Microsoft gets two-phase immersion cooling in Azure data center

Microsoft says it is the first major cloud provider to test and implement two-phase liquid immersion cooling in its data centers.

Microsoft has been testing biphasic liquid immersion cooling technology for several years. Now it is starting to implement the technology in its Azure data centers, starting with those based in Quincy, Washington, officials said on April 6.

This deployment in the two-phase immersion cooling production environment is the next step in the company’s journey to provide more powerful, reliable and environmentally friendly data centers, officials said.

Like other major cloud providers, Microsoft uses air to cool processors that get hotter, especially when running certain workloads. Because heat transfer in liquids is “an order of magnitude more efficient than air,” immersion cooling could be a much better solution over time, according to executives.

Google has already deployed liquid cooling in its data centers to handle high-power demands from its Tensor AI processing unit. Microsoft claims to be the first to revolve around the “two-phase” part of immersion cooling.

With single-phase cooling, the fluid remains in a liquid state and the heat is transported by natural or forced convection. In this respect, monophased cooling is like air cooling. The hot fluid in turn releases heat through a heat exchanger and is returned, company officials say. But biphasic cooling occurs passively. When the fluid comes into contact with heat-generating components, the fluid changes state of steam liquid and naturally rises, carrying heat in the form of latent energy. Steam releases heat at the level of a condenser and naturally transforms into liquid form, Microsoft executives said.

The cryptocurrency/bitcoin mining industry was a great pioneer of liquid immersion cooling, using it to cool chips recording transactions in digital currency. Microsoft has studied liquid immersion cooling for high-performance workloads such as AI and has found that cooling by biphase immersion can reduce a given server’s energy consumption by between 5% and 15%, officials said. Servers can be overloaded (run at high power) when needed without the risk of overheating.

Liquid cooling is a water-free technology. Quincy’s steel cooling tank is filled with a technical solution that allows servers to be soaked in liquid and function as they would in any standard air-cooled rack. The liquid boils at 122 degrees F (90 degrees colder than boiling water). The coils that pass through the tank and allow steam to condense are connected to a separate closed-loop system that uses a fluid to transfer heat from the tank to a dry cooler outside the container that houses the tank.

For now, Microsoft has a tank running loads of workloads in a large-scale Azure data center. Over the next few months, the Microsoft team will conduct a series of tests on the technology.

“Intensive computing has been using this type of technology for decades, so the risk is not really high,” said Christian Belady, Microsoft’s distinguished engineer, also vice president of Datacenter Advanced Development. “The goal is for us to deploy this in all regions of our data centres, but there are a number of steps before we get there.”

Belady noted that the work of Microsoft’s “Project Natick” underwater data center has demonstrated the improved reliability of systems when moisture and oxygen are removed from an environment. Corrosion failures decrease significantly.

“With immersion, you have a similar thing. Essentially, you move oxygen and moisture,” he said.

Microsoft continues to study other liquid cooling technologies, including cold plate, which typically relies on tubes filled with a liquid refrigerant. Belady says Microsoft sees a potential opportunity for both, but since immersion is “a unique design cost for infrastructure,” with no engineering required between generations of servers, it can find more widespread use.

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