A single boiling drop of coolant cooled a chip hot spot by up to 17°C in 15 seconds, University of Waterloo lab test shows
The idea could cut the cost of cooling AI data centers by using plain water for most of the heat. It has been tested only on a simulated chip.
Engineers at the University of Waterloo in Ontario, Canada, say aiming single drops of a special coolant at the hottest spots on a computer chip could make cooling AI data centers cheaper and more effective, according to a university news release Nov. 10.
AI data centers, like the large Google site planned in San Jose, pack thousands of powerful chips that turn electricity into heat. Some operators now sink electronics in tanks of coolant liquid, a method called immersion cooling. But small areas of a chip can heat up within seconds under heavy work, and coolant flowing past reacts too slowly, the university said. Hot spots slow chips down and make them wear out faster.
How it works
The team uses cheap deionized water, water with its minerals removed so it doesn’t conduct electricity, to carry away steady heat. For sudden spikes, it places a drop of a costlier electronics coolant that boils at a much lower temperature than water and is heavier, so it sinks and stays on the hot spot. Boiling soaks up heat, and the rising bubbles stir the water so it carries heat away faster.
“Water is excellent at handling steady, everyday heat and the drops take care of sudden spikes,” said Sushanta Mitra, a Waterloo professor of mechanical and mechatronics engineering.
In lab tests, one drop cooled a simulated chip hot spot sitting in a tank of water by up to 17°C (about 31°F) in 15 seconds, several times faster than ordinary immersion cooling, the university said. The researchers also wrapped drops in a thin skin of silicone oil with tiny ceramic particles to control how fast they boil.
Limits
The tests used a simulated chip, not servers in a real data center. The team envisions drops that drift through the water or are sent to hot spots found by sensors, but neither system has been built. The study appeared in the Journal of Colloid and Interface Science.