Data centers suck down energy, mostly for AC

The extremely air-conditioned computer farms known as data centers are the gas-guzzling jalopies of the technology world. Some require 40 or 50 times more power than comparably sized office space.

So with energy costs high and environmental friendliness making for good public relations, more tech companies are touting ways they are “greening” data centers, which serve up Web pages, swap Internet traffic, and process and store business information.
But it’s a lot easier to put out a news release than to build a data center with a significantly smaller environmental footprint. Even as efficiency improvements are reducing the energy gulped by many kinds of hardware, the industry’s overall electricity consumption could double from 2006 to 2011 as demand grows.

A new report from the Environmental Protection Agency estimates that the easiest, least-expensive changes to data center operations — involving tweaks to software, layout and air conditioning — could boost efficiency by 20 percent.

But even that level of improvement would still lead to higher overall electric use in the coming years. Going further, and actually reducing information technology’s strain on the electric grid, will require a more aggressive commitment. The EPA says a 45 percent improvement — enough to lower electricity use by 2011 — can be achieved with existing technologies.

Depending on the configuration and the equipment involved, as little as 30 to 40 percent of the juice flowing into a data center is used to run computers. Most of the rest goes to keeping the hardware cool, since heat saps performance.

Unlike in other office space, that AC cranks year-round, to overcome the 100-degree-plus air that the computers throw off.

Almost all the energy that goes into the air conditioning systems is used to run giant chillers that make the air pumped through the rooms’ raised floors a brisk 55 degrees or so, sometimes as low as the 40s. Such extremely cold air is blasted in to guarantee that no single server’s temperature gets much above the optimum level, which is around 70 degrees.

The main reason for the AC overreliance is that data centers were built for one thing — to maximize the performance of the Web sites, computer programs and networking equipment that they run. If the air conditioning is colder than necessary, so be it.

Seattle PI