Power Usage Effectiveness (PUE): Improve Your Data Center PUE Through Cooling and Design

How energy efficient is your data center? Do you know your PUE and how it ranks in the industry? Today’s data centers demand more, making it challenging to meet their needs and remain energy efficient. At the same time, data centers are trying to reduce operating costs.

In this post, our engineers will review:

  • What is PUE and How to Calculate Your PUE
  • Industry Standards and How Your PUE Stacks Up
  • How Data Center Design and Cooling Can Improve Your PUE
  • Additional Ways to Improve Your PUE

Where are you now? How do you measure your data center’s energy efficiency? Power Usage Effectiveness (PUE) is one form used to measure the energy efficiency of a data center. The ideal PUE for a data center is one, meaning all power going into the data center is being used to power IT equipment. Data centers calculate their PUE score by dividing the total facility power by the IT equipment power.

Do you know your PUE? If not, take some time to calculate it using the below formula.


Most data centers will see a PUE anywhere between 1-3. A PUE of 1 means your data center is very efficient. On the flip side, a PUE of 3 indicates those are significant areas for improvement/ very inefficient.

How does your PUE measure up?

According to research conducted by Uptime Institute, the average U.S. data center has a PUE of 1.67, which sits between “average” and “efficient.” Keep in mind that although we will be focused on PUE scores in this post, it is only one component to measure a data center’s energy efficiency.

Google shared that “the average PUE for all Google Data Centers is 1.1.” They also mentioned that their best site could have as less than 1.06 score. How can your facility manager reduce your PUE and save money? Data Center Design One way the data center management is evolving to improve their PUE is through design. Many companies are streamlining their processes by deploying aisle containment systems and racks simultaneously rather than individually. Why? The answer is simple: aisle containment systems allow for greater equipment densities and improved airflow. Here are some additional design elements that can help increase a modern data center’s energy efficiency and improve your data center’s PUE:

  • Power distribution – there are several ways to distribute power in data centers, but properly distributed power increases efficiency.
  • Types of hardware – designers and manufacturers should work together with data center operators to see what kind of configurations are being used. One example of this is using variable-speed fan drives, which fluctuate as needed with the server load.
  • Power and networking – these both drive where data centers are being geographically placed, and some are being built on rivers, using hydropower to reduce energy costs.

Besides design, another key area that will help improve a data center’s PUE is the cooling system. Data centers typically consume the most energy on powering and cooling the equipment. In order to help with that, there are a variety of solutions to keep data centers cool. There are CRAC (computer room air conditioning) units, hyper CRAC units, or systems where cold outside air is used instead of a cooling system. Many are turning to hot-aisle containment and cold-aisle containment systems to increase cooling efficiencies and reduce costs.

Cooling Systems

Maysteel Colling SolutionsAisle containment systems increase the cooling capacity and improve cooling unit efficiency while allowing for higher data center temperatures by keeping the air contained. The higher temperatures allow for lower fan speeds, increased temperatures in chilled water, and the use of free cooling, all of which save energy. Aisle containment systems are also more efficient than rear-door cooling units, which allow more hot and cold air to mix.

The purpose of a Cold Aisle Containment System (CACS) is to contain cold air and keep hot air out. Installing end-of-row doors, aisle ceilings or overhead vertical wall systems prevents hot air recirculation, while redirecting cold air into the air intakes of data servers. A CACS ensures IT equipment is cooled within a manufacturer’s needs and can also ensure increased operating efficiency by removing hot spots. Having no hot spots means there is more space throughout the data center for cabinets.

The opposite of CACS is a Hot Aisle Containment System (HACS). HACS prevent hot and cold air from mixing. HACSs send air into the intake ducts of the air conditioning system to be recycled into cold air. In some cases, hot aisle containment can double the cooling capacity of the CRAC unit, which cuts costs and increases efficiency, lowering the PUE score. DAMAC engineers typically recommend a HACS over a CACS, as the cost and energy efficiencies associated with a HACS generally are greater. Many data centers select their aisle containment systems based on their current data center construction.

Additional Ways to Improve Your Data Center’s PUE

Consolidating and replacing inefficient servers and repurposing or even powering down servers that are no longer used. Invest in more energy-efficient servers, UPSs and PDUs, especially ones that are ENERGY STAR rated.

The demand for high-power data centers will continue to grow. Meanwhile, the focus on energy efficiency is also increasing, and that demand is putting pressure on data center designers and manufacturers to reduce power consumption and increase efficiency. If you’re looking at reducing the costs of running your data center and lowering your PUE, these cooling and data center design can be a great starting point.

Are you looking to learn more about how cooling can improve your Data Center’s PUE? Are hot and cold aisle containment systems right for your data center? Click here to read the whitepaper.

©2020 Maysteel Industries, LLC

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