Fujitsu announces CPU adsorption cooling system

Fujitsu has announced a new technology which it claims allows the waste heat of a computer's CPU to actually cool the surrounding server room.

The seemingly impossible achievement, unveiled at the International Conference on Power and Energy Engineering in Shanghai, could spell massive savings for data centre operators: according to Fujitsu's calculations, the system reduces the total air-conditioning power requirements for an average data centre by around 20 per cent.

With electricity costs rising, HVAC - Heating, Ventilation And Cooling - costs are one of the biggest barriers to running a data centre. It's the high cost of cooling that leads to places like Dublin - not known for its heatwaves - becoming hotbeds for data centre activities.

Fujitsu's cooling system could help drop costs, or make warmer climes more suitable for data centre use - and it works in a clever manner. By grabbing waste heat from the CPUs in a server rack, it can spit out chilled water at between 15°C and 18°C.

While that might seem unlikely, Fujitsu's system uses a relatively common cooling technology: an adsorption heat pump. By taking in warm waste water into a special adsorption material and then vaporising it, an adsorption heat pump is able to bleed off heat quickly and return the water far cooler than it originally arrived.

The principle isn't new, but a stumbling block has always stood in the way of its use in data centre cooling: typical adsorption materials require the water to be significantly hotter than that found inside an average watercooling loop.

That's where Fujitsu's breakthrough comes in: a new adsorption material developed by Fujitsu Laboratories offers the same performance at temperatures of around 40°C to 55°C - around that of a watercooling loop. Using this new material along with some old-fashioned engineering, Fujitsu is able to harness the waste heat for cooling purposes.

It's not quite as simple as it sounds: for the adsorption material to work, the temperature of the water can't dip below 40°C. While the server is under load, this shouldn't be a problem - but when the load drops, so does the heat output.

To solve this problem, Fujitsu has developed a flow control system which analyses CPU load and controls just how much water flows into the adsorption heat pump in order to keep the temperature high enough to work continuously.

With Fujitsu increasing its lead in supercomputing circles - thanks largely to the K Computer, officially the world's first ten-petaflop machine - these technologies will help it gain an edge over its rivals, but there is a slight catch: it doesn't expect to have a commercial implementation ready until at least 2014.