Pros and cons of UPS 'eco-mode' operation for data centers

A recent technical white paper from APC-Schneider Electric notes how "many newer UPS systems have an energy-saving operating mode known as 'eco-mode' or by some other descriptor. Nevertheless, surveys show that few data centers actually use this mode, because of the known or anticipated side-effects. Unfortunately, the marketing materials for these operating modes do not adequately explain the cost/benefit tradeoffs," adds the brief's executive summary.

"The use of eco-mode entails risks," writes Schneider Electric's Neil Rasmussen, the paper's author. "Eco-mode introduces a number of new modes of operation of the data center, and reduces power protection. Current IT equipment is much more resilient to power variations than the IT equipment of prior generations, suggesting that this equipment should operate reliably using eco-mode. However, complex data center systems comprised of a mix of IT equipment, transformers, transfer switches, and other possible non-IT loads are less predictable in their response to infrequent and unusual power events, and their compatibility with eco-mode is less certain. These considerations have greatly limited the use of eco-mode in real data centers in the past, and are likely to continue to do so."

The white paper goes on to demonstrate that, generally speaking, a UPS system's eco-mode operation provides a reduction of approximately 2% in data center energy consumption, and explains the various limitations and concerns that arise from eco-mode use. Situations where these operating modes are recommended and contra-indicated are also described.

View/Download the white paper.