Tiny Pump Cools Chips

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A different advanced method of cooling chips involves using pipes to pump liquid coolant throughout the system, similar to the way a car's engine is cooled. Apple's new Mac Pro desktop computer, for instance, uses a pump that pushes water through pipes. But these water-cooling systems are complex and expensive, Mamishev says.

The ion pump is a "potentially important enhancement," says Thomas Kenny, professor of mechanical engineering at Stanford University. But he adds that it's still unknown whether the system will face economic and technical challenges similar to those with water-cooled systems.

Mamishev's team is not alone in the use of ion pumps to cool chips. Similar technology developed at Purdue University in West Lafayette, IN, is being commercialized by a startup called Thorrn Micro Technologies. Their approach is to use metal wires instead of a silicon tip, says Suresh Garimella, professor of mechanical engineering at Purdue. Applying a strong voltage along the wire creates an electric field that ionizes air along its length, not just at the tip, he explains. The company is developing a system for cooling laptops and other portable devices.

Mamishev says there will be challenges with his group's technology as they try to integrate an ion pump into an actual product. Because of the high voltages used to generate the cooling effect, there could be an accumulation of static charge, hindering device performance, or the voltage could break down insulation in parts of the circuit. "You have to be careful," he says. Also, the group needs to do tests to determine the longevity and reliability of the ion pump.

The researchers are currently developing a prototype ion pump, which is built into a heat sink. Mamishev expects the technology to be ready for commercialization in servers, desktop computers, and laptops within two years.