By Jim Stark, P.E., Principal of Engineering, Electronic Environments Corporation
Quickly becoming one of the most viable options when powering a data center, modern advancements in the Direct Current (DC) power distribution model are poised to increase energy efficiency and reliability like never before.
Traditionally, data center power distribution models follow a consistent formula, including multiple voltage power conversions between the electric utility and the server. Distribution transformers, Uninterruptible Power Supply (UPS) systems, and Power Distribution Units (PDU) all introduce AC (alternating current) to DC conversions and voltage transformations in the power chain, oftentimes resulting in wasted energy. This typical power distribution model can include a:
- Conversion from 480VAC to 480VDC within the UPS system
- Conversion from 480VDC back to 480VAC within the UPS system
- Transformation from 480VAC to 208VAC at the PDU
- Conversion from 208VAC to DC voltages within the server power supply
In order to eliminate many of these unnecessary power conversions, energy can be distributed at a DC voltage directly to the server power supplies as opposed to converting the DC power in the UPS back to AC power and then converting back again to DC at the server. Depending upon the age and technology of power equipment utilized, the conversion to a DC power distribution model can result in efficiency gains of 10 to 20 percent thanks to a reduction in the number of power conversions. Though the existence of DC power distribution in the data center industry is nothing new, modern technological developments have made this system more attainable than it was previously. In fact, many telecommunications companies have taken advantage of the efficiency and reliability of DC power systems for decades. Some of the benefits of DC power distribution over AC power distribution include:
- Fewer power conversions between AC and DC voltages result in a smaller parts count, which improves reliability and reduces maintenance costs;
- Fewer power conversions increases system efficiency and reduces energy costs;
- Less equipment may reduce capital investment of a comparable, new AC distribution system;
- Less equipment also reduces the footprint required on site; and
- Harmonic distortion and phase balancing are not a concern with DC power distribution, which eliminates the need for power filtering and minimizes stranded capacity.
Though many telecommunication companies have traditionally relied on low voltage DC systems (48VDC), the higher power consumption requirements of data centers fit better with 380VDC systems. Since data center servers run with higher power densities, this results in an extremely high current draw at 48VDC and requires much larger conductor sizes to provide ample power. The use of 380VDC eliminates this need, while working well within typical server power supply limits. Since they operate in the same voltage range, users of 380VDC can additionally benefit from the ability to integrate with renewable energy sources such as photovoltaic (solar) arrays and fuel cells.
Two major issues which have delayed the acceptance of 380VDC systems in the past include: the availability of DC power systems and server power supplies, and safety concerns related to high voltage at the rack and server levels. Thanks to recent innovations and advancements, DC power systems are now more readily available, prompted by the successful deployment of DC distribution in Asia and Europe and due to groups like EMerge Alliance, which have developed standards for the commercial adoption of DC power. Noting the potential of this shift in data center power distribution, several manufacturers are now producing DC circuit protection and power supply cord connectors which address concerns with user safety related to DC voltage and arc protection.
The data center ecosystem is experiencing an exciting shift in traditional practices, making room for the development of a more sustainable environment as 380VDC and other energy efficient practices become widely adopted.
Join us on December 9 at DatacenterDynamics Converged Dallas to explore this topic further when we present, “Is it Finally Time for 380VDC Power in the Data Center?” at 12:20 PM local time.
To meet with Mr. Stark during the event, please email firstname.lastname@example.org.
To learn more about Electronic Environments Corporation (EEC), visit www.eecnet.com.