Waterloo team cools AI chip hotspots with a single drop: 17°C in 15 seconds

Researchers at the University of Waterloo in Canada have developed a new cooling method for overheating chips in artificial intelligence data centres: inexpensive deionized water handles general immersion cooling, while a single drop of a specialized coolant that boils on contact targets sudden hotspots on the chip. In lab tests, one drop cut the temperature of a simulated hotspot by 17°C in 15 seconds, several times faster than conventional immersion cooling. The findings were published in the Journal of Colloid and Interface Science and announced by the university on November 10.

Water for everyday heat, coolant drops for hotspots

The team is led by Dr. Sushanta Mitra, a professor of mechanical and mechatronics engineering and executive director of the Waterloo Institute for Nanotechnology, with postdoctoral researcher Dr. Tian-Yu Zhang and PhD student Arnav Banerjee. A simulated chip is submerged in deionized water, and a drop of the electronics coolant Novec 7100 — which boils at a much lower temperature than water and is denser, so it stays put on a hotspot — is placed on its surface. When the drop boils, it absorbs a large amount of heat. The team also wrapped the drops in a thin skin of silicone oil using an encapsulation technique, to control when and how bubbles form.

Still at the lab stage, with no real hardware tested

At the highest tested heat flux, 14.4 watts per square centimetre, an uncoated drop cooled the centre of the simulated hotspot by about 17°C within 15 seconds. The researchers envision two ways the system could ultimately work: coolant drops circulating through the water and activating when they hit a hotspot, or drops delivered directly to hotspots detected by sensors. The work remains at an early stage — it has been tested on a single simulated chip only, with no demonstration yet around real electronic components, and no published figures on cost, long-term reliability or environmental impact. Deployment is still some way off.