important circuitry.

These mini-refrigerators will remove these hot spots by dispersing heat to areas that are currently underutilized. This should give the chip a more even operating temp and thus provide a greater surface area with which to disperse heat in general. The end result is that chips become more reliable and can be run at higher wattages without melting a hole through your chip. Higher wattages means that they can be clocked higher without error and thus get more work done in less time.

Re:Pelletier effect?

[blueg3]

The purpose is to move the heat within the chip. You're thinking of thermal transfer from the surface of the chip to the environment. What Intel is concerned about is thermal transfer from the component inside the chip that is generating heat to the outside surface.

Currently, chips are limited (in part) by heat production within the chip -- the heat gets to the chip surface by simple conduction. It's the components inside, generating the heat, that are going to fail at high temperatures, though.

Fortunately removal of heat at the chip's surface is not a big issue. As you note, a thermoelectric cooler could push the heat to a set of hot fins and a fan. Water coolers have plenty of capacity as well.

Re:Pelletier effect?

[DarthVain]

Yeah I was about to say: Gee congratulations, you just invented a Pelletier, oh wait that already exists.

I guess the story here is miniaturization by making it really really thin? (I didn't rtfa of course)

You are exactly right also, you are not getting rid of heat only moving it from one side of the waifer to another. Something else has to take it from there. Fans are defiantly one way, heatsinks and heatpipes are another.

The other drawback is that they use electricity to function. In relative terms, a LOT of electricity. So put that on top of a top of the line processor which already gobbles up tons of juice and you are starting to suck down an awful lot of wattage. Which of course requires a bigger PSU. Not to mention not being green and all that. Anyway devils in the details... and while I didn't rtfa, these sort of articles are usually light on that sort of thing.

Re:Pelletier effect?

[jhfry]

Imagine this...

circuit operates at 3GHz at 20C or at 4GHz at 10C. So you say, lets cool it then!

Well if you couple chip to copper heatsink and fan, you can't possibly drop temps to sub-ambient temps.

However, with a cooler, you can... so long as you can dump the extra heat fast enough.

The biggest reason peltier coolers are rarely used is that they tend to cause condensation, and they acutally generate additional heat, requiring even more cooling.

However, if you could create a small one, that was within the housing, cooled only the necessary areas, and didn't need to be sealed from the humidity... it would be this.

Re:Pelletier effect?

[goombah99]

It might be that the cooling element can withstand much higher temperatures than the chip itself can. Thus there is a benefit to decrease the temperature inside the chip, even if it that does make the other side of the cooling device much hotter, since the heat will not be doing any damage on that side.

Yes, absolutely, but that's why I said "to be more than transiently" effctive. You can only do that for so long before you are first limited by heat capacity, then conduction, and finally convection. Then you can't sustain the differential any longer. If we assume the heat capacity of the far side is roughly (in terms of being accessibly within a diffusion length) of the chip itself then the time it takes to heat it to saturation will be at most a handful of times longer than it took to heat the original chip. You can substitute what you like for "handful", say 2x or 10x, but since the original chip heats in seconds, where not talking much of anything except for transient imporvement.

at somepoint it has to expand the surface area or rate of convection.

Re:Pelletier effect?

[ByOhTek]

Consider the interface between the CPU and the heatsink - when it's been running a while, both will have the same temp...

[30C] Heatsink [40C] [40C] CPU [50C]

The heatsink is pulling heat away at the temperature of the CPU, and the air is pulling heat away at the temperature of the heat sink.

Now, heat transfer works best/faster when there is a large differential, what this will do is increase the heat being applied to the HS while drawing it away from the CPU (say, at equilibrium, the CPU will be 20C colder than the heatsink). You might end up with something closer to this:
[35C] Heatsink [50C] [30C] CPU [45C]

Re:Pelletier effect?

[CaptainPatent]

It's not so much about dealing with the heat overall, it's dealing with the heat in the hottest places. The more heat bottlenecks you get rid of, the hotter you can run the chip stably.

Don't get me wrong, the implementation doesn't come without drawbacks. There's the higher expense for the extra circuitry, and the higher electrical requirements to run the coolers. It looks like the only need for this is on high-end chips and even there it's only absolute bleeding edge that'll need anything like this, however for the enthusiast, the CAD designer, the video editor or the programmer, this may just be a breath of fresh air.

Re:Pelletier effect?

[Anonymous Coward]

Ionized particles (or whatever its called) can move air without moving parts, not sure how much more power that would consume though than using a fan, or if it would be as efficient at moving air.

Re:Pelletier effect?

[Bearhouse]

Yes

http://en.wikipedia.org/wiki/Thermoelectric_cooling

Re:Pelletier effect?

[gtbritishskull]

The rate of convection depends on the temperature difference. Heat is being diffused, constantly, so more heat can be diffused per unit time if the temperature differenctial is higher.

Re:Pelletier effect?

[hierophanta]

but would you mind condensation in your box? i'll take the fans

Re:Pelletier effect?

[Lotharjade]

Looks very similar. And, like Peltier devices, the same fundamental problem remains - you've moved the heat from one spot to another, but it doesn't just disappear. You're still going to have to get it out of the general vicinity of other temperature-sensitive components, and that probably means fans.

fans... OR Dolphins!

Re:Pelletier effect?

[camperslo]

The thing I don't full understand here is how a cooling device that is the same area as the chip itself accomplishes much. It moves the heat.

Think of heat flow as depending on two things; the temperature difference between source and destination, and the total thermal resistance in-between. The thermal resistance is usually expressed as the temperature rise in degrees C per Watt. A small amount of thermal compound filling in tiny voids reduces the resistance between the chip and the heatsink (a layer that's too thick actually adds resistance in-between). As far as the chip is concerned, a peltier device is like inserting a negative thermal resistance in series, bring down the total and increasing the heat flow. The heatsink will get hotter causing it to radiate/conduct more heat. Some of that heat is additional heat that came from the CPU, some is the heat from the power consumption of the peltier device.

End-users tend to look at just the thermal resistances from the I.C. package to ambient air, but that isn't the whole story. Are two chips with 65 Watts to dissipate equal? They might look the same to us, but a 45 nm chip being smaller than a 65 nm chip would have less surface area to transfer heat to the I.C. package. It is very likely that achieving a given chip-to-case thermal resistance is increasingly difficult as chips get smaller. With that in mind, it makes sense to be looking at new designs to improve heat flow from the hottest parts of the chip. The hottest parts matter the most since it is generally exceeding a certain temperature that causes damage or malfunction.

Some of the thermal and small-size considerations in chip design today resemble some that have been with us for a long time. Radio-frequency power transistors have had to use smaller chips than conventional power transistors for the sake of speed. Even 30 years ago, designers had to worry about metal-migration from the high current density (per unit area). Variations in temperature across a chip would lead to the hotter areas doing a thermal-runaway type thing (the properties would shift in such a way that the hotter area would take an increasing share of the current, getting even hotter...). Designers of what looked like one transistor sometimes had to break the Emitter into a number of sites run in parallel, each with an small on-chip current equalizing series resistor, just to make the heat generation across the chip more uniform.

I think some art museums really ought to have a corner for chip designs.
Many skilled artists have worked hard to make chips what they are.

Re:Pelletier effect?

[bluefoxlucid]

Shut the fuck up, that has nothing to do with anything anyone said. I read your whole post to the end, wtf are you babbling about that's anywhere near relevant?

Re:Pelletier effect?

[Anonymous Coward]

Jeeze, what are they teaching you kids in school these days?

Conduction, convection and radiation heat transfer all increase with temperature.
Heat conducted through a rectangle of area A, length L:
                    H = kA (T2 - T1)/L
                                (joules/second)

Energy radiated per second:
              H = esAT4

Convection is more complicated since it depends on the airflow.

Re:Pelletier effect?

[wastedlife]

He's just an asshole troll posting links to zoy.org along with somewhat relevant BS. Seriously, don't click the link unless you want to be flooded with gay porn popups.

Re:Pelletier effect?

[Anonymous Coward]

this may just be a breath of fresh air.

Fresh air? Wouldn't that be... ... ...wait for it... ... ...a fan?

Re:Pelletier effect?

[phulegart]

Imagine a counter top device that can keep a gallon of milk refrigerated to below 40 degrees F, and is only slightly larger than the gallon of milk... wouldn't that be excellent? OOPS already exists... uses Peltier tech to work. Oh. You can also buy a small cooler/refrigerator that runs off your car cigarette lighter... also uses Peltier.

Yes, there is a lot of talk about how much heat this thing moves. But, to be plain... if you put electricity through a Peltier, the Hot side gets hot, and the cold side... gets COLD! Yes, this means that you are not only just moving the heat from the processor to the heatsink (this goes between them), but you are actually applying a cold surface to the top of the processor. But, if that isn't clear... a regular heat sink and fan doesn't get cold (drop in temperature) on the processor side. This thing does. Ultra made a cooler that used a Peltier. http://www.xoxide.com/ultra-chilltech-cpu-cooler.html

So it isn't just about moving heat. That is part of how it works. But the right (or wrong) peltier in position on a processor can actually cause condensation to form around it. It is about adding cooling.

Re:Pelletier effect?

[dindi]

I saw a toasted motherboard in the Peltier cooler times.

It worked fine, however it worked too fine, so the little thing started condensing water .... more and more, until the machine screeched to a halt.

At which point we opened the case and the motherboard and the processor was gently cooking there in liquid .......

Not sure if that was an isolated case or not, but when you extreme cool one side, extreme heat the other you can expect some condensing happening somewhere on the cold side...

also +1 on the great cooling, but extra heat too comments

Current drain?

[Anonymous Coward]

Any word on how much current this takes? The last Peltier devices I played with took several amps; I hope they've got that reduced substantially by now.

Peltier Effect

[Lookin4Trouble]

So this is a miniaturization of the peltier effect, with the upside of supercooling one side of the film, but how do you extract the heat from the opposite side of the film? Without a large surface area and volume, liquid-cooling the opposite side may not suffice for thermal transfer...

Re:Peltier Effect

[Hrungnir]

They are putting this between hot spots of the chip and the heat spreader that normally covers the chip and gives a surface for heatsinks to sit on. So the heat is still being extracted by the heat sink, this thing just helps keep the hottest spots cooler

Re:Peltier Effect

[yttrstein]

You do it with one of these:

http://www.instructables.com/id/SH8YISTFPPG0L4D/

The heat sink for a piezoelectric spot cooler. So really no, there's not a huge amount of point until someone figures out how to do heat exchange with something other than heat conductive metals who's efficiency depends directly on surface area.

Re:Peltier Effect

[CyprusBlue113]

The idea isn't to remove the heat from the chip, the idea is to remove the heat from this ONE SPOT on the chip.
Basically they are trying to keep the core cooler, and dump heat to the transfer plate more effectively.

Re:Peltier Effect

[jhfry]

Don't think of it as a peltier cooler... think of it as a way of instantly transporting the heat away from a particular portion of an IC. It is integrated into the IC itself, so it's not a cooler, but a heat transmitter.

So, for example, if I want to "over clock" a portion of my IC, but it keeps running to hot, I could use this to extract heat from the area and distribute it where it doesn't matter so much.

Essentially... the Watts of heat you pull from your CPU, aren't generated across the entire chip, but are commonly more localized. For example, cache doesn't generate much heat. If I can take heat from the FPU and move it to the cache area, I can clock the FPU higher, and have fewer heat-related failures.

So in summery... it's not a cooler!

Re:Peltier Effect

[jhfry]

I retract my previous statement... I thought this was a different tech I read about somewhere.

This is a cooler, it's a thin cooler they are placing between the chip and it's housing.

So it's a peltier cooler after all.

Re:Peltier Effect

[blueg3]

In accordance with thermodynamics, there is no such thing as a cooler -- there are only heat transmitters. Any refrigerating device is a fancy way of moving heat from one place to another, generating a little extra heat in the process.

Re:Peltier Effect

[jhfry]

Yeah, though I doubt any scientist would dispute that a thermoelectric device that uses the peltier effect is commonly called a Pletier cooler... even if the name makes little sense in conversations between physicists.

There are many scientific products who's common name makes little sense in the context of those concerned with the theory of the device.

For example, if your an American I would bet that you incorrectly call a voltaic cell a battery. That's the common name even if it's dead wrong in a technical sense. When electronic engineers talk, they discuss a 1.5V AA size cell; while my wife would ask for a AA battery.

Re:Peltier Effect

[Anonymous Coward]

In accordance with thermodynamics, there is no such thing as a cooler -- there are only heat transmitters. Any refrigerating device is a fancy way of moving heat from one place to another, generating a little extra heat in the process.

There is nothing in the laws of thermodynamics that would imply there's no such thing as a cooler. You either badly misunderstand the laws of thermodynamics, or you badly misunderstand what the word "cooler" means. I'm guessing the latter. A cooler is something that cools something else down. There's nothing in the definition of "cooler" that dictates how it does this, so heating something else up in the process is perfectly allowed, and does not violate either the laws of thermodynamics or the definition of "cooler".

Re:Peltier Effect

[Red Flayer]

while my wife would ask for a AA battery

Your wife, sir, is she a go-er? Wink, wink, nudge, nudge, know-what-I-mean, say-no-more?

Just wondering what she might need AA batteries for, you see, and I'm afraid my imagination got the best of me. Sorry.

Re:Peltier Effect

[Antony T Curtis]

I must admit that it sometimes annoys my wife when I ask for a "Double-A Cell" for a clock but at the store, I would ask, do we need "batteries".

The enlightenment is simple... "Behold, one 'AA' Cell" .... then grab a handful and say "Behold, a battery of 'AA' Cells"

It is usually at that point when she whacks me over the head with whatever she has immediately hand for being pompous.

Re:Peltier Effect

[karnal]

From what I've seen, they're usually C sized, not AA. Only thing I've really seen use C size batteries recently.

Work seems to keep a stockpile for some reason......

Re:Peltier Effect

[Anonymous Coward]

informative? almost stupid, given the context him itself his quoting. oh, never mind. this is slashdot, this is the wisdom of the crowd.

Intel is also planning...

[Anonymous Coward]

...micro-keggers for tiny little beers and a nano-couch backplane.

Finally an architecture without that lamo fsb that Intel can be proud of.

Re:Intel is also planning...

[jep77]

I'm all for the micro-kegger but I want to keep my chips warm. When's the last time you went to a Mexican restaurant and were happy the chips were cool to the touch when they arrived.
Keep the refrigerated technology for the beer... I like my chips warm!

Re:Intel is also planning...

[Kingrames]

But the flying spaghetti bus is the most important part of the computer.

Competition

[phorm]

While many have already mentioned the obvious drawbacks (heat may drop on the most-effected areas, but it still needs to get the heat *out* of the case), if this is still an effective and innovative method for cooling then I wonder how Intel would go about licensing it. Holding onto tech that would allow for a 15c drop in core temperature would probably give them quite a strong advantage over competitors such as AMD, etc, which might be worth more than the advantage of licensing it out...

Re:Slashdot issues?

[Anonymous Coward]

im havin the same problem, whats the deal?

Imagine the Phenom II overclocks...

[elodoth]

...that you could get with this fancy TEC cooler.

Yes but ....

[Archangel Michael]

Does it reach -232 degrees Celsius?????

Re:Yes but ....

[Anonymous Coward]

In Soviet Russia, you cool chips!

Re:Yes but ....

[shootlessjoe]

Ya, I was going to say that. :D

Re:Yes but ....

[pleappleappleap]

Epic joke-creation fail.

nanostructured thin-film superlattice

[detox.method()]

It's a bird! It's a plane! It's a bunch of big words!

Re:nanostructured thin-film superlattice

[Tubal-Cain]

Let me translate:

nanostructured

It's small.

thin-film

It is a sheet, not a glob.

superlattice

I looks like chicken wire.

Re:nanostructured thin-film superlattice

[Tubal-Cain]

I looks like chicken wire.

Oops, no. It looks like a PB&J sandwich with lots of layers.

Re:nanostructured thin-film superlattice

[cparker15]

with lots of layers

So it's like ogres?

Beer?

[WillKemp]

Will it keep your beer cool while you're online?

Re:Beer?

[quickOnTheUptake]

yeah, screw putting it on the processor, just embed it in a coaster.

Re:Beer?

[WillKemp]

They could replace the coffee cup holder with a retractable beer chiller shelf.

Re:Beer?

[blankaBrew]

Although you're being funny, morebeer.com does sell conical fermenters for fermenting beer that are temperature controlled using peltiers. They are capable of getting the beer 30-40 degrees below ambient. So, I guess the answer to your question is kinda "yes".

Don't throw away your Arctic Silver yet.

[Bearhouse]

The planned cooling device(s) do not cover the entire area of the chip - they are to deal with local 'hot spots', (a temp reduction of 15ÂC is claimed - quite a big deal).

As they sit between the chip and its (unchanged aluminium, copper, whatever) packaging, the main job of conducting heat away from the chip will still be done by the heatsink & air or water cooling...

So, a cool [sic] new way to make modern hi-perf chips either faster and/or more reliable, but not a revolution.

Re:Don't throw away your Arctic Silver yet.

[DrSkwid]

Your use of [sic] is erroneous. Its purpose is to show you are copying spelling & grammar errors verbatim froma third party and you know that there is an error but chose to preserve it.

It does not just move the heat

[EmbeddedJanitor]

When you move heat, you're concentrating the heat and making the hot side hotter. Heat sinks are rated in Watts/degree so a heat sink that is 10 degrees above ambient will dump heat 5 times as fast as a heat sink at 2 degrees above ambient. Thus, a Peltier device pumping heat into a heatsink will cause the heatsink to run hotter and work more effectively.

Re:It does not just move the heat

[goombah99]

Right, but then there's nothing new here either since using peltiers to make the fins hotter is nothing new.

Re:It does not just move the heat

[Anonymous Coward]

The new thing is the miniaturization, to the point where they can target specific regions of the chip to be cooled.

Re:It does not just move the heat

[Anonymous Coward]

Also hand since Peltier devices have a have a low efficiency. 30-50% so for each watt you move you need to remove 2 watts.

Re:It does not just move the heat

[Ancient_Hacker]

That's like cutting off your nose to spite your face. Nobody cares that a heatsink is running "more effectively" the hotter it gets. That's like saying don't take aspirin cause your red glow looks so nice.

Peltier devices dissipate about 5 watts for every watt they move. And they have a limited deltac across their sides, so it's really easy to end up worse off temperature wise if the extra 5 watts heats up the heatsink more than the peltier device cools the other side.

Re:It does not just move the heat

[The End Of Days]

Too bad Intel didn't hire smart old you to tell them that before they wasted their time and money developing this. You'd think they'd know enough to run new ideas by the Slashdot panel of experts to see what the derision index from the peanut gallery is first.

Peltier's add heat, complexity, and problems.

[Zoson]

The writer neglects to mention that peltiers add their own heat load GREATER than their energy consumption, and that means you need additional cooling. Even if the devices themselves ran cooler, you would need a significantly larger dissipation device to handle the load which is now CPU + Peltiers, instead of just CPU.

Overclockers have been using peltiers bigger than the entire cores of CPU's to create a temperature delta below ambient for years. This is nothing new, just someone attempting to capitalize on a known effect.

To run a peltier you generally have to do the following:
1. Insulate your motherboard and CPU against condensation because peltiers typically drop your core temperature below ambient.
2. Provide a separate power supply JUST to power the peltier, because they typically need in excess of 200W to reliably cool a modern cpu
3. Add surface area to the final cooling point(radiators or heatsinks) to handle the added load of 200W+ to the cooling loop introduced by the peltier itself. This usually results in requiring a method of transport for the heat because no element that sits directly on top of a CPU could get big enough(you'd exceed the weight tolerances of the PCB materials).
4. Add significant temperature monitoring because when a peltier fails, or becomes overrun by heat, they become reverse pumps and will fry your processors faster than you can pull the plug from your PC to save it.

Oh, FFS

[R2.0]

It's NOT a refrigerator. Refrigerators use the refrigeration cycle to move hat from one place to another. This is basically a Peltier. That doesn't make it any less valuable for it's purpose, but why didn't they just call it a "cooler"? I mean, it's not like the audience for these types of announcements is tech-illiterate.

Re:Oh, FFS

[The Grim Reefer2]

Refrigerators use the refrigeration cycle to move hat from one place to another.

So that's where the term "Hat Trick" comes from. I've always wondered about that.

What's the carnot efficiency? acoustic cooling.

[John Sokol]

Sorry I couldn't fit what I want into the title.

Carnot efficiency is very important.

Peltier/Seebeck and Thomson effects are only 5% where compressor based systems are more like 50%

So Peltier thermoelectric coolers actually create almost as much heat as they remove. You also end up with condensation problems when the chip drops below room temperature.

We were able to reach -90C with a stack of Peltier cooler, but it was terrible efficiency.
Didn't really matter for overclocking anyhow.
But we had to hermetically sealed the computer and fill it with Dry gas and desiccant to prevent icing and condensation. We lost a few motherboards before we went to that level.

There is also Thermionic cooling, that promises to be much more efficient.

With my old company we experimented with many forms of cooling some passive (high thermal conductivity) and some active.

One of the ones I liked best was a Micro Acoustic Cooler we made. Never did get to do enough testing, but it also looked very promising, using
a gas in a very small tube that was hit with high powered ultrasonic sound waves. It was amazing to see it work.

Magnetic cooling was also interesting.

One very effective solution was a (active phase change) micro compressor based system that was equivalent to a continuously hitting the CPU with freeze spray.

Which idiot cools chips, instead of cooling beer?

[140Mandak262Jamuna]

That is all I ask. It is kind of dumb cooling the chips, I like 'em toasty. Told missus to keep the chips toasty for the Superbowl Sunday. And the beer cold. Don't get it mixed up, I told missus clean and straight so she wont get mixed. Chips toasty and beer cold.

Can this be used to cool MicroBrews?

[PDX]

Like revenge, they are best served cold. I'd like to chill a drink with a USB port connection with one of these.

Re:What's the carnot efficiency? acoustic cooling.

[zippthorne]

For refrigeration, you'd be concerned with coefficient of performance (COP), rather than efficiency. It's a related term, basically the inverse of efficiency, but it refers to how much energy you need to use to move a given amount of energy between two temperatures.

But your numbers are weird. A refrigerator at 50% (COP of 2) sounds reasonable for a small device or large temperature difference, but COP of 20 is really good.

A COP of 5 percent would be horrific. 20W required to move 1W, a modern processor would require more electricity than a two-burner electric range at full power... I'd only put up with that kind of number for very specific applications. (like, if I needed to recycle a small amount liquid nitrogen in a sealed, difficult to access device or something)

By the way, why didn't you just slather a layer of nonconductive lacquer over the motherboard? Surely that would've been cheaper than a complicated heat exchanger, desiccant and sealed box trick.

The declining technical abilities of /. editors

[Anonymous Coward]

Where's the degrees sign Â? C by itself is a coulomb!

Re:The declining technical abilities of /. editors

[Anonymous Coward]

Oh fuck, why doesn't Slashdot support fucking Unicode????????????????

Re:What's the carnot efficiency? acoustic cooling.

[blueg3]

Yes, but they're not interested in particularly low temperatures, nor are they interested in the problem of transmitting heat away from the chip's surface, but rather transmitting heat within the chip itself (or to the surface). You can't really do that with most other refrigeration systems, as they cannot be put inside the chip.

How about reusing that heat?

[blankaBrew]

This might be useful for concentrating the heat in one place. However, what about using that heat by attaching micro-sized stirling engines to generate electricity which could recharge the batteries of a laptop? That would be kinda like a hybrid laptop: recapturing the wasted energy from the inefficiencies of the processor. That's something I'd like to see.

Re:What's the carnot efficiency? acoustic cooling.

[Tenebrousedge]

The best idea I've heard for using Peltiers is in combination with mineral oil submersion, which handily takes care of both heat transfer and condensation. Power and efficiency issues remain.

Pelletier effect?

[kestasjk]

Isn't this just like the Pelletier effect? If it is cooling the chip down where is the heat being transferred to?

I'm pretty sure no-one else has brought up the Pelletier effect comparison..

Am I the only one...

[SupremoMan]

That thought about the other kind of chips? Here I was thinking "Yeah that's great, but when was the last time I wanted to eat cold chips?"

Re:What's the carnot efficiency? acoustic cooling.

[John Sokol]

why didn't you just slather a layer of nonconductive lacquer over the motherboard?

Because that would cause other components to overheat like the North Bridge and CPU power regulator on the MB.
It's also just wet and ugly and makes it hard to maintain, not something we could put into a commercial product. Also you really need to make sure water doesn't get under the CPU. So you'd have to permanently glue the CPU to the MB with varnish to do what your suggesting.

Carnot efficiency:
        E = 1 - Tl/Th

coefficient of performance:
        COP = 1/(Th/Tl -1) in one book
        COP = Tl / (Th - Tl) in another
and COP = Th / (Th - Tl) in yet another.

I can't get any clear definition of COP!
So I choose not to use it until I can find someone who can give me a clear definition.

I can't find my references on efficiency of different cooling now.
But I know freon systems were 25 to 50% efficient and Thermoelectric was like 5%
It's been 6 years since I dove into this.

But Know we had to dump something like 200 Watts to remove 100 with Thermoelectric. So our heat sink had to cope with 300W and not just the 100 from the CPU.

Other references.
http://www.coolchips.com/technology/ccalc.shtml
http://en.wikipedia.org/wiki/Thermal_efficiency

Re:What's the carnot efficiency? acoustic cooling.

[John Sokol]

I think that is not a correct assumption.
The freeze spray will could go directly onto the silicon, like in the AMD processors.

But cooling the surface of the heat spreader just a little further will be almost the same effect, unless the power densities get crazy.

But I have found even a passive phase change directly on a chip surface is plenty efficient for limiting chip temperatures. Problem is making good seals then.

Even passive thermal conductors we found that we could pull 400+ watts from a CPU chip and keep it under 70C in a room that was 35C!

Re:What's the carnot efficiency? acoustic cooling.

[John Sokol]

http://www.silentcomputing.com/i.html

Is this cleaner then mineral oil submersion?

Mineral oil is a complete mess. A friend of mine wanted to do it and that's how I got into coming up with alternatives.

With mineral oil it's a disaster waiting to happen. Imagine a gallon of that on your carpet?
What about fires? Yes a few gallons of flammable oil in your bedroom is just genius. Then run electricity through it.
  Why don't you just keep a full gas can under your bed while your at it.

Mineral oil also tends to wick up the cables and dissolve some plastics.

What if you want to work on your PC?

Oil is just not professional.

Condensation is not an issue with this design

[QuestionsNotAnswers]

They are only drawing heat away from the *hottest* small areas (not cooling the whole chip) - the spot temperatures can still be well above room temp.

Also it seems obvious (for power efficiency reasons under low loads) they would integrate temperature sensing with each cooling element so that the cooling is only activated when that particular part of the chip is generating heat i.e. not cool anything below the dew point.

Micro fridge

[emandres]

Micro fridge, eh? Well now I just need to get some micro brew and we'll have a micro-rave.

Re:What's the carnot efficiency? acoustic cooling.

[Anonymous Coward]

That might be cleaner, but I'm sure it's much more expensive. Mineral oil is not particularly flammable, having a high flash point and autoignition temperature. One would likely be able to extinguish small flames by immersing them in mineral oil.

Gasoline, on the other hand, has a flash point of about -40 degrees. Additionally, it is highly volatile. Your comparison regarding beds lacks merit.

The wicking is fixable, as detailed in the link I provided. Also, running electricity through it is not a problem, because it is not conductive.

Mineral oil does have the potential to erode some plastics, however, the Puget Systems people ran their system for over a year without any mishaps. The obvious conclusion would be that the mineral oil did not degrade any of the plastics contained within their rig.

"What if you wanted to work on your computer?" I'd recommend removing the parts from the mineral oil first, although I suppose it wouldn't be strictly necessary.

Your ignorance leaves little room for condescension, it would seem. Perhaps we should therefore not rely on your judgment as to what is professional.

With all due respect,
-Tene

Re:What's the carnot efficiency? acoustic cooling.

[Tenebrousedge]

I can't imagine how that was posted anonymously. Ah well. My mistake, I'm sure.

I *WILL* make noise

[DrSkwid]

> Fans are defiantly one way

curse of the spell check :>

Re:I *WILL* make noise

[DarthVain]

Technically STILL correct. :)

I don't know of any two way fans. Would be somewhat counterproductive don't you think!

Thermoelectric devices

[fixmedaily]

Thermoelectric "Pelletier" devices have been around for decades. The problem is for one side to cool the other side gets hot. You have to build a inverse pyramid with them to get rid of the heat. They fail often and go into thermal runaway. Just like Intel to re-spin what has already been tried. Try thinking for yourselves! The amount of current the devices take to cool is also prohibitive.

They should enter

[ctrl-alt-canc]

into the micro-brewery business http://en.wikipedia.org/wiki/Microbrewery