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Computerworld - Water-cooled server racks remain a rare thing in data centers. But IBM's move last week to offer an add-on water-cooling unit for its Intel-based xSeries servers and other systems should increase the technology's visibility as a potential solution to heat problems.
Water cooling already is on the minds of some users. For instance, the topic was briefly discussed last week at a meeting of the Central Indiana chapter of AFCOM, an association for data center managers. "Nobody was buzzing with enthusiasm," said Jamie Man, who heads the chapter.
Man isn't dismissing water cooling, though. "The way technology is moving to blade servers, I can see a benefit to it, but it will be somewhat down the road," said Man, an architecture and operations infrastructure manager at ArvinMeritor Inc. in Troy, Mich.
Shifting Back
IBM long used water cooling in its mainframes but gave up on the technology as it shifted to smaller and less-expensive versions of those systems a decade ago. Now, the increasing density of blade servers is giving water cooling new life.
IBM's eServer Rear Door Heat eXchanger, code-named Cool Blue, is designed to handle the heat produced by large racks of blades and other high-density systems. It can be retrofitted on the company's standard 42U enterprise rack, which houses xSeries servers, and it's also available as part of IBM's Linux-based Cluster 1350 system. 1U is 1.75-in. high.
Heat eXchanger pricing starts at $4,229, plus installation costs. The device uses chilled water from existing air-conditioning systems in data centers. IBM claims that the eXchanger will remove up to 50,000 British thermal units, reduce server heat emissions by about half and lower energy costs by 15%.

IBM's Heat eXchanger circulates chilled water from data center air-conditioning systems.

Kent Howell, manager of computer operations at Ameren Corp.'s AmerenIP subsidiary in Decatur, Ill., said water cooling is a technology "that may clearly have a value in the future, as servers get smaller and hotter and there are more and more of them filling up data centers."
Water cooling isn't in the immediate future for Howell -- his data center has excess air-handling capacity. But "a year from now, it may be a whole different story," he said.
Cool Blue "is something we would look at," said Jim Krause, CIO at Chicago Mercantile Exchange Inc. "The blade-server issue that thing is addressing is obviously a concern."
Krause noted that most data centers weren't designed to handle the high levels of heat generated by racks of small servers (see story).
Charles King, an analystat Pund-IT Research in Hayward, Calif., said that because of the heat generated by newer processors, many IT managers "are suddenly looking at power and heating and air-conditioning requirements that are going off the scale." IBM's offering could help users "buy some time" before they have to rebuild or retrofit their data centers, King added.
Vendors such as Knurr Inc. and American Power Conversion Corp. already offer water-cooled units for servers. But Gordon Haff, an analyst at Illuminata Inc. in Nashua, N.H., said IBM will bring credence to the technology because of its prior experience with mainframes.
Lucas Mearian contributed to this story.

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