Researchers look to air-condition computer chips

Tag : Heat And Cool

Mudawar, who's leading the research, said the new cooling systemshould be able to cool chips that produce more than 1,000 watts ofheat for about every half-inch square of circuitry.
He said that would be a fivefold increase over the heat-removingabilities of existing systems that typically rely on air-cooling towaft heat away from microprocessors.
"Basically what we're doing is opening the window of opportunity interms of heat dissipation, so that chip developers can make moreaggressive chips, more demanding chips," Mudawar said.
The new cooling system uses tiny parallel grooves calledmicrochannels cut in a chip's surface and covered with a metalplate. Hydrofluorocarbons — a liquid used in air conditionersto cool air — are flushed through tiny holes in the metalplate called microjets and into the channels to draw heat away fromthe chip.
As it flows through the grooves, the liquid bubbles and partiallyvaporizes, adding to its ability to cool. After each pass, thefluid and vapor leaves the chip and enters a loop where it isreturned to an all-liquid state and then comes back into thechannels to cool again.
Personal computers get their brain power from conventionalmicroprocessors that rarely dissipate more than 100 watts of heatfor about every half-inch square. But computing systems needed forcomplex devices such as weapons systems generate far more heat.
And as chips used in those advanced computers become smaller andmore powerful, scientists must find a way to remove the additionalheat that puts those electronics at risk of a meltdown.
Mudawar said the goal is to remove the greatest number of watts— a measure of the rate of heat coming from a chip's surface— to keep it below a certain temperature. That's typically nogreater than 257 degrees Fahrenheit, he said.
Mudawar developed the new cooling technique with mechanicalengineering doctoral students Myung Sung and Jaeseon Lee.
The Purdue colleagues, who are still working to refine the system,hope their idea catches the interest of a defense contractor.
Some of their work was presented in May during a gathering inOrlando, of scientists who study ways of reducing heat in computerelectronics. Over the past four years, the Purdue team has receivedabout $500,000 in funding from the Office of Naval Research.
Mark S. Spector, the ONR's program officer for advanced naval powersystems, said the new research holds promise in the government'spush with academia and private industry to find new ways cool downmicroprocessors needed for future military applications.
He said those include the high-power electronics found in lasers,propulsion and military sensor arrays.
"The rapidly increasing use of electronics in military hardware isresulting in unprecedented thermal management needs," Spector said.