Assessment on rack intake flowrate uniformity of data center with cold aisle containment configuration

Abstract

The present paper investigates the rack intake flowrate uniformity in a simulated container data center subject to cold aisle containment (CAC) configuration. Based on a novel flowrate uniformity index (FUI) in prior study, a strong flowrate mal-distribution at the rack inlets is observed by examining the standard deviation of FUI (sigma(FUI)). When raising the supplied volumetric flowrate from 2.52 m(3) s(-1) to 3.40 m(3) s(-1), the outlet temperature of each cabinet is remarkably reduced. Meanwhile, applying a gradient fan speed for cabinets can reduce the sFUI by 19.5-34.0%. However, the mal-distribution for the top and bottom cabinets is still prominent. In essence, adding air supply flowrate or changing rack intake layout show limited improvements and may even have potentially deleterious effects. To tailor the mal-distribution problem, a novel configuration featuring the concept of Coanda effect is proposed. A triangular deflector is implemented to guide the cold air sweeping through fan trays in front of the data rack. The sFUI can be effectively reduced by about 51.3-62.0% compared to the original design, showing a significant improvement on the intake flowrate distribution for all racks.