Green Data Centers Need Performance Not Prescriptions

Source: Flickr user torkildr

Standards make the IT world go ’round.  At the most basic level, they get all the parties in a given ecosystem on the same page, ensuring interoperability for the market’s participants. So why would Google oppose ASHRAE cooling standards that promote energy efficiency for data center cooling?

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) is in the midst of revamping its 90.1 standard for a building’s efficiency. Erect a commercial building in the U.S., and there’s a very good chance that the standard influenced the building codes that govern its construction. Before the changes, data centers were exempt. Inclusion, while new, is not what concerns Urs Hoelzle, Google’s senior VP of operations.

In a letter posted in the Google Policy Blog — and signed by his counterparts at Microsoft and Nokia among other IT heavy hitters — Hoelzle spelled out the main gripe with ASHRAE’s proposed changes to the standard. The sticking point? In the revised standard, ASHRAE would require data centers to use economizers.

Economizers rely on outside air to help cool a facility, drastically reducing energy consumption compared to operating the chillers on conventional cooling systems. When you hear that a facility is “free-cooled,” an economizer is involved — incidentally, Google is a big supporter of this cooling technique. So what’s so bad about requiring the use of economizers?

Hoelzle described the mandate as “prescriptive” and not necessarily a good fit for all data center operators. He’s absolutely right. The U.S. is a vast territory, with extremes in temperature and climate, from blistering temps in the South to near-Arctic conditions in the North. Economizers, for instance, make perfect sense in northern climes, but their effectiveness wanes the further south they’re deployed. And this week, Iceland’s ash clouds, like Australia’s massive dust storm last year, are renewing concerns about how air quality impacts the air handling and filtering elements of economizer-based cooling systems.

ASHRAE is already backtracking somewhat, saying it welcomes more feedback and that the group will allow for exceptions and is considering alternate options for benchmarking data center efficiency, such as PUE (power usage effectiveness). Chris Malone, Thermal Technologies Architect at Google, opposes incorporating PUE into the ASHRAE standard, pointing out that PUE encompasses the power used by an entire facility, not just its cooling system. Yet PUE may be a step in the right direction.

When it comes to data centers, ASHRAE has to rethink its approach. Instead of a “checklist” mentality, where the presence of a particular technology dictates a facility’s “greenness,” ASHRAE should take an achievement/performance-based view of its standards.

That’s the approach The Green Grid has taken in pushing PUE as a metric for data center efficiency. Sure, PUE has its detractors, but there’s been no big industry outcry. On the contrary, it has just become an international standard. Why? Because PUE, at its core, is a performance-based measure of how efficiently a data center uses its electricity. The technology the data center operators employ to lower their PUE ratings — lower is better — doesn’t matter. What does matter is that companies are exploring and implementing innovative techniques and technologies to bring their scores down as close to a 1.0 as possible.

If the economizer checkbox is filled, where’s the incentive to pursue other avenues to efficient cooling?

That’s the crux of Google et al.’s argument against the economizer rule. Fundamentally, technology companies live and die by measures of performance and the competitive landscape that emerges as a result. From the Top500 list of supercomputers to TCP benchmarks, success comes from constant one-upsmanship and the innovative technological strides that result from the wide latitude they’re given in their efforts to reach the top. My hunch is that for green data centers, the same applies.

Question of the week

Should ASHRAE simply drop the economizer requirement?