Facebook boldly predicts PUE of 1.15 for future data center

Using energy-saving techniques such as free cooling, Facebook's first data center could be among world's greenest

Facebook broke ground this week on its first custom data center in Prineville, Ore., a facility that the company says will be so energy efficient, it will have a PUE (Power Usage Effectiveness) of 1.15.

PUE, a measurement made popular by The Green Grid, calculates how much energy a data center uses for actual work (i.e. computing) versus how much is wasted on non-productive tasks like cooling machines or through heat waste. At a data center with a PUE of 1.8, for example, for every 1.8 watts that go through the utility meter, 1 watt is delivered to the computer infrastructure.

[ The Uptime Institute cautions that PUE measurements should be taken with a grain of salt. | Did your organization undertake an innovative green-tech project in 2009? InfoWorld is currently accepting nominations for the 2010 InfoWorld Green 15 awards. ]

Were Facebook's future data center to achieve a PUE of 1.15, it would be among the most energy efficient in the country. The average data center has PUE of around 2.0 or higher, according to an EPA report from 2006; that figure should drop to 1.9 by 2011. Google, which claims to have some of the greenest data centers on Earth, boasts an average trailing PUE of 1.19 for its various data centers with a load of 5MW of higher. The lowest PUE the company has achieved at a single facility is 1.11.

[ Learn six techniques Google employs to make its data centers greener.]

According to Facebook VP of technical operations Jonathan Heiliger, Facebook plans to achieve its remarkably low PUE through several energy-saving techniques. Among them, Facebook will use an airside economizer between 70 and 80 percent of the time to cool the facility with outside air. This technique is also known as "free cooling." The rest of the time, the facility will employ an evaporative cooling system, which evaporates water to cool incoming air, rather than using a more energy-intensive traditional chiller system.

Facebook reports that it will reuse server heat to keep offices toasty during the colder months. Additionally, the company says it's adopting a proprietary UPS (uninterruptable power supply) technology that reduces electricity usage by as much as 12 percent.

The company makes no specific mention of what type of hardware or other IT tools it will use to reduce energy consumption. Google, for example, claims to cut electricity waste by using servers that have been stripped of any superfluous components that waste energy.

Beyond employing techniques that will increase the data center's energy efficiency, Facebook is also designing the facility to achieve LEED (Leadership in Energy and Environmental Design) Gold-level certification. (The highest level of LEED certification is Platinum, achieved by organizations such as Citi and Digital Realty Trust.)

This story, "Facebook boldly predicts PUE of 1.15 for future data center," was originally published at InfoWorld.com. Follow the latest developments in green IT at InfoWorld.com.

Copyright © 2010 IDG Communications, Inc.

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