2011 UPS/Power management Trends
The modern uninterruptible power supply (UPS) provides datacentres with emergency backup power to keep IT equipment running through short power disruptions, bridges the time needed to start backup generators for longer power disruptions or allows time for controlled shutdown if no generators are available. The UPS has also taken over the role of providing conditioned power and isolating building power from noise and waveform distortion caused by the equipment.
With energy efficiency becoming so important, infrastructure and operations managers are reviewing the energy efficiency of all their equipment. UPS is one of the more important pieces of datacentre equipment that ensures energy efficiency. Older UPS systems used a significant amount of energy that was not in proportion to load. As such, it becomes even more critical to use less energy and to use it in proportion to load – as datacentre management worry about high availability.
Many centers run a 2N or 2N+1 configuration, which have two completely separate power paths that are fully active, each with half the load. This means that each path is running at a maximum load of only 40 per cent (so that it will not exceed the 80 per cent load when handling a path failure) and if the UPS system does not have high efficiency at lower loads, extra power will be wasted.
Energy efficiency is a measure of the power load coming out of the UPS divided by the power load going into the UPS. The energy efficiency of older UPS systems was such that its energy-efficiency curve fell off dramatically at low loads.
For example, a UPS might have an efficiency rating of 98 per cent at a 100 per cent load and a 70 per cent efficiency at a 25 percent load. The high-efficiency UPS does not fall off significantly in efficiency as the load decreases.
UPS vendors and resellers can aid customers by providing a power efficiency curve showing the UPS efficiency over a range of loads and not just at maximum load. Data center management should examine the equipment placed on the UPS load to ensure it is on UPS power from a power-conditioning and availability need perspective.
Using high-energy-efficiency UPS systems can save a significant amount of power, leading to lowercosts and a better carbon footprint.
- Gartner research vice-president, John Phelps