The July 19, 2007 meeting of the SVLG data center energy efficiency sub committee focused on Direct Current (DC). When asked why data centers aren’t run with Direct Current, the answer was “It has always been done that way”. Possibly time for a chance in the data center environment…
You know from reading this column that I am really pleased to be able to audit and support the Data Center Energy Efficiency project sponsored by Silicon Valley Leadership Group companies. I don’t think I’ve ever been very clear about what their objective is – I’ve always just sent readers to their URL. They are sponsoring a venue and a peer review process for several pilot projects in three categories that impact data center energy utilization, equipment, and data center design & construction (power distribution & conversion, cooling systems, lighting, configuration, and energy sources, etc.)
Case studies will be presented in a public forum in Silicon Valley, hosted by Sun at their Santa Clara campus in February 2008 documenting capital cost, energy savings, payback period, ROI, and CO2 emissions reduction and green house gases saved if implemented across the USA for each demonstration project. Ray Pfeifer, a Silicon Valleyentrepreneur, has volunteered to chair this sub-committee and has put in endless hours of work to create a framework for success.
It is also, by its nature, an educational forum, by vendors with new energy efficient solutions, and leading data center operators sharing their successes. The presentation made just last week was from Bill Tschudi of the Lawrence Berkeley Labs, who has been chairing a program over the last 15 months to investigate Direct Current usage. He outlined considerations for improvements and change in Direct Current (DC) distribution to a data centers because 50% of electricity sent to the data center actually goes to drive appliances, the rest is lost to an inefficient infrastructure system. Today, there are five power distribution considerations to consider, that is whether to add Direct Current to the already present Alternating Current electricity source. These include the availability of electricians, the availability of UL rated equipment, the safety involved in disconnecting DC plugs, and the efficiency of distributing higher (600) voltage to the data center.
Going forward, solar, wind or fuel cell power are optimal DC power providers and one can switch among them automatically as conditions for one or another optimize. Lighting, HVAC and onsite power production can operate on DC as well as AC.
Finally, we discussed why we (users and vendors) have not set a worldwide standard on voltage. A second issue discussed is standardized DC connectors – it seems European Community standards are far ahead of those in the USA. Visually and physically different connectors would overcome the problem of accidental arc-flash and a more cost efficient product category for appliance manufacturers. These conversations have been circling about for four or more years, and will be answered over the next 18 – 24 months. You can read more technical information about Direct Current here.
Have a green day!