DC for efficiency

Across the globe, data centers already are consuming some 80 million MWh of energy every year, producing nearly two percent of global carbon dioxide emissions. Soon the demands of data centers will approach the total electrical consumption of Argentina or the Netherlands. Each year the world brings 5.75 million new servers online, and carbon emissions from the data centers that house them are anticipated to quadruple by 2020, if no measures are being taken.

These mounting energy expenses and emissions are two reasons that corporations building large data centers are giving new consideration to direct current, which lost out to alternating current more than 100 years ago in a commercial war over power distribution sources. Servers, storage, network devices and other systems within data centers consume DC, and such alternative energy supplies as solar and fuel-cell sources produce DC. It is therefore reasonable to anticipate that powering data centers with DC from the point electricity enters the building all the way to individual servers could reduce energy losses as well as equipment installation and maintenance costs. Less energy usage, in turn, would mean fewer emissions. ABB set out to demonstrate the wisdom of this approach.

West of Zurich, ABB created a one MW demonstration power system operating entirely on DC. The system was designed to operate on 400 V to minimize losses and the amount of copper required. Built for Green Datacenter AG, the operator of the data center for green.ch, a major European provider of Internet services, the center incorporated the back-up power supply system, a central rectifier, power distribution units and switchgear from ABB, eliminating the need for traditional UPS devices as well as for multiple power conversions. The results were:

  • 10 percent improvement in energy efficiency
  • 15 percent lower investment costs for electrical components
  • 25 percent less space required
  • 20 percent savings in installation costs

The Zurich-West demonstration showed that DC can lead to a simpler and more reliable architecture requiring less equipment and lower installation and operational costs.

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