A patented passive cooling system for computers, which does away with fans and a chunk of wiring, is so efficient, it could save U.S. consumers more than $6.3bn per year in energy costs.
The system, which was awarded $10,000 in 2014 via the University of Alabama, Huntsville’s (UAH) Charger Innovation Funds, uses convection technology to circulate 3M’s Fluorinert FC-72 liquid through channels in a computer’s processor and then into a heat sink that acts as the computer’s external radiator.
Foregoing fans and the wires needed to connect that particular component, industry experts predict this approach could save computer manufacturers $540 million annually in manufacturing material costs.
Dr. James E. Smith Jr., a UAH chemical engineering professor emeritus who is working with graduate students to optimize the system, believes the system’s true value will be seen when it reaches the global scale. “If you can do this for the world, we can save a whole lot of pollution globally,” Dr. Smith says. “Think of what could be done in China alone.”
Regarding the group’s approach, 3M’s Fluorinert FC-72 is an electronic cooling liquid and electrical insulator. A bit more specifically, it is colorless, odorless, biologically inert, and a chemically stable dielectric liquid that is nonflammable and has a boiling point of 133 degrees Fahrenheit, 56 degree Celsius.
When the system is in use, heat from the computer processor vaporizes the FC-72, whereupon the light vapor moves to a heat exchanger. Here, the heat is released into the environment and condenses into a heavier liquid. It then moves to a holding tank before the liquid eventually travels to the processor again to complete the cycle.
Student Cuong Nguyen, who worked on this system with Dr. Smith, explained that for his chemical engineering master’s thesis, he compared the passive cooling system with traditional solid-state passive cooling and traditional fan cooling in computers that ran for up to 12 hours under no load and heavy load conditions. The systems were tested using modified Intel Pentium 4 and Core i3 processors. Nguyen discovered that a near steady state 56-degree Celsius processor operating temperature was achieved using the passive cooling system. The acceptable range of processor operating temperature is 50 to 90-degree Celsius.
“Our system can absolutely work, and it can work for 12 hours in a stable condition,” Nguyen says. He went on to explain some of the additional physical benefits of having a passive cooling system in place of a fan-based one. “When we remove the cooling fan, it saves material costs, but it also eliminates the noise, vibration and dust contamination of fan cooling,” he explains. “When you remove the dust, you remove the chance that it can build up. Build-up of dust can destroy the electronic components.”
Beyond computer usage, optimized liquid passive cooling has plenty of other applications to which it can be applied. For instance, the system could be used in temperature stabilization of electronic guidance and propulsion control technologies in space; it could also serve as part of a more efficient power delivery system.
“When you look at the power transistors required for the smart grid, for example, this system could have application there, and there are other applications in that area, too,” says Dr. Smith. “Wherever you want to make high power in a small area, that is a potential application.”
The system is presently undergoing optimization enhancements at UAH.
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