For Large Data Centers, Indirect Economizer Cooling Makes Sound Business Sense [OG Partner]
At this point in the evolution of data centers, use of economizer mode cooling technology is pretty much standard, at least for large data centers such as those owned by colocation and cloud providers as well as Internet Giants like Microsoft and Facebook. The only real argument is about what basic type of economizer mode to use: direct or indirect.
When air economizers first came on the scene, most companies favored the direct approach. Direct air economization, also known as “fresh air,” is when you take fresh outside air and send it through a series of filters and/or wetted media directly into the data center for cooling. The simple design of the direct approach makes it highly efficient from a power perspective because it takes only a series of fans and louvres to get the job done – at least while ambient outdoor temperatures are sufficient.
But direct cooling has a couple of downsides that tend to muddy the equation. Chief among them is the filtration required to ensure no airborne contaminants get into the data center. Those filters have a tendency to get clogged, requiring frequent maintenance. In areas that suffer from heavy pollution, that can be a deal-breaker. And if there happens to be a wild fire, chemical spill or other pollutant in the area, that can likewise require the data center to disable the economizer mode altogether and shift to mechanical cooling.
What’s more, direct cooling is highly subject to outside moisture changes. Overly dry outside air requires added humidification, while high humidity necessitates dehumidification – both of which reduce efficiency.