In search of the perfect UPS
Data center managers long for the trifecta of perfect data center power: 100% available, noise-free, no UPS losses - and they're getting closer.
Perfect power is the dream of every data center manager: Always on, no noise or other issues that could cause server problems, and no efficiency-robbing losses. UPS’ can largely provide the first two, but at the expense of the third. Recent technology advancements, though, are moving the UPS closer to realizing all three traits. These advancements are driven by financial as well as environmental pressures.
UPS systems are much more efficient than they once were. A decade ago, efficiency was in the high 80% range. Those losses were a pretty costly toll to pay, but data center managers accepted them in return for reliable power. Most centers had an easy option to achieve losses in the neighborhood of 1%, but that option – Economy Mode (ECO) – created new risks.
The Seldom-used ECO Mode
In ECO mode, incoming power passes directly through the UPS. The servers run off utility power but are still protected in the event of an outage. While accountants love ECO mode, data center managers don’t because of the increased risk. ECO mode passes through noise and other power issues that could create big server problems. When not in ECO mode, most if not all power problems are filtered, providing the servers with Grade A, clean, consistent energy.
Considering the higher efficiency of today’s systems, ECO mode is even less attractive. Transformer-less designs based on fast-switching, low-loss IGBT’s have pushed the efficiency for a current-generation UPS close to 97%, even at low or partial loads.
Efficiency versus Scalability
Manufacturers continue to look for ways to eke out every last amp from their UPS technology, aiming to deliver 100% efficiency with filtered power. Having reached the practical limit for eliminating UPS losses, they are searching for new cost-saving opportunities. One is improved power scalability.
Data centers have traditionally been commissioned with a fully built-out power system, able to support its projected maximum load. However, that load usually isn’t reached for years. In the interim, the center operates with a wasteful, oversized power infrastructure.
UPS manufactures have responded with scalable, modular systems that enable rightsizing to the current load. Most of those systems are based on a legacy, centralized design that includes several single points of failure. The tradeoff of more scalability at the cost of lower reliability makes many center managers uncomfortable.
ABB recently launched a UPS that combines a high-efficiency topology – approaching 97%, comparable to other modern UPS systems – with a pay-as-you-grow, decentralized design that offers both high efficiency and scalability.
Dreaming of Perfect Power
The dream of perfect data center power – scalable systems that are always available, noise-free, and 100% efficient – is likely to remain a dream. But manufacturers, including ABB, continue to relentlessly pursue this ideal that will help data center managers sleep better at night.