There’s little question that AI data centers require liquid cooling, as AI workloads drive ever-increasing rack densities. So, coolant selection, fluid management, and cooling system reliability all become paramount. It’s natural, then, that questions arise about the most common cooling fluid, PG25, as well as what ASHRAE and the Open Compute Project (OCP) recommend.
In this blog post, I’ll tackle some of the most common coolant questions we hear from hyperscalers, colocation providers, neoclouds, and other data center ecosystem players.
Let’s start with a basic question: What coolant should I use for data center liquid cooling?
Companies have three main fluid options for liquid data center cooling: dielectrics, deionized water plus additives, and PG25. Dielectrics are used mainly for immersion cooling, which really can’t keep up with the increasing cooling requirements of AI chips.
Deionized (DI) water performs well, but the maintenance required to keep the fluid clean can significantly increase costs. The industry has thus settled on PG25, which performs nearly as well as DI water but with far less fluid maintenance.
