Capgemini opened the doors on a new data centre near London on Tuesday that it sees as a showcase for green design. The center, called Merlin, will be one of the most energy efficient in the industry, but "similar in cost to a traditional data centre," said Capgemini's CEO of Global Infrastructure Management, Richard Dicketts.
As if that wasn't enough, the company has also paid attention to the sourcing and eventual recycling of the materials used, and the problem of urban sprawl.
Merlin will have a power usage effectiveness (PUE) of around 1.1, according to Capgemini. PUE is the ratio of the overall power consumption of a data centre, including lighting and cooling, to the power used by the IT equipment: with a PUE of 1.0, all the power would go to the IT equipment.
The industry average PUE is somewhere around 2, according to Capgemini, meaning that about half the power is used for cooling and other functions. Many recent data centres do far better than that: In February, Hewlett-Packard opened one in the northeast of England that uses cool sea breezes to achieve a claimed PUE of 1.16, and in September Yahoo opened one near Niagara Falls that it said had a PUE of 1.08.
Both HP's and Yahoo's data centres rely on cunningly designed buildings on special sites to optimise cooling, but Capgemini's is in a former paper warehouse in Swindon, far from the sea or spectacular waterfalls. "We wanted to use an existing building," said Dicketts.
To achieve its low PUE, Capgemini uses 250-square-meter prefabricated modules from a company more used to building field hospitals and ventilation systems for the chemical industry. Their hot-aisle, cold-aisle construction allowed the modules to achieve a PUE of 1.08 in factory tests, but there will be additional power losses on site, raising the effective PUE to around 1.1, the company said.
The modules arrive in three truck-sized pieces and are assembled on site. They could be installed inside any building large enough for the crane to enter, said Dicketts or they could just be set on concrete bases outdoors. The building is not necessary for their protection, he said, although it adds to security and to the comfort of staff moving between the different modules. This makes Capgemini's approach suitable for many brownfield sites, almost anywhere with the necessary power and telecommunications infrastructure, he said.
Merlin contains four modules to date, with room for 12 more. In principle, Capgemini could go further: "We could double-deck the modules: It's feasible, technically," said Dicketts, adding that it might make more sense to build a second site nearby, for redundancy or disaster recovery, rather than expand the existing one.
Only two of Merlin's modules are full so far, one occupied by one client and the other shared by three. When the time comes to expand, Capgemini will add new modules four at a time, to simplify the construction of the necessary power systems.
The site has backup generators, and its uninterruptible power supplies rely on flywheel generators rather than lead-acid batteries, a move intended to reduce the potential environmental impact of the site.