Is immersion cooling ready for mainstream?

“Immersion certainly lends itself more easily to new builds. I’m not saying it’s exclusive to new builds, but it certainly lends itself to new builds and modular and that’s because you can virtually eliminate air cooling all the infrastructure around that, and it makes the economics fairly, highly favorable,” Capes says.

The downside to immersion

But there are also drawbacks, not the least of which is getting the data center ready for the tanks. “I would have to think that preparing the data center for these tanks has to be a major undertaking,” said Abhijit Sunil, senior analyst with Forrester Research. He added that the immersion cooling is not something you can just add on to an existing data center infrastructure. “I think immersion cooling is better to consider on net new builds or retrofits.”

Sean Graham, senior analyst with IDC, said that a retrofit is required on any kind of liquid cooling. “That’s why there’s a short term popularity in rear door heat exchangers, because you can cool some of those higher densities without gutting the whole data center. Rear door cooling simply attaches directly to the back of the existing rack, you don’t need a redesign, you just need to be able to hook them up to the cooling agent,” he said.

Another problem is the space consumed, Sunil said. Tanks can be stacked as high as a standard datacenter rack and since their size varies from one vendor to the next, you may lose floorspace and wind up with lower capacity than you had expected.

Graham concurs. “I was in a data center that had liquid immersion cooling, and they lost about 50% of their floor space to cooling tanks,” he said.

For that reason, both recommend judicious use of immersion cooling for only the extreme conditions of high heat density, which is not going to be the entire data center, only a portion of it.

Adding to the challenge is that immersion is being done with hardware that was never meant to be dunked in liquids. “I think that probably one of the biggest challenges in the market up until now has been getting hardware that is immersion-optimized and warrantied,” said Capes.

The immersion cooling process involves dunking motherboards into the tanks of liquid, not a full chassis. HPE, Dell Technologies, and Lenovo don’t sell motherboards, they sell a rack enclosure. Ty Schmidt, vice president and fellow at Dell, says the company has an OEM business unit that works directly with its immersion cooling partners to take existing Dell servers and do what is needed to make the hardware work in an immersion system.

“From a validation qualification and warranty standpoint, it allows the guts of that system to be able to operate in said immersion cooling tank or technology. So, we have a dedicated team that owns that and does that on behalf of our partners and customers,” he said.

Immersion cooling growth potential

The market for immersion cooling is still in its infancy. Grand View Research puts the global immersion cooling market size at $197 million in 2022, anticipated to grow at a compound annual growth rate (CAGR) of 22.6% from 2023 to 2030.

Maurizio Frizziero, director of cooling innovation and strategy at Schneider Electric, said the real challenge is not technological, but cultural. IT managers just need to wrap their heads around the idea that they are going to dunk motherboards in liquid to cool them and not fry them.

“We believe that liquid cooling is a very viable way to go in a very sustainable way. Of course, we need to win the concern that any operator has on a new technology or new design guidelines,” he said, adding that Schneider sees immersion cooling and liquid cooling in general growing at a double-digit CAGR in the next three years.

Schmidt says he has noticed increasing interest from Dell customers in immersion as a solution to power constraints, since immersion uses the least amount of power of the cooling systems available.

“We understand what their power profile is and where it’s going to be in the future and what their facility constraints are. Immersion cooling may be a great solution for them. So, we have to understand both the customer constraints and environment as well as what’s happening in the industry to help guide that given customer, and the answer varies from customer to customer,” he said.

The big data center providers like Equinix and Digital Reality Trust are only now getting religion on immersion, said Capes. “We hadn’t gotten much support up until last six months. I can tell you that like the big guys are road-mapping immersion-ready servers on a two-year horizon. So, you can fully expect that within the next two years, you’re going to see the big players with air-cooled systems, direct-to-chip cooled systems, and immersion all side by side, and you’ll be able to pick and choose what you want,” he said.