"Hotspot cooling is important for high performance technologies," said associate professor Chuan-Hua Chen. "A better cooling system will enable faster computers, longer-lasting electronics and more powerful electric vehicles."
According to the researchers, when water droplets merge, the reduction in surface area causes the release of a small amount of energy. So long as the surface beneath is hydrophobic enough to repel water, this energy is sufficient to make the merged droplet jump away.
The technology relies on a vapour chamber made of a super-hydrophobic floor with a sponge-like ceiling. When placed beneath operating electronics, moisture trapped in the ceiling vaporises beneath emerging hotspots. The vapour escapes toward the floor, taking heat away from the electronics.
Passive cooling structures integrated into the floor of the device then carry away the heat, causing the water vapour to condense into droplets. As the growing droplets merge, they naturally jump off the hydrophobic floor and back up into the ceiling beneath the hotspot, and the process repeats itself. This is said to happen independently to gravity and regardless of orientation.
The research team claims the technology has many advantages over existing cooling techniques. Thermoelectric coolers cannot target random hotspot locations, making them inefficient for use over large areas. Other approaches can target moving hotspots, but require additional power inputs, which also leads to inefficiencies.
The jumping-droplet cooling technology also has a built-in mechanism for vertical heat escape, which is said to be a major advantage over today's heat spreaders that mostly dissipate heat in a single plane.
