AC Vs. DC Power For Data Centers
In a typical data center, the redundant power distribution system provides 480-volt AC power through an uninterruptible power supply (UPS) and then to a transformer, which then steps it down to 208-volt AC at a power distribution unit (PDU) to feed racks of servers. Within the UPS system, the 480 volt AC is converted to DC and charges batteries and then is converted back to 48 volt DC.
Individual power supplies (typically redundant) within each server convert the 120/208-volt single phase AC into a voltage appropriate for the unit’s needs. These individual supplies are often inefficient, generating substantial heat that the room’s air conditioning system must remove at great expense. This heat can also limit the number of servers that can be housed in a data center and can jeopardize data center reliability if not handled properly.
In total, there can be up to six or more power conversion stages between facility power entry and the microprocessor or other data processing circuits. The power losses due to the use of inefficient power conversion devices from both outside and within equipment result in a large loss of useful electrical power, as well as directly increasing the energy required to remove the heat produced. Thus, for every watt of power utilized to process data, about 0.3 to 0.1 watt is required to support power conversion. In addition, about 0.6 to 1 watt will be required to cool the power conversion equipment.
By skipping conversion steps, a DC-powered datacenter saves overall electricity use through eliminating extra power conversions and reducing datacenter cooling needs, increases equipment densities, and helps reduce heat-related failures.
Read more about this topic: Validus DC Systems
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