Today's data centers pack more processing power into smaller physical spaces than ever before. But too much of a good thing creates new challenges for next-generation data center design.

Consolidation has decreased the physical footprint but has created new power and cooling challenges. Ten years ago, data centers used 30 to 50 watts of power per square foot. Today's data centers gobble 150 to 225 watts per square foot, according to research firm DatacenterDynamics in San Francisco. "That number is going up steadily," says Joshua Aaron, president of Business Technology Partners Inc., a New York-based consultancy. "Blade servers and virtualization allow you to pack all this into a data center, and it requires more power for that equipment."

What's more, because data centers hog power and cooling resources, there's a big push to design them in a more energy-conscious way -- with recycled materials, raised floors for maximum cooling efficiency, and alternative natural power sources.

Add to the mix a need for complete redundancy in uninterruptible power supplies, and data center designers face a delicate, ongoing balancing act.

"I think the ultimate goal is to develop and operate a data center where you maximize the utilization of power within a given space for the lowest life-cycle cost without sacrificing reliability," says Jeff Monroe, executive vice president of strategy and business development at DuPont Fabros Technology Inc., a data center provider in Washington.

When building your next data center, your best bet is to be flexible and keep an eye on your company's future needs. Here are some goals to keep in mind.

Plan for Maximum Efficiency

Equipment must be configured in a way that is efficient to operate and maintain, Monroe says. "Space plans must allow for the efficient deployment of servers such that the end user can consume as much of the available power as possible while still optimizing heat transfer and rejection," he says.

Raised floors and efficient cooling and heat flow are helping with power efficiency.

Managed hosting provider Rackspace Hosting builds its new data centers with raised floors so cool air under the floor can be pulled up through the room and hot air can exit from the ceiling. Overhead air conditioning ducts require larger fans and water pumps and, consequently, use more energy. "In one of our data centers, we forecast as much as a 10% to 15% efficiency improvement by moving to an under-floor model," says Troy Toman, vice president of operations at San Antonio-based Rackspace.

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