Part 2: DC Power Offers Unique Benefits To Data Centers
DC Power Offers Unique Benefits To Data Centers
September 2012 - Power & Communication
DC power offers many unique benefits to data center applications, and a new standard for the use of DC power in data centers has been developed and is currently in the process of being adopted by the EMerge governing board.
"Data centers that use 380VDC power distribution to the rack have been shown to operate up to 28 percent more efficiently than existing ones operating on 208VAC, and even at higher AC voltages (415VAC), the advantage still approaches 8 percent," says EMerge Alliance representative Guy AlLee of Intel's energy labs.
Efficiency isn't the only benefit that DC power offers data centers. EMerge Alliance representative BJ Sonnenberg, manager of business development at Emerson Network Power, says that "DC data center power distribution equipment is generally more compact, takes up to 33 percent less floor space, and can be between 200 to 1000 percent more reliable" than its AC counterparts.
A study conducted by Validus (ABB) and GE revealed that DC data centers should have up to a 36 percent lower lifetime cost.
Although there are some who fear that use of higher DC voltages isn't safe, Dennis Symanski, senior program manager at the Electrical Power Research Institute (EPRI), a non-profit industry group with primarily utility company membership, says that's not the case. Symanski, who currently chairs the EMerge Data/Telecom Center Standards Committee, is also one of two U.S. representatives to the International Electrotechnical Council (IEC) Strategic Group 4 on LVDC, which recently reported the IEC's finding that proper use of 380VDC (plus and minus 190V peak) was as safe as lower voltage 250VAC (plus and minus 350V peak) and, in fact, safer than the higher 415VAC (plus and minus 585V peak).
Symanski reports that EPRI identified at least a dozen new data centers built in the last two years that operate on higher voltage DC, a figure that doesn't include the many central telecom offices currently operating on lower voltage DC power. The most powerful DC data center built to-date was recently announced by leading power and automation technology group ABB and Switzerland-based Green, an information and communications technology service provider. The data center is housed in Green's new Zurich-West data center expansion and is based on EMerge's proposed standard 380VDC technology. Up to a 20 percent reduction in power consumption is expected from grid-to-chip and in cooling.
DC power should strike a responsive chord with data center owners. "The data center community is generally a highly motivated group, especially with power consumption demands following closely the explosive double-digit growth in data center usage annually," Patterson says. "However, data center leaders are also a 'show-me' community when it comes to reliability and uptime, so these early adopter sites are getting a lot of attention. At the end of the day, the increased reliability promised by a move to DC will likely be just as motivating as the energy, equipment, and operating cost savings."