Speaking of ENERGY STAR, the EPA released a framework document for the newly announced Uninterruptable Power Supplies (UPS) specification last week. UPS, like computer power supplies before them, lack industry standard measurement procedures to specify their efficiency. As the market for energy efficient data center equipment grows UPS makers seem to be increasingly marketing the efficiency of their devices, but manufacturers usually specify 100% load – a condition that a UPS will never actually operate in because many UPS are critically underloaded. Also similar to server power supplies, many UPS are operated in redundant configurations where the load is split between two UPS in the case that one fails. This means that a UPS in this configuration could only hit 50% load, max. The efficiency of power conversion equipment tends to fall off below 50% load, so it’s important to measure and specify the efficiency of loads below 50%, because this is where a lot of this equipment is actually running.
To illustrate the point, here’s a chart of power supply efficiency curves from when I was working on the server specification, which I stole from the ENERGY STAR website:
For servers, EPA specified efficiency all the way down to the 10% load condition because available data indicated that that’s where a lot of the redundant power supplies were being operated. My guess is that ENERGY STAR will be doing a similar thing with UPS, and then the industry will have a way to compare the efficiency of different UPS solutions across much of their operating range. This should be a great help to utilities looking to get verifiable savings through offering incentives or rebates for more efficient UPS.
EPA is also continuing the trend of pushing for standardized reporting requirements (through a power and performance data sheet) and for real-time power and temperature reporting over a standard network. This is also similar to the V1.0 server specification and what is being proposed for data center storage equipment. EPA is looking to add similar requirements for all data center equipment so that data centers can be operated more efficiently when the managers have better access to data on what’s actually happening in their data center. The power and performance data sheet will also be helpful for proving the specifications of equipment when applying for rebates and incentives.
Interested stakeholders can download the new documents here, and offer comments by April 2, 2010.
