Powering servers and IT systems is often the hardest part about operating a data center. Intelligence is the key to better data center PDU, UPS and SMPS designs.
Every server and device uses a DC-to-AC rectifier with switched-mode power supply (SMPS) to modulate output, and the technology has really progressed. Early SMPS designs achieved 60% to 70% efficiency, wasting energy and creating heat. Modern SMPS products hit 95% efficiency by using more effective switching frequencies and superior rectification, and because data center managers size the power supply appropriately to the server, storage array or other load.
Early rack power distribution units (PDUs) were little more than multi-outlet power strips. Today's PDU designs use sensors to monitor power use -- often per outlet -- along with network tie-in so that the PDU can report energy use to a centralized monitoring system, such as a data center infrastructure management (DCIM) server. Similarly, the DCIM platform can control each outlet. Future data center PDUs will add intelligence that refines reporting and energy utilization monitoring.
Backup uninterruptable power supply (UPS) systems haven't changed conceptually in decades, converting utility AC to DC for batteries, which convert DC back to AC for the IT equipment. Constant improvements in monitoring and battery technology add reliability and improve efficiency.
The future of data center power heads in many possible directions. Utility power costs, reliability and environmental concerns make alternative energy sources, such as solid oxide fuel cell generators powered by natural gas or biofuels, appealing. Some organizations are flipping the power equation, making utility power the backup and renewables the main power source. Higher utility voltages in new data centers, such as 208 VAC or 240 VAC rather than 120 VAC, will cut down on conversions. Facebook's Open Compute Project is developing standards for a DC power distribution scheme to run data center equipment, eliminating power supplies at each server.