October 08, 2007, 2:58 PM — Listen to the column The UPS Goes Round and Round, or visit our Podcast Center to hear more by James Gaskin.
Green is the goal of data centers today, and few things store and deliver energy more greenly than a flywheel. That's right, start the flywheel spinning, and when you need electricity, the spinning heavy metal flywheel provides it. The spinning flywheel rotating inside specifically positioned magnets turns kinetic energy (rotation) into electrical energy through electromagnetic induction. That's the promise from ActivePower (.com), a company selling flywheel power conditioning and power backup systems to data centers.
A rotating magnetic field inside a stationary magnetic field creates electrical current. Remember wrapping a wire around a nail, then waving it across a magnet back in seventh grade science class? This is the same thing, only much larger and more powerful.
Tiny amounts of electricity keep the flywheel spinning inside a magnetic housing that reduces the effective weight of the flywheel to about a quarter of its real weight. When power drops, the rotational energy turns into electrical energy and keeps the data center equipment running.
The good news? Quick response time, no batteries to maintain, and a much smaller footprint for the amount of backup power.
The bad news? Flywheels only give about 15 seconds of power. Your backup generator better be ready to take over immediately.
Martin Olsen, product manager for ActivePower, said, "It takes far less energy to keep the flywheel turning than it does to trickle charge batteries. We're over 98 percent efficient." See Olsen explaining how his system works in this video here.
Modern generators kick in within a few seconds, so the 15 second backup power from the flywheel UPS will provide a long enough window for the generator to start. But if generators don't start, it's usually because their own batteries are weak or dead. Olsen explained ActivePower has a feature that uses the flywheel electrical energy to start generators, eliminating one more battery in your backup power system. Yes, the backup backs up the backup.
Olsen says ActivePower has installed over 1600 flywheel systems. They cost a bit more at first, but you never have to replace batteries. You also rely on more environmentally friendly technology than heavy batteries filled with toxins. Return on investment, says Olsen, kicks in after about three years.
A flywheel UPS will take less space than batteries. It's green. And it's a great conversation piece for your data center.
