IBM’s new data center offers bold new ideas about how to cool servers. It has long been taken for granted that the best way to control the temperature in a server room was to keep it as cool as possible by blowing out the heat generated by processors inside the servers with chassis fans. IBM’s new data center in Zurich, Switzerland uses liquid cooling to do the same job. In a previous post, I talked about liquid cooling as an alternative to air cooling, but the new data center in Zurich is unique: it’s cooled by hot, not cold, water.
As described in an article on ServerWatch.com, a new idea is emerging in the server industry about how to moderate the heat produced by running servers. Instead of controlling the temperature of the server room itself, it’s much more important to focus on cooling the server components, regardless of how high the temperatures rise in the server room. Recent innovations in air cooling, such as allowing air from outside the building to be cycled through the server room even in locations as hot as New Mexico, show that a hot server room by itself does not dampen the performance of the servers.
But CPUs overheating does. The new Zurich data center, unlike previous liquid-cooled clusters, uses water at 140 degrees F to cool CPUs that run at 185 degrees F. It’s not necessary to chill the water, IBM reasoned, because even warm water is much colder than the temperature of the processors that it heats. So, to save money, the Zurich data center does not chill the water, and moreover pumps it (once it’s been boiled by the servers) to help heat nearby homes.
According to EnterpriseITPlanet.com, “The combined carbon reduction from using less electricity to cool the servers to the recaptured heat for heating purposes is a whopping 85 percent.” As equally important, IBM saved about 40% on their energy spending by switching to hot-water cooling of their servers.
The bottom line, it seems to me, is summed up by Jed Scaramella, senior research analyst for IDC’s Enterprise Platforms and Datacenter Trends as quoted in the ServerWatch article, when he said, “if you walk into the room and the room is cold, that doesn’t tell you much [about how well the servers are cooled]”.