Focus on energy utilisation, not generation

Over recent years the datacentre has emerged as the primary focus for many firms’ attempts to limit both their carbon footprint and their soaring energy costs. This has led some companies to explore the idea of using renewable energy sources such as the sun and wind to power their datacentres.

However, Patrick Fogarty, director at engineering consultancy Norman Disney & Young (ND&Y), insisted a focus on renewable energy could prove misguided for many datacentre managers. He cited a recent feasibility study ND &Y undertook for a new 200,000sq ft, £100m datacentre, which found that with the facility requiring 25MW of power per year renewable energy was largely unfeasible.

The study assessed wind, solar and ground source cooling technologies and found they would generate a fraction of the power required. “The best we could hope for was maybe one per cent [of the required energy] on that site, and to achieve that one per cent we’d probably spend [up to] £3m,” explained Fogarty. “My contention is that we should be [focusing] on sensible engineering to pull down the energy demand in the first place.”

To cut datacentre energy demand Fogarty first advocated avoiding energy-intensive rack or room-cooling systems in favour of “all air” or fresh air cooling systems. “For 75 per cent of the time in our local environment we can operate on an outside air cycle, meaning we’re not using our chillers,” he explained. “Typically, in these facilities our chillers are 30 to 40 per cent of our energy load, so potentially we can [cut overall energy use] by 25 per cent.”

Similar savings can also be achieved by addressing the huge amount of power wasted through inefficient power supply units, Fogarty said. He claimed just 10 per cent of the energy going into a datacentre typically makes it to the processor, with much of the wasted power lost through inefficient server power supply units.

“If you’re out there buying servers, make sure you choose ones with efficient power supply,” he said, adding that this investment would in turn limit cooling costs as less power is wasted as heat.

An efficient power supply combined with more cutting-edge, energy-saving technologies, such as virtualisation software, direct chip cooling and more energy-efficient software design, could slash datacentre power use to five per cent of current levels, Fogarty contended.

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