Immersion-2: Liquid Cooling Designed for 100kW Racks


This custom piping system supports a liquid immersion cooling system powering a Bitcoin mining data center in Hong Kong. (Photo: Allied Control)

How do you create a 500kW data center that can run inside a high-rise office building? That’s what Allied Control recently did in Hong Kong, where it created a data center that housed custom Bitcoin mining rigs in a rack-mounted immersion cooling system. We’ve previously noted the project as a novel implementation of high-density cooling for ASIC-based systems for validating Bitcoin transactions. With the proof-of-concept up and running, Allied Control is now marketing the design – known as Immersion-2 – as a container-based approach for ultra high density cooling, supporting loads of 18kW to 225kW a rack.

That’s not a typo: Allied Control says these units can support up to 225 kW in critical load in a single rack. The current 500kW installation is spread across 24 racks, with three cooling tanks per rack. Allied Control says the tanks are currently just 30 percent full, and the entire 500kW of capacity could be housed in five racks if they sought to consolidate them at 100 kW per rack. The companys says there is considerable potential for even higher density using this design.

“In order to accommodate a possible increase in capacity, we have built a simple closed loop water circuit,” writes in a blog post providing a technical overview. “When sizing the flow, pipe size and other properties of the circuit, our engineers intentionally went “a couple of sizes larger” than what is technically required.

Within the facility, rows of rack-mounted tanks are filled with Novec, a liquid cooling solution created by 3M. Inside each tank,densely-packed boards of ASICs (Application Specific Integrated Circuits) run constantly as they crunch data for creating and tracking bitcoins. As the chips generate heat, the Novec boils off, removing the heat as it changes from liquid to gas. The initial system was built in a 19-inch server rack form-factor, but other shapes and sizes are available. Here’s a video from Allied Control showing the immersion cooling units in action, as well as the piping system that supports the tanks. It’s a very different vision of the data center.

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About the Author

Rich Miller is the founder and editor at large of Data Center Knowledge, and has been reporting on the data center sector since 2000. He has tracked the growing impact of high-density computing on the power and cooling of data centers, and the resulting push for improved energy efficiency in these facilities.

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  1. Air cooling, I'd like you to meet your demise... This is a fundamental game changer and here is why - it lifts the thermal barrier of chip designs, not just for ASICs either. I wonder if Moore's law gets compressed from 2 years to 1 year since the next generation of chips do not have to factor in thermal limitations any longer. If we think about computer power as it relates to design, I have WAY more computing power in my pocket than I had on my first personal computer - a Commodore VIC20. Computers get smaller, use more power, and since computers turn electricity into heat - thermal management is key. The market for Allied Control is larger than Bitcoin. Much larger, although Bitcoin is a solid proving ground for this given the architecture of the mining rigs and their density (2.2-2.4 Kw per rig) and challenges keeping the rigs cool enough to operate and if in a multi tenant environment, dissipate heat from one box that is the former equivalent of one cabinet. That is a lot of heat for air cooling to manage. It can be managed, but at what cost? In a study Blunt Hammer did last year, we found that 30Kw a cabinet was the very distinct dividing line on density - you could either cool 30Kw/cabinet or you couldn't. Allied Control takes it to a new level. A big market challenge is that to adopt the new technology means an operator must strand millions of dollars of infrastructure investment with the air cooled approach and that could be a tough pill to swallow for a target market if the target market is a rip and replace of air cooled infrastructure. They could absorb a liquid cooled solution over time, but if you have 1M square feet of building with 100MW that you now can cool the 100Mw in less than 10,000 square feet, what do you do with the other 990,000 square feet you paid for or that your investors used to de-risk an investment? It breaks the real estate model and pushes data centers into utility scale - small facilities everywhere with very dense capabilities. That is 4 racks per MW folks which many wholesale providers put in a 10,000 square feet room. For 2,000 MW, that is 8,000 racks in 50,000 square feet (6.25 feet per rack). That does more than break the real estate model, it disintegrates it... Investors, grab your phasers and let's go disintegrate something...

  2. Data Center and IT room high temperature discharge is one of the greatest crucial yet least implicit of all demanding IT environment processes. Thanks for the read Rich. amazing insight.

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