For an article I wrote a year ago, I interviewed Tom Furlong, director of site operations for Facebook’s data centers, along with Jay Park, the company’s director of data-center design and construction. We met in a construction trailer at the site of Facebook’s second company-owned-and-built data center, located near Forest City, North Carolina. At the time, construction of that data center was at a very early stage. The exterior walls of the 1100-foot-long building had just been lifted into place, the cavernous interior still largely empty. But construction continued on schedule, and Facebook announced yesterday that its Forest City data center was officially open.
Like Facebook’s first data center in Prineville, Oregon, the Forest City center doesn’t rely on conventional compressor-based air conditioners. Instead it uses what’s called air-side economization: Outside air is filtered, cooled by injecting a fine mist of water, and then blown through the data center to remove waste heat from the many racks of servers.
As a long-time North Carolina resident, I was stunned by the idea of cooling a whole data center in my state’s often hot and humid climate using what is essentially a giant swamp cooler. But Furlong and Park had carefully modeled the cooling system and were optimistic that it would work just fine. They had hedged their bets, though, by including conventional air-conditioning equipment as a back-up for when things just got too steamy.
It’ll be interesting to learn whether air-side economization suffices as summer arrives and temperatures climb into the triple digits. Given the company’s extraordinary openness about its technical operations, I might even be able to find out how often those back-up air conditioners get switched on by checking the Forest City data center’s Facebook page.