Comments on: Which UPS is Right For the Job?

By: Gary Anderson, Marketing Manager for Applied Systems, Liebert Products and Services, Emerson Network Power

Thu, 15 Oct 2009 18:55:03 +0000

Emerson Network Power’s Energy Logic roadmap (http://tinyurl.com/7dhks3) presents a modeled scenario for enhancing data center energy efficiency and found that the UPS represents just 5 percent of the total power consumed in the data center today. While enhancing UPS efficiency is important, a 2 percent improvement in UPS efficiency could not account for a 50 percent improvement in data center efficiency, even when the cascading effect of energy savings across systems is taken into account. There is also some risk associated with going to different topologies—you may be trading efficiency for availability. Data center managers should really look at the potential impacts of new technologies to ensure that they are improving efficiency without compromising on availability.

By: Ernie

Ernie — Thu, 15 Oct 2009 11:47:29 +0000

I have to agree with Jeff, the UPS efficiency is the smallest part of the equation. Hot and cold isle arrangement and energy efficient cooling for the dense servers that are being utilized. These two elements are the corner stone’s to utility bill reduction.

The first step to efficiency is to have a cooling and power assessment to get a base line reading on the data center. Use the assessment to look for areas of improvement. Implement the changes noted and perform the assessment again. Numerous facilities have installed utility monitoring devices incorporated with the building management system to determine efficiency on a daily basis.

By: Jeff

Jeff — Tue, 13 Oct 2009 14:07:00 +0000

“With best practices and the right choices in equipment, data center managers can reduce energy consumption by nearly 50 percent. That means that almost three-quarters of the power utility bill will fuel actual IT processing, compared to less than 50 percent of the power supplied to a normal data center today.”

The paper makes quite a leap of logic. It discusses only UPS efficiency, and the prime example is switching from an 85% efficient unit to a 96% efficient one, which can be a dramatic savings but it’s nowhere close to an overall 50% gain in support equipment efficiency unless you run a data center that doesn’t spend ANY energy on cooling. For that to happen under more normal circumstances, you would need to switch from a 66% efficient UPS to a 100% efficient UPS. For example: a 1MW utility load with a compute load of 500KW, UPS loss of 250 KW, and AC load 250KW. To go from 50% overall efficiency to 75% overall efficiency you would need to erase ALL the UPS loss, and then you need to spend 250KW more on compute load without your AC load going up at all (i.e. to switch from 500/250/250 to 750/0/250). That seems like a bit of a stretch.