Many people know data centers use plenty of power, up to 2% of the world's electricity and growing 12% each year. But their impact on water is much more murky.
Against that backdrop, Facebook is reporting new data about its water efficiency, starting with its data center in Prineville, Oregon. The disclosure follows Facebook's detailed report about its renewable energy mix in late July.
The company is using a new industry measure - water usage effectiveness (WUE) - which specifically keeps tabs on the among of water used to keep the data center cool. It doesn't measure water consumption for plumbing or office purposes.
Over the past year, Facebook figures it has used an average of 0.22 liters of water per kilowatt-hour to keep the Prineville facility at an optimal operating temperature.
"We think that 0.22 L/kWh is a great result, but it should be noted that the WUE concept is fairly new and, to our knowledge, no one else has publicly reported WUE yet," Facebook writes in a blog. "We hope that other companies will soon start measuring and reporting WUE so we can begin setting benchmarks for the metric and working together to find new ways to improve."
The misting technology used in Facebook's data center helps cool water before it flows back into the data hall.
(Photo by Alan Brandt)
Facebook eventually plans to release the WUE metrics on a quarterly basis for all of its data centers; starting next with its second Prineville building and then focusing on Forest City, North Carolina.
Even if no one really knows what this number means yet, other technology companies or those with big information data center operations can take a cue from the best practices Facebook is using to keep water consumption at minimum.
Those practices include:
- Using outside area as a first stage of cooling, which eliminates traditional chillers and cooling towers. This minimizes how much water and energy must be used in the second stage of cooling, and it doesn't require chemical treatments to combat biological intrusions.
- Installation of an evaporative cooling misting system to reduce the temperature of air supplied to the data hall (see photo).
Facebook's heightened attention to water is part of its commitment to the Open Compute Project, an organization that advocates the creation of more energy efficiency technologies for servers and data centers. It published a detailed description of its data center cooling practices on the project's blog: