Researchers at the University of California, San Diego are running several racks of servers using 400 Volt Direct Current (DC) power to analyze how this approach compares with the use of traditional AC power. The project is being conducted in a 20-foot data center container at UCSD, which houses 10 servers whose power supplies have been modified to accept DC power fed to them from a 20kW DC power rectification system made by Emerson, according to DataCenterDynamics.
The rectification system is installed in the rack enclosure and feeds 400 Volts of DC power to the power supplies designed to take 380 Volts. A future version of the project may use a methane gas fuel cell to power the servers.
The debate over the relative merits of AC and DC power dates all the way back to Edison and Tesla. In recent years, the push for increased energy efficiency in data centers has led some industry researchers to take a fresh look at power distribution architectures.
The benefits of DC have been advocated in a study from Lawrence Berkeley National Lab. But many data center professionals remain leery of DC power, and some vendors argue that high-voltage AC configurations would be a better approach than DC power distribution.
Most data centers use power distribution systems in which AC power from the grid is converted into DC power to charge the batteries, and then converted back to AC for the equipment. The loss of power through multiple AC/DC conversions has been cited as an argument for using DC power distribution.