Old-style mainframe cooling could come back, because it’s easier to harness hot water than hot air, says IBM
Virtually all servers could be water-cooled in a few years’ time, according to an IBM spokesman. Liquid makes it much easier to re-use the heat, he told a London data centre conference, although other delegates were not so sure.
“We’ll see a return to liquid-cooling in most IT solutions,” said Doug Neilson, a consultant in IBM’s systems and technology group, at the IDC Enterprise Data Centre conference in London. The technique, once used in specialised supercomputers and large mainframes, could now have more general use as companies try to become more energy efficient, he said.
“Water-cooling is a better way to recycle the heat energy,” said Neilson. “If you cool by air it is much harder to capture and condense it.” To harness that energy, it must be transferred to liquid, so it is more efficient to use liquid cooling directly, he said.
Water or other coolants?
Liquid doesn’t mix well with electronics, warned Frank Brand, director of operations at Dutch engineer Imtech, who launched a new data centre design at the event:
“Thermodynamically water is very good but it is not good with electronics,” he said. Organisations wanting to use their heat output would do better to heat the water next to the data centre, he said.
However, some IBM systems are already water-cooled – and it isn’t just the top-end mainframes, according to Neilson. “The electronics are air-cooled, but the frame and rack assemblies, and the doors are water-cooled,” he said. “Some Unix servers use liquid to the back of the chip. Ten years out, water-cooling might be universal.”
Although servers are currently being run at higher temperatures, making water-cooling seem less necessary, it is always the case that higher clock rates and more processing power can be gained by operating at lower temperatures, said: “It’s physics, not IT.”
Neilson also predicted users would move to generating their own electricity to save costs and reduce the losses in energy transmission – a technique advocated by BT and others, although the government’s carbon credit scheme appears to have made BT’s wind farm uneconomic, and is calling other green energy moves into question.