May-June 2009

Uninterrupted and Renewable

The concept of pairing UPS with sustainable technologies is getting a closer look.

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By Carol Brzozowski

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Batteries, points out Olsen, are fragile, require certain temperatures, and consume a larger footprint. He says that flywheel technology has been around for a long time, and, in the past 30 years, has started to replace existing lead acid batteries in mission-critical industries such as data centers, hospitals, broadcasting studios, and industrial applications.

Olsen says while the western world’s energy grid is “fairly robust,” it is still subject to fluctuations, sags, brownouts, and spikes. “That’s where the UPS comes into play and cleans it up,” he says. “It’s 480 volts per 60 hertz, which greatly extends the life of whatever equipment you’re feeding in there. The UPS addresses virtually all power problems by sags, blackouts, brownouts—any irregularities in the power—it fixes that.”

While the UPS does consume energy to condition the power coming in and out of the system, it does so at a 98% efficiency rate, says Olsen. In addition to conditioning the power, it reduces the footprint consumed by batteries by as much as 25%, he says. Operating expenses can be reduced by as much as 50%, he adds.

Then there is the replacement issue, Olsen says. “When you’re dealing with a lead acid battery, it has a three-to-five-year cycle—some may have a 10-year cycle,” he explains. “But there is a replacement of it. You have costs, including labor and materials, to deploy the new batteries. Then there are the costs in energy for recycling. You can question where that toxic waste goes.”

There can be a challenge in combining renewables with UPS for those data centers that have been accustomed to building a certain way for many years and trying to make the paradigm shift, Olsen says.

The biggest shift is on the ride-through, he says. “The pushback we get from time to time is that our flywheel provides 15 seconds of ride-through as opposed to battery—as much as 15 minutes, or even more than that,” says Olsen. “The fact of the matter is the generator will start up in five to eight seconds, assume the load, thereby spinning the flywheel back up again, and it’s ready to go.

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“The remaining 14-and-a-half minutes on a battery system is really used based on the assumption that the generator didn’t start the first time,” says Olsen. “That’s highly unlikely, given an extra crank on the manual engine to get it started—it’s never been proven that’s physically possible to do in 15 minutes. It’s a lot longer than that, if the generator doesn’t start.”

With heat density, operations can’t afford to be on battery for very long periods of time because of the heat load in the data center, says Olsen. “With the UPS traditionally not backing up the mechanical load or the cooling load, you want to make sure you get the cooling loads up and running as fast as possible before your service is essentially burned out,” he says. Next Page >

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