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|Impact of Active Tiles on Data Center Flow and Temperature Distributions|
|Keywords: Data Center Thermal Management, Active Tiles, Local Cooling Solutions for Data Centers|
|Localized hot spots pose a major problem for data center thermal management. The current response to hot spots is a discrete increase in server fan speed to draw in more cold air locally. Yet ensuring that cold air is available everywhere in the data center at all times would require over-provisioning the data center, while a lack of cool air would cause recirculation, making the hot spot worse. The desired approach is instead to provide additional cold air only where and when it is required, and avoid overcooling the entire data center. Active tiles, with integrated fans, increase the local volume flowrate by redistributing the cold air supplied by the CRAC to the underfloor plenum. This work examines the air flow and thermal characteristics using active tiles for their potential in efficiently and economically eliminating hot spots in data centers. Experiments were conducted to determine flow and thermal distributions, as a function of the CRAC (computer room air conditioning) unit blower and active tile fan speeds, both for a single tile/rack combination as well as for a complete aisle populated with active tiles. A comparison was then made with similar results for passive (generic) tiles with comparable effective porosity. Measurements quantifying cross-correlation factors representing the effect of active tile on adjacent tiles is presented. The power consumed by the active tiles in terms of W/m3 air at the tile outlet is compared with that for passive tiles. Results indicate that the power consumption per unit air flow is lower when using a configuration consisting of a complete aisle of active tiles. Based on the experimental observations, we propose a control framework that uses the active tile fan speed as a process variable to provide the requisite air flowrate to cool the hot spot, while reducing power consumption by the server fan, and reducing data center energy consumption.|
|Jayati Athavale, Graduate Research Assistant
Georgia Institute of Technology