Data Center

Taking a Close Look at Crucial But Unsung Devices: Electric Meters

Data center owners and operators naturally want the most out of their investments, from high availability to high efficiency. But accurately measuring and optimizing data center power is dependent on devices that may not be top of mind for everyone: electrical meters.

As energy initiatives and legislation around energy use continue to increase, the need for more in-depth metering to better understand and optimize energy use is also increasing.  Meters enable you to benchmark your data center’s energy use, identify improvement opportunities, and measure results from energy improvement projects.

Metering systems also provide critical data and analytics that help ensure safe, reliable, high quality, and efficient data center power distribution.  Specifically, metering systems (together with building, energy, and data center infrastructure management systems) can provide the following value:

  • Enable PUE reporting
  • Decrease unplanned downtime events
  • Recover quickly from downtime events
  • Improve the effectiveness of maintenance activities
  • Maximize asset utilization
  • Decrease energy operating expense
  • Enable charge-backs of energy use to internal and/or external clients

A new white paper I wrote along with my colleague David Kidd, titled “Types of Electrical Meters in Data Centers,” goes into some detail on each of those benefits.

The paper breaks down meters into four general levels, namely the building, switchboard, circuit-level and end-use point (i.e. the IT load). Depending on what your objective is with respect to measuring and the type of infrastructure in place, you may not need meters at each of the four levels.  For PUE measurement, for example, you may only need a building level meter that measures the total data center consumption along with end-use level meters that track UPS or PDU output, to get a sense for the IT load.

Within those four general categories, there are seven distinct types of meters that the white paper discusses, namely:

  • Power quality meters
  • Power meters
  • Digital relay embedded meters
  • Electronic trip unit embedded meters
  • UPS embedded meters
  • PDU / busway embedded meters
  • Rack PDU embedded meters

Each type is good for specific applications and has pros and cons.  Power quality meters, for example, are highly accurate and are tested to internationally recognized metering standards.  On the other hand, they’re relatively expensive, large in size and churn out data that requires a skilled engineer to interpret.

At the other end of the spectrum are the embedded meters that come with PDUs and UPSs.  These meters come at no additional cost but won’t be as accurate and, may or may not be verified to metering standards.

The exact level and type of meters you need will be driven by your objective and the physical infrastructure you’re dealing with. As we concluded in the white paper, embedded meters in devices such as UPSs, and PDUs are cost effective and should be implemented whenever possible, so long as you can still meet the goals of the metering system.

To learn more, read the free white paper no. 172, “Types of Electrical Meters in Data Centers.”

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