The survey (pdf) of 115 people working on data centers of 2,500 square feet or larger found 49 percent using economizers, a type of cooling that takes advantage of favorable weather conditions to cut down on energy use, and 24 percent are considering implementation. Those using economizers found an average of seven percent savings on maintenance costs.
The survey participants included facilities managers, engineers, IT professionals, executives and project managers.
There are two basic kinds of economizers. Air-side systems blow fresh air into the data center and discharge hot air back out, or use air-to-air heat exchangers. Water-side systems remove heat from chilled water loops using a heat exchange with outside air. In the survey, the most popular types of systems were direct outside air (39%) and chilled water with a water-cooled chiller (27%).
Those who had considered but not installed economizers cited the difficulty of retrofitting an existing facility as the biggest factor in their decision. Almost three-quarters of economizers are installed during new construction as opposed to retrofitting. Reliability was another big concern for those deciding against economizers.
Those who have not even considered economizers say this is primarily because of climate unsuitability and initial costs.
But one third of respondents who had installed economizers said they had no problems with their system. In fact, satisfaction levels were 7.46 and above (out of ten) for economizers’ reliability, financial savings, coordination with mechanical cooling mechanisms, maintenance costs, and actual time in use.
For those who said they had had difficulties with their economizers, initial costs were the biggest issue.
The survey found that economizers created no statistically significant difference in power usage effectiveness, backing a finding by the EPA in its 2009 Energy Star Data Center Infrastructure Rating Development Update. The Green Grid said it plans to examine economizers’ impact on PUE in more detail.
The organization said certain obstacles to uptake of economizers cannot be easily addressed. But adoption could be increased if decision-makers learned more about economizers’ return on investment, dependability and ease of operation, the Green Grid argued.
The 2010 version of the ASHRAE 90.1 standard on energy efficiency now requires economizers as a baseline installation for data centers in much of the U.S., and the Green Grid noted that regulations will continue to be a driver for economizer installation.