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UPS Systems, DC Power Can Solve Energy Issues
May 25, 2012 - Contact FacilitiesNet Editorial Staff »
This is Casey Laughman, managing editor of Building Operating Management magazine. Today's tip is that energy-saving UPS systems and DC power can help solve energy issues in data centers.
New UPS systems and high-voltage power supply are the two major trends in infrastructure design and engineering to reduce power consumption. DC power is a rare solution in the United States today, but worth considering the potential benefits and risks to save energy.
Manufacturers have modified the designs of new UPS systems with an "energy-saver" operating mode, which increases their power efficiency by approximately 90 percent while operating at any load. Owners have been cautious to adopt this new operating mode until the new systems prove themselves, but more owners are willing to consider it today.
Operating a UPS in energy-saver mode has clear advantages over the conventional operating mode of older UPS systems, whose efficiency falls into the 30 to 40 percent range at low loads. Even as the load increases on an older unit, it never achieves a higher efficiency level than about 80 percent.
High-voltage power supply is an effective way to cut capital costs and power requirements, and it is an idea whose time has finally come. Running at higher voltages not only reduces the capital cost of wiring as the system uses fewer, smaller wires, but at higher voltages, the current is lower, so less energy is lost through the wire. One downside is the fact that high-voltage computer equipment is still a custom order even though it is more available.
Running a data center on DC power saves energy by reducing the energy losses associated with the number of power conversions typically required in a conventional data center. Energy is lost at each conversion, making this approach less efficient than a DC system, which efficiently converts AC to DC once at high voltage and then distributes it to the computer's power supply.