Researchers cool CPUs with nano-size fridges

Cramming ever more transistors into CPUs has not troubled chipmakers Intel and AMD. The problem, rather, has been how to handle the extreme heat generated by the movement of so many electrons in such a tiny space.

With heat sinks and fans not up to the task of cooling the 100 degree Celsius and greater chips, makers stopped trying to raise processor speeds several years ago and moved to building multicore CPUs instead.

[ Stay ahead of advances in hardware technology with InfoWorld's Ahead of the Curve blog and newsletter. ]

Gamers and performance fanatics responded by using water, liquid nitrogen, and other exotic liquids to cool their overclocked CPUs.

And it's not just overclockers pushing the envelope. AMD has gotten into the act, this month enabling its new Phenom II desktop processor to run at a record 6.5 GHz by cooling it with liquid nitrogen. And liquid cooling is even gaining interest from the far-more-conservative server and datacenter crowd.

However, the danger of mixing liquids with electronics remains, despite containment efforts.

Chip cooling's next generation

Now, a more elegant solution is on the horizon. Researchers at Intel, RTI International, and Arizona State University have developed a micro-refrigerator that can be easily mounted on chips to draw heat from hot spots with surgical precision.

That would allow these nanoscale (10 micron) systems to be smaller and use less electricity than conventional heat sinks, fans, or liquid setups, said Dr. Rama Venkatasubramanian, a senior researcher at RTI and a co-author of a paper published this month in the scientific journal Nature Nanotechnology.

The refrigerator in your kitchen uses a mechanical heat pump to compress and circulate a coolant liquid that absorbs heat inside the fridge and dissipates it outside.

The micro-refrigerator is quite different. It is a superthin film made from thermoelectric molecules such as Bismuth telluride and Antimony telluride.

Thermoelectric materials such as these convert heat into electricity. In other words, "you're using electrons to pump heat away," Venkatasubramanian said.