Active Power's green UPS is truly cool, say users and analysts.

The CoolAir DC, which was introduced recently, uses flywheel technology as an alternative to lead-acid batteries used in most UPSes. In flywheel technology, a magnetized wheel rotates. When power is disrupted, the momentum of the flywheel generates energy, which can be converted to electricity that will be used to power the data center until the backup power generator kicks in.

"Lead-acid UPSes consume a lot of space in data centers and are sensitive to conditions prevailing in data centers such as dust and temperature," says Farah Saeed, industry analyst for Frost & Sullivan.

"They also generate a lot of heat, which causes degeneration of the UPS itself. Flywheels on the other hand, can handle voltage sags and surges better [in] situations that could slowly drain the batteries of a traditional UPS."

Active Power has installed several of its systems at Freescale Semiconductor in Austin, Texas.

"We have found Active Power to be an effective and environmentally friendly backup power solution," says Glaston Ford, a spokesman for Freescale Semiconductor in Austin, Texas. FreeScale uses the Active Power systems - including a CoolAir DC unit - to protect its wafer processing equipment.

"Active Power has played a successful role in helping us manage through power disturbances this past year which were caused by bad weather or power transients," says Ford. "It has helped us avoid lost production time and lost product, thereby resulting in cost avoidance."

According to Frost & Sullivan, the flywheel UPS market only represents a small portion of the total market for UPSes. The total worldwide UPS market is estimated to reach $6.17 billion in 2006, indicating a growth rate of 7.1% over 2005. The flywheel UPS market, which consists of both static and rotary UPS systems is estimated to reach close to $200 million in 2006.

Active Power was founded in 1992 by Joseph Pinkerton, formerly with FRC, a research and development company. The company is listed on the Nasdaq and raised $138 million by going public in 2001.

CoolAir DC is available now.