Intel and SGI cool servers by dunking them
Intel and SGI have been testing a supercomputer that’s kept cool by submerging the electronics completely in fluid, a system they say can dramatically reduce energy bills.
The companies built a proof-of-concept supercomputer that’s kept cool using a fluid developed by 3M called Novec. It’s a dielectric liquid, which means electronics can be submerged in it and continue to operate normally.
Novec is already used in fire suppression systems, and Intel and SGI are now testing its viability as a more efficient cooling system for computers, where they say it could replace fans and eliminate the need to use tons of municipal water to cool data centers.
The technology has the potential to slash data-center energy bills by more than 90 percent, said Michael Patterson, senior power and thermal architect at Intel. But there are several challenges, including the need to design new motherboards and servers.
One current challenge for all types of data centers is that they’re running low on space and finding it hard to generate enough airflow to cool increasingly powerful servers.
“I can see something like this—after it has been refined and automated—providing data centers with higher levels of capacity with a smaller energy footprint,” Patterson said.
The idea is akin to putting a motherboard on ice. The Novec fluid surrounds the hardware and absorbs heat, keeping the CPU and other components at a constant temperature.
The companies are demonstrating the proof-of-concept system, an SGI Ice X distributed memory supercomputer, at a 3M office in St. Paul, Minnesota. The Intel Xeon chips are submerged directly in the fluid.
They’re not the only companies experimenting with Novec. Intel is also working with Iceotope on a different full-immersion design.
It could solve a big problem - that of companies needing to reduce their energy bills even as they buy more powerful computers—but it could also require ripping up traditional server and motherboard designs.
“It’s an opportunity and a problem at the same time,” Patterson said. Servers have historically been designed to maximize the flow of air over components, and immersion cooling is a very different concept.
On today’s motherboards, circuits are laid out just the right distance apart to maximize heat dissipation. With Novec, circuits could be packed together much more tightly, but redesigning servers is a big undertaking.
The companies also need to rethink rack-level interconnects, since plunging today’s optical cables directly into Novec might not work, Patterson said.
SGI has customers ready to try out the technology, and based on their feedback it will experiment with new computer designs, said Bill Mannel, SGI’s general manager of compute servers.
Intel is not making any immediate changes to its chip road map, but it may need new products to support the cooling technique in the future.
“I don’t anticipate that there would be a reduction of circuitry, but there will be changes to platform power and thermal management modules,” Patterson said.
Joe Koch, a business director at 3M, likened Novec to a large liquid heat sink. As the server components heat up, properties of the liquid allow it to absorb the heat without becoming superheated itself.
Novec can help CPUs operate at a consistent temperature, which Patterson said can help reduce electrical leakage on chips. Direct-contact cooling may also allow Intel to pack electronics much more densely, he said.
“Sometime in the future we’re going to look at ‘stacked silicon,’ where air cooling just won’t work,” he said. “Novec is something that can get to 3D stacking.”
To test Novec, the companies are also working with the U.S. Naval Research Laboratory, Lawrence Berkeley National Laboratory and equipment maker Schneider Electric.
It could be a while before companies are buying immersion-cooled servers, but Intel thinks the technology may have a future.
“We wouldn’t have done this if we didn’t believe it had potential,” Patterson said. “That’s why we’re taking this to the next step and learning more about Novec.”