AWS bets on liquid cooling for its AI servers
https://techcrunch.com/2024/12/02/aws-bets-on-liquid-cooling-for-its-ai-servers/

Microsoft ramps up plans to make its data centers less thirsty
https://www.theverge.com/2021/10/27/22747394/microsoft-data-centers-water-drought-climate-change-energy-emissions?scrolla=5eb6d68b7fedc32c19ef33b4

It’s turning to new technology to cool servers without using water

Microsoft ramped up its commitments today to conserve water and energy in its data centers, laying out new cooling tech and strategies that could push notoriously thirsty and energy hungry servers past their current limits. The company’s latest environmental pledge comes as it plans to dramatically expand the number of data centers it operates around the world, a move that could put more stress on drought-stricken communities unless the company finds ways to use less water.

Microsoft plans to slash the amount of water its data centers use by 95 percent by 2024, with the goal of “eventually” eliminating water use. That builds on a commitment it made last year to become “water positive” by the end of the decade, meaning it would replenish more water than it uses for its operations. In 2020, Microsoft also committed to becoming carbon negative by the same deadline, meaning it plans to draw down and store more planet-heating CO2 than it releases.

Microsoft also announced other sustainability efforts today that could lower greenhouse gas emissions inside and outside the company.

A typical data center uses about as much water as a city with a population of about 30,000 to 40,000 people, or about 3 to 5 million gallons of water a day, says Venkatesh Uddameri, professor and director of the Water Resources Center at Texas Tech University. Microsoft tells The Verge that its data centers use less water than that, although it varies across different regions and climates.

Microsoft’s data centers currently use adiabatic cooling, which relies on outside air to cool down temperatures inside. It’s a system that uses less electricity than air conditioning and less water than cooling towers. But when temperatures rise above 85 degrees Celsius, outside air isn’t very helpful. At that point, an evaporative cooling system kicks in, which uses water. It works like a “swamp cooler” — cooling the air by pushing it over or through water-soaked screens.

Microsoft today revealed two main strategies it plans to lean on to meet its water conservation goals. First: it researched how its servers perform under higher temperatures, and found that it can set higher limits for when the centers’ evaporative cooling systems kick in. In cooler parts of the world — including Amsterdam, Dublin, Virginia, and Chicago — those higher set points could, over the next few years, get rid of the need for water completely.

But Microsoft’s data centers in desert regions, where water scarcity is a bigger problem, will likely continue to guzzle water for years longer. Microsoft says the same strategy that might eliminate water use in Amsterdam and Dublin would only reduce water consumption in desert regions by as much as 60 percent by 2024.

That’s where the second part of Microsoft’s plan comes in. To get its water footprint down to zero in those hot and dry climates, Microsoft plans to turn to a new way to cool servers: submerging them in fluorocarbon-based liquid baths. As the servers work away, the heat they generate causes the liquid to boil when it reaches 122 degrees Fahrenheit (50 degrees Celsius). The boiling liquid moves heat away from the servers and then turns into a vapor that rises. The vapor hits a cooled tank lid, condenses, and rains back into the tub. The process, called two-phase liquid immersion, creates a closed-loop cooling system that cuts down on water and electricity use while getting rid of heat. It’s a strategy that the company says was inspired by cryptocurrency miners, who also use huge amounts of energy and have turned to liquid immersion cooling for computing equipment.