Bell Labs Plants Nanograss to Cool Mobile Chips

LoadWB writes "TechWeb has an article about Bell Labs' new liquid cooling technology for mobile processors. The tech, called 'nanograss' is described as 'tiny tubes that spray liquid on chip hot spots.' The use of this cooling technology reduces the power required to actively remove heat from mobile processors. Other applications are possible, but it seems it was primarily developed for use with mobile CPUs."

Comments

Yes ...

[kimsh]

but can you smoke it?

Re:Yes ...

[Erratio]

You'd need a nanobong (or nanopipe or nanopapers, etc.) and a way to hold it. Then you'd just have to make sure you don't get pulled over by any cops with microscopes.

What's next, the nano-bong?

[Sean Clifford]

What's next, the nano-bong?

Seriously, though, the technology looks pretty cool. The article likens it to a radiator so liquid is recycled in the closed system and liquid applied to the spot that needs it most. Only the requisite amount of liquid would be pushed through the system in order to reduce energy costs of pushing the liquid. Neat stuff.

New error message....

[SmackCrackandPot]

Error 0C001A41 - Processor has run out of liquid coolant. Please refill, then reboot.

Re:New error message....

[Anonymous Coward]

Gives a new meaning to leaky apps or leaking memory.

Where does the energy go?

[Anonymous Coward]

You still have the problem of getting the energy from the cpu out of the computer, just because you move it from the chip to the liquid doesn't really help all that much in itself. You still have all the same old problems. Apparently they have managed to come up with something, but it doesn't really seem to be such a great innovation as it is being hyped up to be..

Re:Where does the energy go?

[Awptimus Prime]

but it doesn't really seem to be such a great innovation as it is being hyped up to be..

Thanks, you saved me from starting a thread on that issue. I kept thinking "well, where does all this fluid go to cool off?".. The amount of fluid and circulation will be dependant on the CPU. If it's a hot running P4 or AMD64, then the resivor needed for proper cooling will be similar to that of a normal water cooling kit. While eliminating the need for a water pump, which can be made tiny enough to be insignificant compared to whatever you have to use as a radiator to dissipate the gathered heat.

Personally, I'd trust a water cooling rig before something like this. Due to the teenie, tiny nature of the tubes, I could imagine any microscopic particles in the fluid would eventually clog it up. For instance, the chemicals released as the processor ages would be likely to collect and clog an area a few microns across, easily. Since it's a passive system, there would be no means to flush the blockage out via the pump. At least with normal liquid cooling, the user can repair problems before they cripple the system. With a solid-state solution like this, you'd be dead in the water.

Re:But doesn't that mean ...

[prat393]

No, it's collected somewhere, cooled, and reused. It's a closed system; the article compares it to a car radiator.

Nano Nano

[Anonymous Coward]

In other news, John Deere has just released the "NanoMower".

The NanoHippy add-on (for nanograss collection) is TBA. NanoNarc soon to follow. No word as to the cooling effects of either.

Hmm. . . .

[ookabooka]

Brings a whole new meaning to watering the grass. . .
Seriously though, its nice to see some new heat dissipation technologies. . . but it still comes down to how much thermal energy the chip pumps out. . . this is merely equivalent to a more efficient fan/heatsink. Though it should keep the chips at a cooler temperature (compared to their standard air counterparts) your laptop is still gonna get way too hot to put on your lap.

Re:Hmm. . . .

[moreati]

If it works, it will push the envolope, improving not just total power consumption, but weight, volume & temperature also.

We already have water cooling at the macro level - a radiator + pump + heat exchanger + resevoir system will give a lower temp and less noise for the same or better heat removal capacity eg . these.

The improvement this would provide is watercooling at the micro level, just to the most critical components. The improvement in heat conductivity from the chip to the cooler should mean lower temps for the same transfer. Cooler.

The bore of the tubes implies 50 ml liquid, rather than upto 1 litre (2 pints) currently used. Lighter.

Less water for the same heat transfer means a smaller pump. Lower resistance in the chip due to lower temps would mean less power disipation. Longer running on batteries.

On the air side (dissipation from the cooler to the environment), heat exchanger tubing with ~100 micron diameter (the artivle soesn't say they've done this, but it seems a logical extension) gives enourmous surface area/unit volume, giving better dissipation for the same airflow. Quieter.

So I would surmise this is ideal for laptops, it improves all 3 of the key features - weight, longevity and actually-able-to-use-it-on-my-lapiness.

Will the pipes clog?

[Anonymous Coward]

It's cool, but it sounds awfully complex. Wouldn't small amounts of impurity gum up the works pretty quickly?

Re:Will the pipes clog?

[King_TJ]

Yes, probably so.... but since it's a *closed* system, this would presumably not ever happen unless part of a "nanotube" broke off and started floating around in the fluid, or something along those lines.

It's sort of like saying "A hard drive sounds like a cool idea. But wouldn't a small amount of dust gum it up?" Yep - but that's why they're sealed, air-tight, and initially built in clean rooms.

Wow

[Un0r1g1nal]

This looks like really good stuff, being able to localise the temperature dissipation would be handy for lots of technologies. I hope that this one gets developed fully and hits the markets soon. The better the cooling capacity the more we can clock our chips :)

As for having to refill the cooling agent periodically, I doubt that this would be a problem with mobile phones, this would be a completly self contained cooling system, much like a heatsink is today, (only a heatsink doesnt have a liquid running around the inside of it :P). The likelyhood is that by the time the liquid would need replacing - if ever, the phone would be at lesat a few years old, and so the owner would probably have it lying around in some drawer since they got their brand spanking new top of the range all singing all dancing holographic video phone...

Re:Maybe Apple can use this

[Awptimus Prime]

Ahhhh.... G5 powerbook....drooling...

That's an aweful lot of power for a one-button mouse to be in charge of!

Re:Maybe Apple can use this

[MukiMuki]

What the heck are you all happy about, they basically just invented bukkake cooling!

Cost?

[Bl33d4merican]

Sure...this is a great idea, but how much will it cost? Anybody else remember the days where a good cpu fan cost significantly more than the $20 it does today? Not to mention the cost of refilling the coolant. Yes, you will have to do that. Those of us who have a car know that the radiator fluid must be changed ...oh every five to eight years or so. Keeping in mind the a computer's life span is much shorter, but also taking into account that a computer is often left on and running for days on end, it would probably have to be replaced at least once or twice. I also doubt this is something most users could do--and even some techies might have problems. (Is the coolant toxic?) How much would it cost to have somebody 'service' your computer's cooling device? If such problems aren't answered I doubt the product will be viable in the home-use market.

usually called MEMS fluidics

[Anonymous Coward]

This was called MEMS fluidics before, and is being researched at many places for at least 2-3 years now. The term nanograss is just a buzz word to take advantage of the term "nano". If the channels are 100s of microns, how can they be "nano"? Its obviously a marketing term. Lots of research is going on in MEMS fluidics, specially for molecular biology and diagnosis. Thinsg like lab-on-a-chip, etc.

A word from technology inventor

[nanograss]

Guys, certainly a great pleasure to see so much interest in our technology.

Unfortunately, the TechWeb article is not that accurate. In particular, the statement that "nanograss" consists of tiny tubes that can spray liquid on chip hot spots is totally off mark.

What we call "nanograss" is a carpet of tiny nanocolumns (or nanoposts, but not tubes) each several hundred nanometers in diameter that cover the surface of say microchannel. The posts are treated with water repellant polymer coating and thus are not easy to wet. As the result the cooling liquid (such as water) can't penetrate inside this carpet and stays suspended on the tips of the nanoposts. Thus, flow of a liquid in a microchannel that has walls covered with the nanograss requires much less pressure head than in a regular channel. The liquid literally slides along the walls without touching them suspended by a tiny layer of air as in air hockey table.

Now, the trick is that we can intentionally design the nanograss such, that it can hold the liquid suspended on nanoposts only at the temperatures below a certain predetermined threshold. If the temperature exceeds this threshold the liquid sags through the nanograss and gets into direct contact with the wall. Needless to say that in this case thermal transfer from the wall to the liquid is greatly enhanced; the thin layer of air that isolates the wall from the cooling liquid is now gone. Thus the microchannels with the coolant that are located above the hottest areas on the chip (so-called hot spots) will have coolant penetrating through the nanograss and thus provide much better cooling exactly where the hot spots are. The system is self-adjusting and would automatically adapt to any arrangement of the hot spots. The obvious applications are in CPU and GPU cooling, as well as in telecom power electronics.

In addition to the application in cooling, there are multiple applications in other areas, ranging from electrical nano-batteries and biochem lab-on-a-chip devices to seagoing vessels. Indeed, wherever we have liquids we also have solid surfaces that contact them; thus you can think of a countless nanograss applications out there.

For those of you who are interested in further details the link to the Bell Labs press release is

http://www.newstream.com/cgi-bin/display_story.cgi ?12664

Also, the work will be published in May, 11 issue of Langmuir.

Best Regards, Tom Krupenkin

Re:A word from technology inventor

[nanograss]

There are two reasons. First of all, in order to achieve the most effective cooling at the minimal coolant flow rate what you really want is to keep the whole surface of your chip at a constant predetermined temperature (which is mostly defined by the nature of the chip and the temperature of the surrounding environment). The heat flux that you can transfer through the wall to the fluid is directly proportional to the temperature difference between the chip surface and the cooling liquid, with the coefficient of proportionality called heat transfer coefficient (this is sometimes referred as a Newton's Law of Cooling). The heat flux is distributed over the chip very unevenly, with the hot spots providing much higher flux than the rest of the chip. Thus, in order to keep the chip temperature constant over the whole area you need a way to adjust the heat transfer coefficient depending on the particular location on the chip surface. Nanograss gives you exactly this ability, as I described in my earlier message.

Secondly, nanograss provides you ability to strongly reduce the pressure drop required to push the liquid through the microchannels in your cooling system. Thus, you can use much smaller pump to push the coolant around.

In the existing systems no optimization like the one described above is attempted. As the result one ends up substantially overdesigning the cooling system in order to keep the chip (and especially the hot spots) cold enough.

Hope this helps.

Tom