Cooling electronics in small devices such as laptop computers, PDAs and cell phones is a growing engineering concern as processors get more miniscule and more powerful. The combination of more power and less space makes it harder to dissipate heat the chips create; moving that heat has become an increasing challenge.
Now, engineers have harnessed the same physical property that drives ionizing air purifiers to create a miniaturized device that is ready for testing as a silent, ultra-thin, low-power and low-maintenance cooling system for electronic devices. Developers Dan Schlitz and Vishal Singhal of Thorrn Micro Technologies, Inc., in Marietta, Ga., say the compact, solid-state fan, known as RSD5, is the most-powerful and energy efficient fan of its size—only slightly larger than a dime. Yet it produces three times the air flow of a typical small mechanical fan.
"Some electronics tend to run hot and require cooling. Other electronics, because you can't put cooling on them, have to limit their capabilities," said Schlitz. "So this will allow designers to put higher-functioning processors in places they would not be permitted to because of cooling issues."
The RSD5 incorporates a series of live wires that lie within un-charged, contoured conducting plates. The contoured platform forms part of the heat sink, a trick that enabled Schlitz and Singhal to both eliminate some of the device's bulk and increase the effectiveness of the air flow. When the wires generate an ion-rich gas, the ions push air molecules from the wire to the plate, producing a wind.
What's more, the contour allows control of the micro-scale electrical discharge to produce maximum air flow without risk of sparks or arcing. As a result, the new device yields a breeze as swift as 2.4 meters per second compared with airflows of 0.7 to 1.7 meters per second from larger, mechanical fans.
"The RSD5 is one of the most significant advancements in electronics cooling since heat pipes. It could change the cooling paradigm for mobile electronics," said co-developer Singhal.
RSD5 also handles dust better than its predecessors do. While dust attraction is ideal for living-room-scale fans that provide both air flow and filtration, debris can be a devastating obstacle when the goal is to cool an electrical component.
The culmination of 6 years of research, the micro-fan is now nearly complete. Schlitz says the technology could be in a product by 2009 at a price comparable to conventional electronic cooling systems.
Schlitz and Singhal presented their RSD5 fan this week at the 24th Annual Semiconductor Thermal Measurement, Modeling and Management Symposium in San Jose, Calif.
This work was supported by the National Science Foundation's Small Business Innovation Research program which aims to increase the incentive and opportunity for small firms to undertake cutting-edge, high-risk, high-quality scientific, engineering, or science and engineering education research that has potential for high economic payoff.
—By Josh Chamot/NSF
This report is provided by the National Science Foundation, an independent federal agency that supports fundamental research and education across all fields of science and engineering, in partnership with U.S. News and World Report.