Microsoft shares new data center design featuring a closed-loop water system for cooling

Microsoft revealed details of new approach to cooling data centers that won’t lose water to evaporation.

The strategy will still use water, but it’s contained in a closed-loop system where it flows past heat-generating processing chips, drawing off heat that it carries to chillers. Then the cooled water starts the journey all over again.

Microsoft data centers gulped down roughly 33 million gallons of water per center in the last fiscal year, according to company estimates. But that number used to be even higher. The cloud computing company has been working to cut its water use, paring it down 39% since 2021.

Microsoft operates 300 data centers worldwide, and that number continues to grow as expanded use of artificial intelligence and generative AI require additional computational power.

The tech giant’s other water-saving strategies include adjustments to the temperatures at which the centers operate and using reclaimed and recycled water at sites in Washington, California, Texas and Singapore.

Microsoft will begin deploying the closed-loop technology, which it calls zero-water evaporated designs, at new projects being built in Phoenix and Mt. Pleasant, Wis. Its water use has raised concerns in local communities, including a center being built in Goodyear, Ariz., that was highlighted in a March report in The Atlantic.

In June, the Redmond, Wash.-based company released its Datacenter Community Pledge in which it vows to “design and operate our datacenters to support society’s climate goals and become carbon negative, water positive and zero waste before 2030.”

The new cooling technology will create a “nominal” increase in energy use, according to Steve Solomon, Microsoft’s vice president of datacenter infrastructure engineering.

Microsoft has committed by next year to purchase 100% renewable energy worldwide to match its power use. But that pledge means that in real time it will sometimes be using fossil fuel power when renewables aren’t available. So three years ago, it upped the ante and vowed to use clean energy 24/7 by 2030. Google has made a comparable commitment.

Data center hyperscalers such as Microsoft are scrambling to secure round-the-clock, clean energy sources. The company has a deal with fusion company Helion Power to get electricity from a yet-to-be-built fusion reactor, provided Helion can successfully get power to the grid. And it has an agreement to help restart a nuclear reactor at Pennsylvania’s Three Mile Island, among other efforts.