Immersion cooling to offset data centers' massive power demands gains a big booster in Microsoft

Jonathan Shieber
·6 min read

LiquidStack does it. So does Submer. They're both dropping servers carrying sensitive data into goop in an effort to save the planet. Now they're joined by one of the biggest tech companies in the world in their efforts to improve the energy efficiency of data centers, because Microsoft is getting into the liquid-immersion cooling market.

Microsoft is using a liquid it developed in-house that's engineered to boil at 122 degrees Fahrenheit (lower than the boiling point of water) to act as a heat sink, reducing the temperature inside the servers so they can operate at full power without any risks from overheating.

The vapor from the boiling fluid is converted back into a liquid through contact with a cooled condenser in the lid of the tank that stores the servers.

“We are the first cloud provider that is running two-phase immersion cooling in a production environment,” said Husam Alissa, a principal hardware engineer on Microsoft’s team for datacenter advanced development in Redmond, Washington, in a statement on the company's internal blog.

While that claim may be true, liquid cooling is a well-known approach to dealing with moving heat around to keep systems working. Cars use liquid cooling to keep their motors humming as they head out on the highway.

As technology companies confront the physical limits of Moore's Law, the demand for faster, higher performance processors mean designing new architectures that can handle more power, the company wrote in a blog post. Power flowing through central processing units has increased from 150 watts to more than 300 watts per chip and the GPUs responsible for much of Bitcoin mining, artificial intelligence applications and high end graphics each consume more than 700 watts per chip.

It's worth noting that Microsoft isn't the first tech company to apply liquid cooling to data centers and the distinction that the company uses of being the first "cloud provider" is doing a lot of work. That's because bitcoin mining operations have been using the tech for years. Indeed, LiquidStack was spun out from a bitcoin miner to commercialize its liquid immersion cooling tech and bring it to the masses.

"Air cooling is not enough"

More power flowing through the processors means hotter chips, which means the need for better cooling or the chips will malfunction.

“Air cooling is not enough,” said Christian Belady, vice president of Microsoft’s datacenter advanced development group in Redmond, in an interview for the company's internal blog. “That’s what’s driving us to immersion cooling, where we can directly boil off the surfaces of the chip.”

For Belady, the use of liquid cooling technology brings the density and compression of Moore's Law up to the datacenter level

The results, from an energy consumption perspective, are impressive. The company found that using two-phase immersion cooling reduced power consumption for a server by anywhere from 5 percent to 15 percent (every little bit helps).

Microsoft investigated liquid immersion as a cooling solution for high performance computing applications such as AI. Among other things, the investigation revealed that two-phase immersion cooling reduced power consumption for any given server by 5% to 15%.

Meanwhile, companies like Submer claim they reduce energy consumption by 50%, water use by 99%, and take up 85% less space.

For cloud computing companies, the ability to keep these servers up and running even during spikes in demand, when they'd consume even more power, adds flexibility and ensures uptime even when servers are overtaxed, according to Microsoft.

“[We] know that with Teams when you get to 1 o’clock or 2 o’clock, there is a huge spike because people are joining meetings at the same time,” Marcus Fontoura, a vice president on Microsoft's Azure team, said on the company's internal blog. “Immersion cooling gives us more flexibility to deal with these burst-y workloads.”

At this point, data centers are a critical component of the internet infrastructure that much of the world relies on for... well... pretty much every tech-enabled service. That reliance however has come at a significant environmental cost.

“Data centers power human advancement. Their role as a core infrastructure has become more apparent than ever and emerging technologies such as AI and IoT will continue to drive computing needs. However, the environmental footprint of the industry is growing at an alarming rate,” Alexander Danielsson, an investment manager at Norrsken VC noted last year when discussing that firm's investment in Submer.

Solutions under the sea

If submerging servers in experimental liquids offers one potential solution to the problem -- then sinking them in the ocean is another way that companies are trying to cool data centers without expending too much power.

Microsoft has already been operating an undersea data center for the past two years. The company actually trotted out the tech as part of a push from the tech company to aid in the search for a COVID-19 vaccine last year.

These pre-packed, shipping container-sized data centers can be spun up on demand and run deep under the ocean’s surface for sustainable, high-efficiency and powerful compute operations, the company said.

The liquid cooling project shares most similarity with Microsoft’s Project Natick, which is exploring the potential of underwater datacenters that are quick to deploy and can operate for years on the seabed sealed inside submarine-like tubes without any onsite maintenance by people.

In those data centers nitrogen air replaces an engineered fluid and the servers are cooled with fans and a heat exchanger that pumps seawater through a sealed tube.

Startups are also staking claims to cool data centers out on the ocean (the seaweed is always greener in somebody else's lake).

Nautilus Data Technologies, for instance, has raised over $100 million (according to Crunchbase) to develop data centers dotting the surface of Davey Jones' Locker. The company is currently developing a data center project co-located with a sustainable energy project in a tributary near Stockton, Calif.

With the double-immersion cooling tech Microsoft is hoping to bring the benefits of ocean-cooling tech onto the shore. “We brought the sea to the servers rather than put the datacenter under the sea,” Microsoft's Alissa said in a company statement.

Ioannis Manousakis, a principal software engineer with Azure (left), and Husam Alissa, a principal hardware engineer on Microsoft’s team for datacenter advanced development (right), walk past a container at a Microsoft datacenter where computer servers in a two-phase immersion cooling tank are processing workloads. Photo by Gene Twedt for Microsoft.