New 3D CPU Water Cooling Method

captain igor writes "According to this story on Wired News, a new company launched by researchers from Stanford has come up with a way to layer a silicon network of tiny tubes on top of a microprocessor. The system then uses a solid-state motor (no moving parts!) to pipe cold water through the silicon network. According to the article, this system can handle 1000 watts (yes, a kilowatt) per square centimeter."

Comments

Oh Great....

[GeneralEmergency]

Now my PDA can wee-wee in my pocket.

Pump with no moving parts?

[Keck]

Forget about the cooling, tell me more about that pump! /me googles electrokinesis ..

apparantly it uses osmotic pressure to drive it, how cool is that?

How long...

[YuppieScum]

...before someone at IBM notices their use of 'MicroChannel'?

It's not a motor

[signe]

It's not a solid state motor. I dare say, there's no such thing. By definition, a motor turns, therefore it has moving parts. In fact, the word "motor" appears nowhere in the article, so I'm not sure where the submitter dreamt that up.

It's a solid state pump that moves an electrolyte through it using osmotic pressure.

-Todd

Re:It's not a motor

[CaseyB]

By definition, a motor turns, therefore it has moving parts.

No. A motor is by definition "one that imparts motion". This device certainly qualifies.

Re:It's not a motor

[CaseyB]

No one ever, ever refers to such a thing with no moving parts as a motor, until today Probably because such devices are rare.

but it's apparently correct because of some loose dictionary.com definiton.

No, it's correct because that's the definition of the word. Just because you've created some narrower meaning in your mind doesn't make it so. I imagine that many people considered "vehicle" to mean "something that conveys cargo on land or on water" before airplanes were invented.

If it has no rotor, I dare say it isn't a motor.

That's funny. You must be terribly confused by the way all those space vehicles get into orbit without motors!

Cool Suit

[binaryDigit]

/. is acting weird, so someone will probably have posted a similar idea, but ...

If you could figure out a way to sew this into material, then you could have some really "cool" (literally) clothing. I'm sure people like the Army would be very interested in a suit or body armour that offered effective cooling, esp in the desert where a system with a motor could be undesireable. I know it would be sweet to get a set of motorcycle leathers with something like this built in (those Texas summers get a bit toasty).

stove top boiling water experiment

[goombah99]

lets do some order of magnitude, spheical cow type estimates using simple everyday experience in the kitchen.

A typical stove top burner is order of magnitude 1000 watts spread out over around 500 sq cm: so were talking order of magnitude less than 10 watts per sq cm.

if I take a teaspoon of water an put it on a sq cm of stove top and it boils in far less than a second. really almost instantly so its probably like less than a tenth of a second.

Thus if this thing is going to not explode, the flow rate required to avoid boiling at 1000 watts /sq cm is going to be on the order of hundreds to thousands of teaspoons per second.

If I take a tiny swizzel straw and try to suck through it I cannot suck 1000 teaspoos per second. Since my ability to suck is probably within an order of magnitude of the cavitation pressure for atmospheric pressure water a pump trying to flow this stuff through an equally small crossecttion may not be able to sustain such a flow rate. And any on-chip pump is probably going to have a simmilar crossection for its fluid intake port. (off -chip is another matter)

unless this thing is actually flowing the water based on the steam pressure itself, I'm skeptical that this can meet the claimed specs.

but I assume these people aren't fools. Perhaps the science reporter slipped a few digits.

Re:stove top boiling water experiment

[Thagg]

Say water goes in at 30 degrees C and comes out at 50 degrees C. According to the spectacular Google calculator, 1000 watts is 239 calories per second, and it takes 1 calorie to increase the temperature of 1 cc of water 1 degree C, so you'd have to move 239/20 or about 11 cubic centimeters of water through the cooler every second assuming a delta-v of 20 degrees C. Doesn't sound unattainable.

thad

Re:stove top boiling water experiment

[rcw-home]

This is a lot easier if we stick to metric units.

The factor they always leave out is how much of a temperature rise one can tolerate at the heat sink. Let's assume that the incoming water will be no higher than 40C and the CPU can become no hotter than 60C - that's 20C rise.

1 kilowatt is 1000 joules per second, or 238 gram calories per second. Conveniently, a gram calorie is the energy needed to raise a gram of water one degree celcius. For water, one gram is also one milliliter. So, a single gram of water will be raised 238 degrees C in one second. We don't want it to be raised more than 20C, so we need to exchange water at a rate of 238/20 = 11.9 mL/sec.

Heat sinks aren't perfect - the outgoing water will always be colder than the CPU. Let's pretend that this sink is 50% efficient (the CPU rises to a temperature, relative to the incoming water, of twice that of the outgoing water). Ergo, we need 23.8 mL/sec.

How is this a problem?

Next step: in the processor

[hcetSJ]

I wonder how long until we have nanotubes running all through the processor. There's a professor at my school doing research on 3-D photolithography, which would allow much more complex structures to be built out of crystalline silicon. This sounds like a good application.

Re:modded offtopic

[exhilaration]

I thought the network guys had finally blocked Slashdot. It's a good thing it came back before I finished loading my gun.

I'm sure it will be sealed with non-water coolant.

[antimith]

Considering the consequences of a little algea or whatever in tubes so small, I'm sure they'll provide the coolant(likely non-water) and perhaps even an on board Closed coolant system.

Considering the size of 3rd party coolants shown on site's like Tweak3d.net I wouldn't be suprised at all if the setups didn't look like some of ThermalTakes larger models.
If most of the tubing is kept in the in-die, and the motor is solid state (not sure what size we're talking about) then I'd envision something that would leak about as mutch as an air cooled system. hehe.

Re:Power from waste heat

[Baron_Yam]

Actually, I wonder what the theoretical limit is on converting waste heat back into electricity in a laptop... would it be worth the extra weight? Even if it's NOT worth the extra weight, it might be fun to do it just because it can be done.

Off the top of my head, though, I'm not aware of any laptop-scale device for generating power from a heat source.

What if a nano-pipe bursts?

[192939495969798999]

How much force would it take to burst a pipe? I would think that would be instant death for your cpu... imagine THAT for a blue screen of death -- "Sorry, your CPU has drowned. Go buy another one!"

Re:G5 laptop now possible?

[Cecil]

No, actually, they're not because the G5 is excessively hot, nor are they for show. They are for maximizing the efficiency of the 9 (VERY low speed) fans in moving heat out of the system with minimal airflow

People assume that because the G5s have a extremely well-engineered cooling solution that the G5 is also extremely hot. It's simply not true, it's all about noise reduction.

I concur

[goombah99]

Yep you're answer is better than my initial post. I agree with your math. (4.8Joules/gm-C)

my post erred because the reason the water boils is not the heat flux but the stored heat in the stove top coil. The transient delivery of this stored heat vastly exceeds the rate of power delivered to the stove and thus the water boils fast. but this would not be sustained.

I withdraw my original answer.