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Cool Cooling: Jumping Droplets Whisk Away Hotspots In Electronics

Engineers from Duke University, backed by Intel and the National Science Foundation, have developed a new technology to cool hotspots in high-performance electronics by using  technology that was developed by mimicking the natural process that cicadas use to clean their wings.

Yes, you read that right, the very same process that allows a bug to clean its wings is now being used to cool hot spots in electronics. The super-hydrophobic surface of cicadas’ wings naturally repels water. This is possible because as two or more tiny water drops collide on the surface of the bug's wing, it creates a small amount of energy that in turn self-propels the newly formed water droplet into the air, taking trapped dirt and dust with it in the process.

Researchers, believing that this very same process could be utilized to remove waste heat from electronics, built a special vapor chamber with a super-hydrophobic floor and a sponge-like ceiling. As the chamber absorbs heat, condensation occurs in the areas directly under the hot spots, which, in turn forms tiny water droplets that fall to the super-hydrophobic surface of the chamber floor, forming larger drops.

The reduction in surface area causes the release of a small amount of energy that propels the larger drop into the air, taking heat energy with it. The heated "jumping" water drop is then absorbed into the sponge-like ceiling of the vapor chamber, and the cycle repeats itself. According to the article, this process happens regardless of orientation, even if the device is upside-down.

Researchers claim that the benefits of this type of cooling system has many advantages over existing cooling techniques. Thermoelectric cooling modules that use the Peltier effect are popular but are unable to target heat spots and are not particularly efficient. Although there are other cooling techniques capable of targeting hot spots, they require additional power inputs, which leads to inefficiencies.

This video from Duke University demonstrates how the entire process works:

Even though the engineers in charge of this project are optimistic, they freely admit there is still much work to be done before these jumping droplets can compete with today’s cooling technologies.

"It has taken us a few years to work the system to a point where it's at least comparable to a copper heat spreader, the most popular cooling solution," said Chuan-Hua Chen, associate professor of mechanical engineering and materials science at Duke. "But now, for the first time, I see a pathway to beating the industry standards."