Dielectric cooling for data centers

Until now, chips are mostly cooled thanks to air-cooling approaches: fans push air through heatsinks that sit on top of the chips to carry away excess heat. Liquid-cooling, which is more effective than air-cooling is more and more used.

In a 2017 study*, a team of IBM researchers developed a direct-attach cold-plate approach that enables the use of warm water at a temperature a few degrees above outdoor ambient to achieve lower chip junction temperatures than refrigerated air.

The authors demonstrate that this kind of approach involves a cooling energy reduction by over 90% and computational energy reduction of up to 14% compared to traditional refrigerated air-cooled data centers. It is not negligible since data centres in the US use about 70 million megawatts of electricity each year. It represents almost 2% of the country’s energy.

IBM, Georgia Tech and the Defense Advanced Research Projects Agency (DARPA) are now working on a program entitled Intrachip/Interchip Enhanced Cooling or ICECool program. A prototype was developed. Due to the electrical conductivity of water, it uses an insulating dielectric refrigerant to protect the chip. This coolant can come into contact with electrical connections, so is not limited to one part of a chip or stack. According to the researchers, this approach will lower the cost of cooling supercomputer CPUs by pumping refrigerants through microfluidic on-chip channels. This technology could help to cool off entire data centres. It is expected to appear in commercial products and military gear as soon as 2018.

* CHAINER T.J. et al. Improving data center energy efficiency with advanced thermal management. IEEE Transactions on components, packaging and manufacturing technology [online]. 2017, Vol. 7 Issue 8.
Available on: <http://bit.ly/NL72-ICECool> (Accessed 2017/12/11)