Data center rack density has risen rapidly in recent years. Operators are cramming more computing power into each server rack to meet the needs of AI and other high-performance computing applications. That means that each rack needs more kilowatts of energy, and ultimately generates more heat. Cooling infrastructure has struggled to keep pace.
“Rack densities have gone from an average of 6 kilowatts per rack eight years ago to the point where racks are now shipping with 270 kW,” says David Holmes, the global industries CTO at Dell Technologies. “Next year, 480 kW will be ready, and megawatt racks will be with us within two years.”
Corintis, a Swiss company, is developing a technology called microfluidics, in which water or another cooling liquid is channeled directly to specific parts of a chip to prevent overheating. In a recent test with Microsoft, servers running the company’s Teams video conferencing software recorded heat removal rates three times as efficient as other existing cooling methods.Compared to traditional air cooling, microfluidics lowered chip temperatures by more than 80 percent.
Boosting Chip Performance with Microfluidics
A lower chip temperature allows the chip to execute instructions more quickly, increasing its performance. Chips operating at lower temperatures are also more energy efficient and have lower failure rates. Further, the temperature of the air used for cooling can be increased, making the data center more energy efficient by reducing the need for chillers, and lowering liquid consumption.
The amount of water needed to cool a chip can be lowered considerably by targeting the liquid’s flow to the locations on the chip that are generating the most heat. Van Erp noted that the current industry standard is approximately 1.5 liters per minute per kilowatt of power. As chips are nearing10 kW, this will soon mean 15 liters per minute to cool one chip—a number that will raise the ire of communities worried about the impact of any supersized “AI factories” planned for their areas that could contain a million or more GPUs.
“We need optimized chip-specific liquid cooling, to make sure every droplet of liquid goes to the right location,” says Remco van Erp, the co-founder and CEO of Corintis.
Corintis’ founders Sam Harrison [left] and Remco van Erp hold a cold plate and microfluidic core, respectively. Corintis
The simulation and optimization software developed by Corintis is used to design a network of microscopically small channels on cold plates. Just like arteries, veins, and capillaries in the circulatory system of the body, the ideal cold plate design for each type of chip is a complex network of precisely shaped channels.
Corintis has scaled up its additive manufacturing capabilities to be able to mass-produce copper parts with channels as narrow as a human hair, about 70 micrometers. Its cold plate technology is compatible with today’s liquid cooling systems.
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