What with the Internet's popularity, creation and use of data centers has taken off in the last two decades to the point that they now account for 2 percent of energy consumption worldwide. Because of their growth, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers set some restrictions for how data centers are cooled, hoping to keep their emissions under control. But some companies, including Google, have taken issue with ASHRAE's methods-based approach, and are petitioning for changes.

In Standard 90.1 of its building codes, ASHRAE sets forth requirements on what equipment companies can use to cool their data centers. The standard requires companies' data centers to be be cooled with economizers, which direct ambient air in a specific flow, and prevents use of other approaches, such as air conditioners.

Google responded to the standard in a post on their public policy blog this week, undersigned by other companies like Microsoft and Amazon. They felt the ASHRAE standards should be based on efficiency, rather than approach—if it can achieve a set efficiency threshold, the search giant asks, does it matter how it's done? Google invokes the case of car emissions, noting that cars must achieve a certain minimum gas mileage, but don't have to use a particular type of engine.

Google acknowledges in its post that economizers are very efficient and emission-friendly, but new and possibly better methods for cooling are still being invented. For example, a perspective published in Science this week detailed how data centers might be sufficiently cooled even with relatively warm water, up to 70 ºC. Using warm water would mitigate some of the mechanical costs of liquid cooling and would lose the refrigeration that cold-water systems use.

ASHRAE is open to suggestions on the matter, and have a proposed addendum to Standard 90.1 in the works that is available for public viewing. The addendum places limits on the efficiency and BTUs per hour that various types of cooling systems may use, and takes away the restrictions on air conditioners, water coolers, and economizers. ASHRAE will continue to take comments on the addendum until April 19.

Science, 2010. DOI: 10.1126/science.1182769 (About DOIs).