Innovations: Beating the Heat

« Washington Engineer - August 2006

EE researchers use electrical charge to cool tiny microchips

: Undergraduate student intern Michael Fox (left) and UW doctoral student Nels Jewell-Larsen show off a set of newly fabricated micro cooling devices. The two are part of Alex Mamishev’s research team that has created the first working prototype of the devices, which use an electrical charge to create tiny cooling jets of air.

University of Washington researchers have succeeded in building a tiny cooling device small enough to fit on computer chip that could work reliably and efficiently with the smallest microelectronic components because it uses an electrical charge, rather than liquid or fans, to create a cooling air jet right at the surface of the chip.

It is the first time that anyone has built a working device that uses the method, according to Alexander Mamishev, associate professor of electrical engineering at the UW and principal investigator on the project.

“The idea has been around for several years,” Mamishev said. “But until now it hasn’t been physically demonstrated in terms of a working prototype.”

Mamishev and doctoral students Nels Jewell-Larsen and Chi-Peng Hsu presented a paper on the device at the AIAA/ASME Joint Thermophysics and Heat Transfer Conference last month, and are scheduled to give an additional presentation this fall. In addition, the UW researchers and collaborators with Kronos Advanced Technologies and Intel. Corp. have been awarded a $100,000 grant from the Seattle-based Washington Technology Center for the second phase of the project.

The technique, officially known as electrostatic fluid acceleration, utilizes an electrical field to accelerate air to speeds previously possible only with the use of traditional blowers. Trial runs showed that the prototype device significantly cooled an actively heated surface on just 0.6 watts of power.

The findings are significant for future computing applications, which will incorporate denser circuitry to boost computing power. More circuitry equals more heat and a greater need for innovative cooling technologies that go beyond bulky, noisy and relatively inefficient fans and blowers. Circulating liquids among the chips to draw away heat is one possibility, but computer chips and liquids don’t mix well; the cost of a cooling system breakdown could be steep.

“The beauty of this concept is that is still uses air to cool the chips,” Mamishev said. “It promises to be as efficient as using a liquid, but it’s safer and more adaptable to increasingly smaller circuitry.”