Data center designers share secrets for going green

Rising utility costs from running denser and hotter server and storage gear are forcing IT managers to redesign data centers to be more energy efficient.

Take the case of Dan Wilson, IT operations manager at Osram Sylvania in Danvers, Mass. Getting an updated electrical bill prompted his data center redesign. "We were being charged a prorated amount that had been determined several years before that no one had ever updated internally when energy costs rose," Wilson says. "When accounting did upgrade it, we said 'Oh wait, they are hitting us with a real bill now.' The [amount] came as a shock to us."

Wilson manages two data centers for the lighting manufacturer -- one in Danvers and the other located above a loading dock in a facility in Manchester, N.H. When trucks enter or leave the loading dock, much of the benefit of the air conditioning in the data center is lost as the overhead doors open and close. Wilson's 2,000-sq.-ft. data center also suffers from the sun beating down on an exposed wall of the data center and on the roof.

Also, when Osram Sylvania designed its data center, it put racks of servers parallel to the air-conditioning units, thus cutting their effectiveness. "We set up the data center so it looked good," he says.

In an effort to make its data centers more energy-efficient, Osram Sylvania hired Degree Controls Inc. to conduct a thermal study, which pinpointed hot spots where excess energy consumption occurred. Wilson installed sensor-based and fan-assisted AdaptivCool floor tiles that monitor the data center for hot spots and then dynamically manage the flow of cooling to racks and exhausts hot air back to the computer room air conditioner (CRAC) intake.

"We have four sensors spread down the row of servers," he says. "When those sensors determine that we've hit a certain temperature collectively, it will kick in the fan to push more cold air up at the far end of the row."

Wilson is also reorganizing his primary data center, eliminating half of the nine racks of servers by virtualizing IBM AIX systems. He plans to realign the remaining servers into hot and cold aisles.

The costs of getting it cool

The proper and efficient cooling of data centers has gotten a lot of attention lately from data center designers and other IT professionals. Research firm Gartner Inc. predicts that by the end of 2008, nearly half of the data centers worldwide will not have sufficient power and cooling to support new high-density server and storage gear. Gartner estimated that in 2005 alone companies spent $6 billion powering data centers in the U.S. By 2011, more than a third of data center budgets will be allocated to environmental costs, the market watcher estimates.

Data centers are going green in large part because of rapidly escalating energy costs, but also to be a good "corporate citizens." At 365 Main Inc., a data center builder in San Francisco, designers have taken building green to heart.

In Newark, Calif., 365 Main has built from the ground up the first LEED (Leadership in Energy and Environmental Design) certified data center in the U.S. The facility, which tops out at over 136,000 square feet of floor space, features the use of recycled and locally obtained building materials, computer room air handlers and CRACs that consume 30% less energy than traditional CRAC units, makeup air handlers that use outside ambient air, and energy-efficient lighting and water-efficient landscaping. (For more information about LEED certification, read this story.)

"The air handler units feature variable-state motors that by ramping up and down use 30% to 60% less energy and still keep the facility cool," says Miles Kelly, vice president of corporate strategy.

Kelly is also using a free source of energy -- the ambient outside air -- to cool the Newark data center.

"We are also using a cooling technology that, when the outside temperature is less than or equal to 60 degrees, we will be using outside air to cool the facility," says Kelly. "In the Newark data center, for example, we expect to be able to use ambient air at least a third of the year if you consider these facilities are running 24 hours a day, seven days a week. The result is we will be able to reduce our yearly operating cost by $500,000."

Despite such cost savings, there is a premium to building energy-efficient data centers.

"It's not a zero-cost leap to go [green]," says Kelly. "We expect to add 10% to the build-out cost. So for a $100 million facility, that's a $10 million increase in construction costs. That's a 20-year payback if you were simply to look at the $500,000 savings per year."

But there are bigger issues at play than just the cost of being green. In Kelly's data center, he was able to lighten the overall footprint of the facility by using recycled or locally sourced materials.

"You get points with the U.S. Green Building Council and the LEED certification to feature a higher percentage of recycled materials," says Kelly.

And utilities such as Southern California Edison and Pacific Gas and Electric (PG&E) are offering incentives and programs for those building green data centers.

"We want to participate in these programs but not diminish our services to our clients," says Jean Paul Balajadia, vice president of operations and founder of 365 Main. "Some [programs] are set up to say 'If we give you 24-hour notice, we need you to turn off your power' -- that's just not acceptable in a data center environment. There are other programs open to us, though, such as the Critical Peak Pricing Program, which saved us $70,000 over the six summer months last year."

With PG&E's Peak Pricing Program, customers are notified a day before a critical power peak event occurs. Usage during summer peak hours is discounted on days when no events are called.

Evil power supplies

For Jeff Biggs, senior vice president of operations and engineering for data center operator Peak 10 Inc. in Raleigh, N.C., there are other factors to be considered in making his data centers green.

"The power supply on the server is the first evil; it's inefficient to begin with," says Biggs. "Its highest efficiency rating is probably 75%. That means that 25% of the electricity you are drinking gets belched to heat immediately and no processing has taken place yet."

Google Inc., which maintains some of the largest data centers in the world, is proposing a shift from multivoltage power supplies to single 12-volt supplies. The company says that if the new power supplies were to be deployed in 100 million desktop computers it would be possible to save 40 billion kilowatt-hours over three years, or more than $5 billion at California's energy rates.

"The other evil is that people always request [uninterruptible power supply] power," says Biggs. "The typical rating on a UPS is 88% efficient. When you combine the power supply and the UPS, it looks pretty disastrous."

The only salvation Biggs says is to keep UPSes heavily loaded because that's when they are most efficient.

At Peak 10, redundant power systems automatically transfer electrical load of the data center to a diesel generator and UPS in the event of a commercial power failure. Each generator can support the facility for a minimum of 48 hours.

"The only other place you can really glean the green seal is how you cool the data center," says Biggs. Like 365 Main, Peak 10 uses dry cooler systems in its data centers.

"The dry cooler system's or glycol loop's efficiencies vary by climate," says Biggs. "If you are in South Florida, it's not very efficient because the ambient temperature is so hot. But if you are in a northern climate, let's say Nashville or Chicago, it is extremely efficient because you can leverage the ambient temperature, which is typically much cooler."

Anytime the temperature is below 40 degrees, Peak 10 uses what it calls economy cooling.

"That means that the outside temperature is cool enough that we can leverage it to cool the glycol down and use it to cool the data center," says Biggs.

For more information:

Seven steps to a green data center

Here's how to save on energy costs and the planet at the same time.

Greening up is about more than just energy

Data center managers talk about the coveted LEED green-building certification, how they earned it and why it matters to their business.

Power pinch in the data center

Rising power and cooling costs are catching some data center managers by surprise. Here's why.

Green computing picks up momentum

Columnist Bert Latamore explores environmentally unfriendly computing practices and possible actions that companies can take now to address the problem.

This story, "Data center designers share secrets for going green" was originally published by Network World.

Copyright © 2007 IDG Communications, Inc.

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