IBM isn’t the only one.
“We’ve been doing liquid cooling since 2012 on our supercomputers,” says Scott Tease, vice president and general manager of AI and high-performance computing at Lenovo’s infrastructure solutions group. “And we’ve been improving it ever since—we’re now on the sixth generation of that technology.”
And the liquid Lenovo uses in its Neptune liquid cooling solution is warm water. Or, more precisely, hot water: 45 degrees Celsius. And when the water leaves the servers, it’s even hotter, Tease says. “I don’t have to chill that water, even if I’m in a hot climate,” he says. Even at high temperatures, the water still provides enough cooling to the chips that it has real value.
“Generally, a data center will use evaporation to chill water down,” Tease adds. “Since we don’t have to chill the water, we don’t have to use evaporation. That’s huge amounts of savings on the water. For us, it’s almost like a perfect solution. It delivers the highest performance possible, the highest density possible, the lowest power consumption. So, it’s the most sustainable solution possible.”
So, how is the water cooled down? It gets piped up to the roof, Tease says, where there are giant radiators with massive amounts of surface area. The heat radiates away, and then all the water flows right back to the servers again.
Though not always. The hot water can also be used to, say, heat campus or community swimming pools. “We have data centers in the Nordics who are giving the heat to the local communities’ water systems,” Tease says.
