THE VAST computer data centres needed to make the internet work have become a major problem in energy terms. They burn up about 2 per cent of global electricity production – and 50 per cent of this energy is required to cool down the computer hardware.

This gives data centres a particularly unattractive carbon footprint and better, cheaper ways must be found to get rid of this excess heat, says Dr Gerhard Ingmar Meijer of IBM Research in Zurich.

He believes it is time to introduce water-based cooling systems for these warehouses full of computers and move away from the chilled air methods. It would save considerable energy and hence money, reduce the industry’s carbon footprint and also open up the possibility of using the resultant thermal energy in district heating, Dr Meijer writes this morning in the journal Science.

“The energy consumption challenges posed by such data centres are considerable,” he says. Internet-driven electricity demand reached 330 billion kilowatt hours of power in 2009, he says, at a cost of about $30 billion (€22.1 billion).

The ecological consequences are enormous, with this electricity production resulting in 200 million metric tonnes of carbon dioxide, about 0.7 per cent of global energy-related emissions of this greenhouse gas.

Electricity will always be needed to make our computers go, but improving the cooling systems would deliver immediate savings, he believes. “The key culprits are the server microprocessors, or more precisely, the transistors inside these microprocessors.”

These can get as toasty as the hot plate on a cooker, and the problem only gets worse as we pack more and more transistors into smaller and smaller chips.

His suggestion is to convert to warm water cooling systems, which could run at up to 60 or 70 degrees but still keep the chips from overheating. There is much greater efficiency available by using water flowing through microchannels built into the chips compared to forcing chilled air over cooling vanes. Water cooling for computers was last used in the 1980s on the big systems including the Cray-2 supercomputer. Chilled liquid cooling was brought back into play recently in high-end mainframes and densely packed servers, he adds. His hot water cooling system “has compelling advantages”. First, chillers are no longer required year round, which would see an immediate 50 per cent fall in energy consumption.

“Second, and perhaps most important, direct utilisation of the collected thermal energy becomes feasible, either using synergies with district heating or specific industrial applications,” he writes. By making use of this waste heat “the green diligence of data centres would be upped substantially”.