Tiny Wind Engines Make Computers Cooler

A research team at Purdue University has announced a new method for cooling microprocessors using "ionic wind engines." Coming just in time to see application in future computer designs featuring much more powerful--and energy intensive--chips, this air-cooling technique adds a tiny electric device that sits atop the chip to create a vortex of ionized air over its surface. The resulting breeze improved the heat-transfer coefficient, or cooling rate, by as much as 250 percent, according to its inventors.

"Other experimental cooling-enhancement approaches might give you a 40 percent or a 50 percent improvement," said team leader Suresh Garimella, a professor of mechanical engineering at Purdue. "A 250 percent improvement is quite unusual."

The Purdue ionic-wind approach uses the tiny engine in concert with a conventional fan to bring cool air to where microprocessors need it most, the hot upper surface of the chip. Because of an obstacle known as the no-slip effect, in which air molecules nearest a chip's surface remain undisturbed by a generated breeze, conventional air-cooling systems fail to blow the rising heat from a microprocessor as efficiently as possible, the researchers explained.

The computer engineers quantified the cooling effect with infrared imaging, which showed the technology reduced heating from about 60 degrees Celsius (or 140 degrees Fahrenheit) to about 35 degrees C (or 95 F).

"We've been trying to make this work for about a year, and now we have shown that it works quite well," Garimella added.

He noted that the next step in their research, which has been funded by Intel Corp. and the National Science Foundation, will be to reduce the size of components within the device from the scale of millimeters to microns, or millionths of a meter. Miniaturizing the technology will be critical to applying the method to computers and consumer electronics, allowing the device to operate at lower voltage and to cool small hot spots. Another challenge will be making the technology rugged enough for commercial applications.

"As things get smaller, they get more delicate, so we need to strengthen all the elements. And we believe we can achieve this goal in a year or so," Garimella said.


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