Tiny Bubbles Key to Cooling Crazy Hot CPUs

Smaz writes "With future CPUs expected to generate as much as four times the heat of today's processors, wicking away that heat remains one of the biggest engineering hurdles in the biz. Researchers at Purdue have developed a pumpless liquid-cooling system that removes nearly six times more heat than existing systems. The trick, it seems, is in the tiny bubbles. From the Science Blog."

Comments

Pumpless circulation

[stanmann]

I thought that with a properly pressurized closed system that convection and boiling would keep things cool enough. I know this isn't the first silent system, I'm just curious what special benefit the "tiny bubbles" and microchannels provide... unless we are going to another proprietary IBM standard bus.

Cavitation?

[Ungrounded Lightning]

It will be interesting to see if the shock waves from the cavitation (the sudden formation of the tiny bubbles) affects the operation of the chip or erodes the surface, limiting the life.

Re:Cavitation?

[iggymanz]

The sound waves from hard disks and power supply fans surely already make more vibration on the CPU than this would

Re:Cavitation?

[Guignol]

What your parent talks about is cavitation, the vibration you talk about is also a problem, but it has nothing to do with cavitation.
What your parent reffered to was the formation of very tiny bubbles that quickly collapse and release microjets which are very damaging to surrounding surfaces.
Those tiny bubles also have the (generaly) unwanted property of always orienting themselves so as to send the microjet against the surface of contact, thus making the problem more severe and less unlikely to happen that it might sound in a first thought.
Those nasty microjets can do a lot of damage and are the reason why stainless steel helices of boats still get corroded.
In the case of the proposed cooling system, the surface of the channels might be attacked by the released microjets until perforation, since it is so thin.

This brings me to my favorite rant...

[mykepredko]

Where does the heat go?

This seems like a nice technology to remove the heat from the CPU, but what I'm always wondering about is, where will the heat actually be dissipated into the environment? At some point, there has to be a heat exchanger where all this heat collected in the tiny bubbles is passed outside the unit. This is going to take a fair amount of space - one of these days we're going to see ads for heat exchangers that take up less space than the "standard" box available from Intel.

I'm looking forward to a Beowolf cluster not only performing amazing calculations but also heating the building it's in.

myke

something wrong

[kEnder242]

As liquid flows through the channels, it is heated by the chip and begins to boil, producing bubbles of vapor. Because the buoyant vapor bubbles are lighter than the liquid, they rise to the top of the tube, where they are cooled by a fan and condensed back into a liquid.

I see two things that might be a problem

-The chip needs to be at the boiling point of the liquid, maybe not a problem (freon anyone?).
-What happens when the CPU isn't pointing up? (e.g. on a motherboard in a standard case) Will it overheat because the bubbles don't "rise"?

Re:yeah

[glesga_kiss]

Bong makers are aware of this fact as well. Putting a bit of cloth/gause over the pipe at the bottom will make the air flow into lots of smaller bubbles, rather than a few large ones. Most surface area, more cooling.

I'd love to submit an "Ask Slashdot" article on the making of bongs. I'm sure we'd see quite a few novel ideas from the MacGyver Smokers out there...

Solid conductors

[evilviper]

I don't see why there is so much effort on dispersing heat... It seems that the only reason systems have a fan is that it's the cheapest cooling method.

Want silent cooling??? Design a case where the healt-sink goes from the processor, to the outer-shell of the case... Presto, no more restricted airflow, and no fans at all.

Convection works well when there is a large surface area (unlike current CPU heatsinks), and there is little impediment to airflow (unlike current systems).

In fact, you could have some incredibly hot systems if you designed a case with a large, EXTERNAL, healtsink, mounted so the top is flush with the case. It could look like a grill on the top of your case instead of a flat piece of metal, but be connected to the CPU with copper/aluminum.

I've always been wondering why nobody designs computers that conduct the CPU heat outside the case. Anybody have some ideas?