Air Conditioned Computer Chips

Heat is the enemy of computer processing chips. Scientists at Purdue University are researching a new way to cool down high powered computer chips. They are taking a page out of air conditioners and applying it to super high powered chips used for aerospace and military applications. The typical household computer microprocessor rarely puts out heat in excess of 100 watts per square half inch. They typically use an air fan and a heat sink to dissipate heat The Purdue scientists are working on cooling chips that produce over 1000 watts of heat per square half inch. Issam Mudawar, a mechanical engineering professor at Purdue is leading the research along with two mechanical engineering doctoral students Myung Sung and Jaeseon Lee. Mudawar said, "Basically what we're doing is opening the window of opportunity in terms of heat dissipation, so that chip developers can make more aggressive chips, more demanding chips."

Mudawar's system uses hydrofluorocarbons, basically Freon a liquid used in air conditioners to cool air. The hydrofluorocarbons are piped through minuscule parallel channels in the chips which are covered with a metal plate. Tiny holes called microjets are cut into the metal plate and the hydrofluorocarbons are pumped into the channels to draw heat away from the chips. The heat produced by the chips causes part of the liquid hydrofluorocarbons to vaporize, which adds to the systems ability to cool. After the liquid-vapor combination leaves the chip it enters a cooling loop where it is turned back into a full liquid and returned to the chip to repeat the process.

This process is similar to a household air conditioner which uses compressed Freon to cool a coil which a fan blows air over. The coil cools the air which is fanned into the room. Mudawar's goal is to remove the greatest number of watts to keep the chip below 257 degrees Fahrenheit. As chips become smaller and more powerful there will be an increased need for heat removal in order to avoid a system meltdown.

The research has gained the attention of the Office of Naval Research, which has given the program about $500,000 in funding over the last four years. Mark S. Spector, the ONR's Program Officer for Advanced Naval Power Systems said that the research could be used for future military applications including high-power electronics found in lasers, propulsion and military sensor arrays. Spector said, ""The rapidly increasing use of electronics in military hardware is resulting in unprecedented thermal management needs." The Purdue team is still working the bugs out of the system, but hope to attract the attention of a military contractor.

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