This air is at the foot of the servers by grids

1 Equipping the cold power drives groups outside of "data centers", cold groups send a refrigerant (usually of the water) to the air conditioners installed in the server rooms. "There are still a few years, these facilities were in full any time: it was like driving a car with the foot to the floor at all times", said Jack Pouchet, Director energy initiatives at Emerson Network Power, a US group that provides, among others, the cold groups. "We have begun a year ago, to install Carel drives on our cold groups to use our needs: we hope 30 savings on these devices", advance Michel Brignano, Director for the France of Equinix (50 centres of data around the world).

2 Enhance and identify false floors AC blowing cold air in the false floor of the computer rooms. This air is at the foot of the servers by grids. To facilitate traffic, the false floor is now at least one metre deep and contains less in cables: fibre optics, for example, now spend in height.

3 Develop cold corridors computer equipment (servers, hard drives...) are arranged in chassis facing. Cold air rising from the false floor. Locking equipment in a delimited corridor, at each end, doors and, in height, by a cap covering the top of the rack to optimize the flow of cold. "This represents an additional installation of 10-15, but it saves 10-15 on air conditioning", provides Mokrane Lamari, Director of customer operations at Equinix France.

4 Increase the height under ceiling cold air passes from the front to the rear of the cabinets where it is dismissed before clear height. It is then drawn in by the rooms to be cooled, and then injected air conditioners in the false floor. More height ceiling, the air has time to cool before being retired.

5 Recycle the released heat the municipalities of Pantin and Bobigny, East of Paris, are interested in a project of recovery of the heat generated by a data center that French society Etix DataCenter wants to build, from next June. "This stable and constant energy source, would allow these two cities to save EUR 15 million per year," says Charles-Antoine Beyney, President of Etix DataCenter.

6 Take advantage of "free cooling" (free cooling) is to use fresh outside air to cool the rooms. "We chose Dublin to install a"data center"as inaugurated in July 2009, as mean temperatures allow to spend even in summer, to any artificial cooling by heat exchange with the atmosphere", ensures safety in Microsoft France and Bernard Ourghanlian, Director technical. It is possible to mix, according to the times, "free cooling" and air conditioning. "In one of our new centres located in the area of New York, we thus reduced by half for the air conditioning energy consumption", argues Dave Pickut, technical director of Equinix.

7 Increase the temperature of the rooms the American association Ashrae (American Society of Heating, Refrigerating and Air-Conditioning Engineers") believes that computer equipment can now withstand a temperature of 27 C (its previous recommendation referring to 25 C). "Most of the centres have always operated with an average temperature of 22.2 C, but many operators to think, to a better operational efficiency, to this temperature 23.9 C," notes, on his side, Jason Schafer, analyst at Tier-1 Research, a studies and American consulting firm specializing in data centers.

8 Put unused standby servers "many servers installed in these centres work only by periods of a few tens of milliseconds, and then stop for hundreds of milliseconds, analysis assistant Thomas Wenisch, Professor of science and engineering computer at the University of Michigan in the United States and responsible for the program of research PowerNap." We want to add a software layer that would put mode "ensures": the electricity savings could reach 50.

9 Use Microsoft containers installed on its site in the area of Chicago, in the United States, containers assembled by SGI and Dell, containing thousands of servers. Inside, everything has been designed to optimize energy efficiency. Result "80 reduction of energy for air conditioning", says Patrice Gommy, marketing director of IMS for southern Europe.

10 Cool the heart of microprocessors

IBM engineers and researchers from the Ecole polytechnique fédérale de Zurich, Switzerland, have already developed a supercomputer, Aquasar, whose chips are directly cooled with water. It must be opened in June. They work with the Ecole polytechnique fédérale of Lausanne, the application of this technology to a new generation of processors: integrated circuits in 3D, which overlap multiple chips.