As is well known, for all their benefits, blades introduce major additional heat into your server rack... And although cooling requirements can be addressed in a number of ways, not everyone is keen on the idea of introducing water into a mission-critical data-center :-)
"...Georgia Institute of Technology is using new technology that moves cooling systems closer to the source of the heat to save about $160,000 annually in utility bills. Jeffrey Skolnick, director for the university's Center for the Study of Systems Biology, oversaw the installation of an $8.5 million supercomputer where space and power considerations were crucial. It includes a 1,000-node cluster of servers in 12 racks using IBM's BladeCenter system; IBM's rear-door heat eXchanger, which places chilled water directly behind servers, does the cooling.
IBM's eXchanger, introduced last year, solves several problems in the 1,300-square-foot center. It needed only half the air conditioning expected--80 tons instead of 160 tons--and reduced airflow lowered noise. With four more racks to fill in the coming months, Skolnick is looking at chip-level cooling to cut power costs further. 'At the time, [the heat eXchanger] was the most viable technology,' he says. 'Every time you do an upgrade, the rules change, and you have to look and see what's available.'
The idea of introducing water or other liquids into a data center scares some IT managers because water can damage computer components and cause short circuits. Imagine a burst water pipe or a liquid sprayer gone awry. But there may not be a good alternative, says Leonard Ruff, an associate principal at Callison, a data center design firm. Callison, which has been testing the SprayCool M-Series, thinks direct chip cooling is so effective that a business can double the amount of electricity used to power computers and boost the number of servers in a rack without overheating a data center, resulting in a 285% increase in processing capability. Callison now markets the system to its customers.
More companies will adopt water-cooled technology even though there is "an almost unreasonable" resistance to water among data center managers, predicts Gartner analyst Carl Claunch. He recommends that businesses include infrastructure for water cooling when building new data centers even if there are no immediate plans for implementing such equipment. They'll eventually need to pipe in water because it's so efficient at cooling, he reasons...."