A recent white paper from APC-Schneider Electric notes that that the choice between direct versus indirect air economization in the data center depends on each system's specific benefits, plus geographic locations, capital costs, operating costs, and availability risks.
"A [data center] cooling plant operating in economizer mode is one of the biggest opportunities to save energy and lower carbon footprint because the energy-intensive, refrigerant-based cooling components like chillers and compressors can be eliminated, shut off, or operated at a reduced capacity," contends the paper's executive summary. "A Green Grid survey of data center operators showed that use of economizers will result in saving an average of 20% of the money, energy, and carbon for cooling when compared to data center designs without economizers."
"Both direct and indirect air economizer modes have pros and cons," continues the summary. "An ideal economizer mode takes advantage of a wide range of outside conditions to maximize the number of economizer mode hours, has the lowest operating and capital cost, while presenting the fewest risks to data center availability."
Nonetheless, the paper's authors conclude that "while both approaches can cool a data center with little to no use of mechanical cooling, indirect air economization uses less energy in the majority of locations around the world."
"The direct approach can have a lower capital expense but presents more availability risks compared to indirect," notes APC-Schneider Electric. "The added capital expense of mitigating these risks diminishes the appeal for direct air economization. Therefore, in general, indirect air economization is the recommended approach."
View/Download the white paper.
