Pushing the Data Center Boundary Blog: Is Fresh Air really good for everyone?

There’s been a lot of press over the last few years about “Google type” data centers that use 100% fresh air to perform cooling.  In many cases, these designs bring fresh air directly in from outside and may use some type of evaporative cooling to assist in tempering the air.

In general terms, these data centers are willing to accept a wider variation in the ambient environment as well as accept any possible contaminants carried in with that air.  Obviously filtration can help but you can only filter so much – relying on filters to insure data center uptime can be risky in the event of a major nearby fire, sandstorm, or some other event that can clog filters and leave you open to a single point of failure.

The question I ask is whether this is a good idea for typical data centers?

I get asked this question often and I usually get a mixed feeling from many data center operators.  There tends to be a mentality of  “I’m not sure I’m like ‘Google’, even though I’d like to lower energy costs.”

To be clear, I’m not trying to bash the ‘Google type’ data center – they make a lot of sense for their intended application (those guys at Google are pretty smart!).  However, the fact is that many data centers today are more limited in their ability to leverage a fresh air design.   For instance, if the data center isn’t close to an exterior wall or roof than it can be overly complicated to get the fresh air into the IT Room.  What if it’s a small data center in the middle of an office building?

Our data center in St. Louis is an example where significant work would have to occur to the building to utilize 100% fresh air.  And being business people, we have to look at whether it’s worth the expense.

Not to mention that many people I talk to are inherently a little more risk averse than ‘Google type’.  Small issues like a potential chemical spill or pollution in the air outside getting brought directly into the IT room are concerns I have heard raised.  I had one data center manager tell me that no matter what ASHRAE says, he’s not going to allow the temperature to vary too much in his data center.  It’s the old mentality of “I won’t get fired if the electric bill is high but I will if the application goes down.”

We developed our Ecobreeze solution to separate the outside air from the inside air by using an air-to-air heat exchanger.  We did this in response to our research showing a large concern by the mainstream market to bringing in fresh air directly.  The irony is that now when I present Ecobreeze at conferences I have people challenging me during the Q&A session on how much it costs to run the air-to-air heat exchanger implying that it’s inefficient.

It’s interesting to me that I have yet to see in one of the presentations someone stand up publicly and say they don’t think fresh air is a good idea.  Usually they come up to me afterwards and discuss their concerns one on one.  “I didn’t want to say anything in front of the group but I’m not risking my job on 100% fresh air”.  It’s a fascinating dynamic to experience.

I’m really not sure whether it’s smart to be aggressive or conservative with the use of 100% fresh air.

Regardless, I do believe that most data centers can probably get a lot more efficient by doing some basic things well, such as utilizing air containment strategies, right-sizing IT load against power and cooling capacity, ensure economization is programmed and operating properly, etc.

Time will tell but I expect we will still see water in a lot of data centers for the foreseeable future.  Fresh air or water – take your pick.


Please follow me on Twitter @KevinBrown77


About Kevin Brown:

Kevin Brown is Senior Vice President of Innovation and Chief Technology Officer for the €3.7 billion IT Division at Schneider Electric. In this role, he is responsible for driving innovation and managing the R&D portfolio for the IT Division as well as driving the overall Schneider Electric portfolio strategy for the Data Center market. Prior to this position Kevin served as Vice President, Data Center Global Strategy and Technology. Kevin has also held numerous senior management roles in product development, engineering, and software development in the power electronics and HVAC industries. He holds a Bachelor’s of Science in Mechanical Engineering from Cornell University.



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  • Fascinating perspective Kevin. Thanks for sharing your experiences and giving us a bit more to ‘chew on’ with regard to the fresh air data center cooling debate. I’m wondering if you or any of your readers have experienced any regional bias (North America vs. Europe vs. China, etc.) toward fresh air vs. chilled water cooling in the data center?

    • Hey Kim,

      Fresh air is most compelling in climates that are not hot and humid. Hot and dry can be OK.

      Unless you do some clever things with evaporation….

      Thanks for the comment.


  • I work for Green House Data and we also utilize free cooling. It works great for reducing energy costs, which is a high priority for us since we’re a green data center. The previous commenter asked about international locations and how they utilize this type of cooling. However, it can vary even in the US and should be considered by temperature/humidity by region. For example, in Wyoming, the humidity is very low, so when the evaporative cooling kicks in, it can add moisture into the data center, which is a benefit in our dry environment. However, in a city where humidity levels are high, it may not be a good solution, as the added humidity can negatively effect server functions.

    • Couldn’t agree more Kristen.

      Thanks for the comment and the clarification,


      • John Wesley Shannon

        12 years ago

        Try Seattle in the winter, 200% plus humidity, well it feels like it.

  • John Wesley Shannon

    12 years ago

    In times past, and sometimes present, room air conditioners would have an economizer that was tied to a special thermostat that sensed heat and humidity and when outside air had a lower sensible reading then inside air the dampers adjusted to take outside air. This was available on most large units. also there was a push at one time to take the hot air out of the drop ceilings due to the heat from lights. However, as modern lighting energy continues to be reduced, this has been less of a concern, Regardless there should always be a certain amount of fresh air, so if there is a pollution problem, whether the is 10% or 100% fresh air, outside pollution is coming into the room unless the filtration system catches it,.

  • Joy Jacob CDCP

    8 years ago

    Fresh air with high humidity is not acceptable for Data center

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