Evaluation of 400V DC distribution in telco and data centers to improve energy efficiency

In a typical data center, less than half the energy consumed is delivered to the compute load, with the rest lost in power conversion, distribution and cooling. Traditionally power distribution is at 400/480 V AC in data centers and at -48 V DC in telco facilities. Higher voltage DC has been proposed as an energy efficient distribution option for both types of facilities, and this paper presents an analytical evaluation of several data center power delivery architectures over a range of loads, showing that a 400 V facility-level DC distribution option is the most efficient. The equipment required to support such an architecture is discussed and results from a small scale demonstration are included.