Immersion-2: Liquid Cooling Designed for 100kW Racks

bitcoin-allied-asicminer

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.