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Submerged IT – do you dare?

Liquid-immersion cooling is coming out of the realm of ‘black art’ and into the data center. Penny Jones looks at the industry developments behind this trend.

It is an area of data center cooling that has probably suffered most from its name. Marketing teams behind liquid-cooling inventions, while always guaranteed press coverage, have had a difficult time trying to persuade serious buyers to dunk their expensive hardware into a vat of green liquid.

Times may not have changed much - take-up is still small - but the coolants have made leaps and bounds, along with the solutions holding them. And more case studies have been coming out from real end-users.

On its Facebook page, manufacturing company Iceotope’s vertical approach to liquid cooling

3M, which has designed Novec, a gaseous fire-suppression agent now being used for liquid immersion of electronics, says: “It’s easy for newcomers to immersion to understand and even get excited about the thermal capabilities of the technology. What makes them shy away are the ‘black-art’ aspects that only a handful of people really understand.” It says more vendors are considering using its chemical solutions for immersion to address rising power densities.

Novec is used in a number of heat-transfer applications. The inert chemical coolant can be found in fire sprinklers for environments containing expensive equipment, such as museums, hospitals and banks, as it becomes a gas immediately after discharge.


Bull has launched a generation of direct liquid cooled (DLC) supercomputers that use liquid as close as possible to the server to draw heat. The firm says its bullx B700 DLC series systems can be used to cool up to 80kW per rack, compared with 40kW currently seen, by taking cooling inside the blade and reducing cooling needs outside of the cabinet.

Bull says it’s previous approach of liquid-cooling rack doors had brought PUE down to 1.4 without hardware modifications. The new option offers a high-density compute system with PUE of less than 1.1 under normal operating conditions, according to Bull.

In a press release, Bull said its research and development teams had to “radically” redesign the server to ensure it could be cooled using water at room temperature. “Cooling happens inside the blade itself, via direct contact between heat-generating components (processors, memory chips, etc.) and a cold plate in which heat-exchanger fluid is circulating,” Bull says.

Back in August 2011, 3M posted a video demo of an immersion server cluster – a four-node, eight-socket server chassis with 48AMD Opteron cores. It worked with AMD on the project, which demonstrated the ability to “hot- swap” server nodes without disruption to other servers. These nodes (a 600W load) were sitting in Novec 7100, which boils at about 60C.

ICEOTOPE DIPS SERVERS INTO NOVEC UK company Iceotope is using Novec for its liquid-cooled servers that were first patented in 2009. The new products are safer, according to Iceotope, as 3M assures that Novec liquid is non-flammable.

Iceotope has worked closely with Leeds University on its technology. Late last year its founder and CTO Peter Hoptom, who developed Iceotope’s technology, bought the company with a consortium backed by a seven-figure investment sum.

Iceotope said that in the data center, Novec can rapidly convect heat away from electronics, transferring it to a sealed low-pressure gravity fed tube system to provide 24/7 free cooling for ICT anywhere, anytime. The liquid can then be repurposed to heat other facilities.


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