The Open Compute Project, previously limited to a few, innovative motherboards in the public domain, is taking on more depth and variety. OCP now encompasses solid-state disks, an operating system for generic switches, and equipment racks of different designs -- including one backed up by a novel 48-volt power supply.
The latter was donated by OCP's newest member, Google, which designed its own racks based on its experience building its search data centers. Most battery backup power supplies are based on 12-volt designs. Facebook, which founded the Open Compute Project (OCP) in 2011, uses battery packs delivering 12 volts to the rack.
By keeping the voltage at 48, Google loses less power as it's delivered to each shelf in the rack, where it is then stepped down to 12 volts and converted to the alternating current that the devices can use. The higher the voltage, the less power lost in transmission and conversion to alternating current.
Google waits until the last step, feeding 48 volts up to the motherboard's entry point, where the conversion is made, instead of doing it at the top or bottom of the rack. Delivering 48 volts to the device level "reduces energy losses by 30%," noted Urs Holzle, Google's noted chief infrastructure architect, during an appearance at the opening general session of the OCP US Summit in San Jose, Calif., on March 9.
The batteries serve as the emergency backup power that keeps everything running for 12 to 15 minutes in the event of a power outage on the grid. That is presumed to be more than enough time to get emergency generators onsite running and cut in to supply replacement power.
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