IBM will license its technology for cooling servers with water instead of air to a Chicago-area company.

Panduit, a global networking and electrical manufacturer, will license IBM's Rear Door Heat eXchanger product, a five-inch deep cooling door to be mounted on the back of a conventional server rack in a data center. Water courses through the door, cooling the processors in the server hardware.

IBM's water-cooled system reduces server heat output in data centers by up to 55 percent, compared to air-cooled technology, said Tom Bradicich, chief technology officer for IBM's BladeCenter and System x server product lines.

The heat exchanger is part of IBM's CoolBlue portfolio of products to manage data centers more cost-effectively, reducing the heat generated by the increased processing power of servers and the increased number of servers crowded into data centers.

Data center operators who use fans for cooling have been slow to embrace water cooling because "it's difficult to do water cooling inexpensively," Bradicich said Wednesday in an interview. But over the last 18 months, the growth of data centers running more and more industry-standard x-86 type servers "has been getting extremely out of hand," he said. The growth drives up demand for electricity to run more powerful computers and to keep the equipment cool. High energy costs have made water-cooled solutions more viable.

Water cooling is getting a closer look from some IT administrators, but they still have some reservations about it, said Michael Bell, a Gartner analyst, in a Wednesday interview.

Water cooling can be initially more expensive to introduce into a data center than air cooling, and IT managers worry about water systems leaking and causing damage, Bell said. Some are sticking their toe in the water-cooling pool cautiously, clustering their highest powered servers into one part of their data centers and introducing water-cooled technology only in that area.

But as data center electricity bills grow, "I think we'll see water usage coming more into play," he said, adding that it now costs data centers as much to cool a server as to power it.

IBM rival Hewlett-Packard introduced a water-based cooling system for its high-density servers in January.

Also in January, blade server maker Egenera introduced a product called CoolFrame that integrates Liebert's X-Treme Density cooling technology into a blade architecture. Liebert is a division of Emerson Electric.