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POWER SUPPLY Power Supply

The route to standardization is exemplified by the Open Compute Project’s (OCP’s) Open Rack
initiative, which rolled out ORv3 in 2019. In response to demands for increasing power density
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at both the component and system level, the latest 21-inch–width open-rack design supports

48-V power delivery schemes, which provides significant advantages compared with prevalent 12-V
architectures. These advantages include improved power-conversion efficiency that leads to ~1.1%
power bill reduction (as estimated by the U.S. Energy Information Administration), improved thermal
performance, and ~1.5% lower hardware costs. The efficiency benefits of 48-V architectures will be
discussed in greater length later in this article.

Part of the hardware cost reduction is the current industry shift from classic power supply modules
to power shelf architectures. The rack-mountable configuration of a power shelf is space-efficient,
taking 1U of a 44U rack for the supply and 1U for battery backup unit and thus allowing each rack to

accommodate up to 42 compute blades. Importantly, the integration of lithium-ion battery backup
units with other components on the rack confers major advantages in terms of granularity and
the elimination of long cable runs to separate rooms housing lead-acid battery banks. The same
advantages translate to organizations using 19-inch open-frame racks, which have compute density
(and thus power requirements) that parallel those of organizations using OCP designs.

THE DRIVE TO SAVE ENERGY

Standardization, In the U.S., data center power consumption is expected to continue growing at a rate of 4% to
5% annually until 2022 and beyond. This is far below the rate of growth in data center compute
capacity and is a testimonial to the effectiveness of industry efforts to reduce power footprints
Energy Savings Drive while improving the efficiency of power supplies. While improvements in efficiency since 2010 have

had a dramatic impact on power usage (Figure 1), the need for continued innovation is clear.
48-V Power in the Data

Center

By Harry Soin, senior director of technical marketing for the Hyperscale
segment at Advanced Energy

With capital investments ranging from hundreds of millions to billions of dollars, it’s no surprise
the owners of state-of-the art data centers are doing everything possible to drive down costs. And

with the energy to operate data centers representing 3% or more of worldwide power consumption,
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maximizing efficiency is a priority. Combined, these two factors drive two trends: a move toward
standards in design of data center equipment and a matching push for high efficiency. When
looking at powering the compute equipment, these trends converge to drive the evolution of 48-V
power supplies. Figure 1: Data center energy consumption (Source: U.S. Department of Energy)

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