Efficiency in a data center is a goal for every operator.
The most efficient use of a “kW” of power in a server matched with a “kW” of cooling is ultimately the goal. The focus on “PUE” or Power Usage Effectiveness has been around the last 15 years. It is the calculation of input power used in the facility vs. units used to produce/cool/transfer the power. Therefore, you can create a higher data center PUE by inefficiencies in distribution transformers within the facility, poor airflow and cooling methods, inefficient UPS and Battery Systems losing internal kW power, and general choices of technology during construction.
A lower data center efficiency PUE is considered in the low 1.2-1.4 range. Meaning if kW used is 1, then you are using 20-40% to support that kW by cooling, distribution, etc. Many traditional older centers would have a PUE of 2.0. As it was acceptable to use a 1:1 ratio of cooling to power used. With today’s technology, and proper design can achieve PUE in the 1.2-1.5 range.
Geographical location can have an effect on PUE and make it change throughout the year. Northern climates which can achieve many free cooling hours per year lower PUE in cold months, and spike in warmer months. California climate can achieve a more constant PUE as the temperature and humidity stay relatively constant. Different cooling technology can be used to take advantage of those locations.
It is possible to target a PUE during design phase of a data center. Understanding that the PUE is a direct relationship to operational costs later. A higher PUE will cost more on an annual basis to operate than a lower PUE.
Investment into a highly efficient mechanical systems up front can save large amounts of operational dollars during later. Choosing technologies such as cooling systems, UPS Systems, space layouts, containment, and distribution can all affect PUE.
PUE can and is an arbitrary number when comparing site to site. Not all data center facilities run at full capacity. Many new sites will have less than half the utilization of load centers. Therefore, PUE may be higher to start, and even out to nominal as loads increase to capacity. You may install 1 megawatt of UPS power into a facility and use 200kW day one. You may have sized your mechanicals and facility around the 1 MW. Therefore, you are going to have some inefficiencies during ramp-up. Many of today’s VFD’s in mechanical systems can accommodate for this and provide a very efficient PUE day 1 even at these low load levels.
Our FGCC professionals are experienced at reviewing current technologies that will work for your facility requirements and your PUE goals. Contact us to go over a plan with you.