Thinking micro about PUE

You've doubtless heard of the power usage effectiveness (PUE) metric touted by the Green Grid, the U.S. Environmental Protection Agency, and others interested in the greening of data centers. That's the ratio that figures out how much facilities and cooling infrastructure is needed for corresponding technology infrastructure. Well, now one company is trying to take that concept to a more granular level with a new concept that it is touting as "Micro PUE."

This idea, proposed by vendor Trendpoint Systems, postulates that PUE should be applied for each individual cooling unit, rather than just as an aggregate number. The calculation measures that energy used by the cooling unit along with the heat removed by each unit. It's the same formula as PUE but focused down on the cooling unit level. "PUE is a nice metric, but it is a single number. It is difficult to get information from a true management level. Our whole focus is to get down to the granular level," says Trendpoint CEO Bob Hunter.

Sometimes a focus on reducing IT loads could actually raise an overall PUE number, Trendpoint notes. For some of the biggest potential impact, the focus should be on reducing cooling energy at a more detailed level, according to Hunter. Trendpoint outlines its ideas and some examples in a paper called "Micro PUE: The Key to Data Center Energy Savings."

Mind you, Trendpoint's theory is not self-interested. The San Ramon, Calif.-based company makes and sells energy management systems for data centers under the EnerSure line, which is essentially a smart meter for branch circuits. It provides the "ecometer" technology, if you will, that is used within technologies sold by CA and Schneider Electric (to name just two). Its customers include Facebook, the Federal Aviation Administration and VMware.