— The microchips inside future computers could be chilled by tiny "ionic wind engines" that use an electric current to generate a cooling breeze.
Researchers at Purdue University in Indiana, US, are testing the engines as a way to cool computer components more effectively. As microchips become ever more powerful, and manufacturers try to pack them closer together inside computers, it becomes increasingly difficult to cool them properly. Keeping components cool in large data centres can cost many millions of dollars each year.
Microchips are normally cooled using a heat sink, which absorbs and dissipates heat, and a small fan. Adding ionic wind engines to this set-up could dramatically improve cooling, says Suresh Garimella, who is developing them with colleagues at Purdue University.
The ionic wind engines would not do all the cooling themselves. Instead they would increase the efficiency of a conventional fan, by stirring up air molecules that would otherwise remain stationary near the target surface.
Experiments conducted by Garimella's group suggest that ionic wind engines combined with a conventional fan could increase cooling by up to 250%, although an array of wind engines would be needed to provide enough cooling for a normal processor.
The results have been accepted for publication in the Journal of Applied Physics, Garimella says.
An ionic wind engine generates wind using an electric current passing through the air between two electrodes placed close together. As electrons flow between these electrodes they collide with air molecules, creating positively charged ions that are then attracted back to the negatively charged electrode. This creates a small, concentrated breeze.
The researchers used stainless steel wires 50 micrometres in diameter as the electron emitter and a strip of copper tape about 1 millimetre wide as the electron collector. They put the collector on a heated piece of glass and suspended the emitter 3 millimetres above it. Eventually, the collector will sit on top of the microchip that needs cooling.
Nels Jewell-Larsen, who works on ionic cooling at the University of Washington, says the idea has merit.
"I think the technology is very intriguing and has a lot of interesting possibilities," he told New Scientist. "You're able to apply airflow where you need it and when you need it."
But he adds that the Purdue group must do more work before the idea can be commercialised. For one thing, the relatively high voltages currently needed to generate ionic wind - 4,575 volts - would add significantly to the cost and complexity of a computer's design.
In addition, there may be complications when ionic wind engines are packed together in large arrays.
Providing such concerns can be overcome, the Purdue researchers believe the technology could be on the market by about 2010.