Four Best Practices for Economizer Cycles in Data Centers

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As United Metal has worked with end users and consulting engineers in designing data centers over the last few years they have become very familiar with the industry’s best practices.  While best practices do not help you make technological advances or gain a competitive edge over others they do ensure that your data center is taking advantage of proven standards that others have benefited from.  One area of best practices that the ASHRAE TC 9.9 committee has summarized well is in the area of economizer cycles.  Four of the best practices that TC 9.9 suggest are as follows:

  1. Taking advantage of economizer cycles is a great way to bring significant OPEX savings to a facility due to the reduction in energy needed to provide adequate cooling.  The one caveat that end users must remember with regards to this is location, location, location.  In other words, a data center in Colorado that has a fairly low wet bulb is going to be able to take more advantage of the prevaling weather conditions than a facility on the coast of Florida.
  2. Evaporatively Cooled air side economizers provided clients with the greatest annualized utilization.
  3. The economizer control scheme needs to be an integrated one in order to allow for partial use of the economizer cycle and thus increase the number of hours that it can be used each year.
  4. Any time the inlet supply temperature can be raised in a facility it increases the number of cooling hours in economizer mode.  However, this should be analyzed carefully as there are trade-offs that need to be considered between server fan energy and the inlet supply temperature.*
*Adapted from:  American Society of Heating, Refrigerating and Air-Conditioning Engineers. (2008). Best practices for Datacom Facility Energy Efficiency. Atlanta, GA: American Society of Heating, Refrigerating, and Air-Conditioning Engineers.