Numerical investigation of data center raised-floor plenum

Data center raised-floor plenum effectiveness is numerically investigated using a computational fluid dynamics (CFD) package to determine the most appropriate data center raised floor plenum height (size). The current study considers raised floor plenum height between 30.5 cm and 152.4 cm (12-60 inch) with the standard 15.2 cm (6-inch) increment while maintaining the supply airflow rate constant. Three factors are considered for optimum plenum size: the individual airflow rate from each perforated tile, the level of airflow rates uniformity between different perforated tiles and the top rack inlet air temperature at 2.13 m (7-ft) above the raised floor. The results show that raised floor plenum with height of 76.2 cm (30-inch) or higher had the most uniform airflow rates through the perforated tiles and most uniform temperature across the top of the racks. The findings also indicate that the uniformity of the static pressure inside the plenum increases with plenum height. The current results show that data center plenums with height range of 76.2-91.4 cm (30-36 inch) are found to be the best option based on the current thermo-fluid considerations however thermoeconomics analysis should be addressed in future work.