Active Power is going green with the introduction of a flywheel energy storage system that replaces lead-acid batteries and cools the data center environment even as it powers it.

Active Power's CoolAir DC, which became generally available last week, is a lead battery-free UPS that produces cool air during system discharge to mitigate heat buildup in data centers. A single CoolAir DC unit can provide 85 kilowatts of power for up to 15 minutes - it is intended for backup power applications in the 10-100kVA range found in small data centers.

CoolAir DC uses flywheel technology, a concept that has been applied to potter's wheels and in planes, where they help control altitude. A flywheel consists of a heavy rotating disk that as its momentum increases, energy is dissipated, which can be stored as electricity. When power is disrupted, the inertia of the flywheel continues to generate electricity, which can be used to power the data center until the backup generator kicks in.

Flywheel UPSes cost about the same as lead-acid battery UPSes, Active Power claims. While a conventional battery must be changed or recharged every three to four years, flywheels have a lifetime of approximately 20 years, during which time the bearings that hold the flywheel in place need to be field-replaced. And with flywheels, users don't have to consider the lead disposal cost and possible contamination of conventional UPSes.

Active Power also makes several other flywheel systems that can be used to replace lead-acid battery UPSes or to complement them by providing constant power during power surges, sags or fluctuations.

The CleanSource DC is a flywheel-powered UPS that can be used stand-alone with a backup generator or in concert with a traditional UPS.

Active Power competes with vendors of UPSes such as Emerson Network Power and American Power Conversion (APC). While most of Emerson's products are conventional lead-based USP systems, the company introduced the Liebert FS, which can support up to 150kVA UPSes. APC does not make flywheel UPSes.

The CoolAir DC starts at $29,000.

Here are links to some more articles about cooling technology and energy efficiency:

HP's server cooling technology is inspired by model airplanes

IT turning green: New regulations make hardware more environmentally friendly

How to cool a data center you could bake a pizza in

Next time: What analysts and users have to say about CoolAir DC.