To push the boundaries of innovation and lead the way in sustainability, Infosys undertook a case study of a Tier 3, 300kW data center in Bangalore, India to show that PUE of less than 1.1 was attainable using direct evaporative cooling with rear door heat exchangers (RDHX). The PUE of 1.06 was achieved with the initial installation, but the PUE increased due to excessive air leaks around the RDHX caused by movement and changes in the rack mounted components. This resulted in air leaks bypassing the RDHX and necessitating the use of the chilled water loop to reduce the water temperature through the RDHX. The effectiveness of current refinements will be presented as well as the resultant PUE. In addition to the design used in this case study, a related alternative configuration will be discussed which will allow more flexibility in the loading of the data center racks while maintaining the low PUE and passive nature of the liquid-air heat exchangers.
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