An analysis of the effects of ceiling height on air distribution in data centers

Abstract

In this study, computational fluid dynamics (CFD) models are used to evaluate how ceiling height affects the overall performance of the air distribution system within a data center environment. First, an underfloor air delivery system is examined while keeping all operational parameters constant and varying only the clear space height. Then, the performance of the same system is evaluated with a dropped ceiling while varying the clear space height. Finally, an overhead air distribution system is considered, keeping all operational parameters constant while varying only the clear space height. The performance of each system is evaluated using dimensionless parameters developed previously by others. These indices, supply heat index (SHI) and return heat index (RHI), when used to examine the temperatures at the inlets to the equipment inside the cabinets and at the air handler or computer room air-conditioning unit (CRAC) inlets, provide a measure of how much recirculation and bypass occur within the data space. © 2006 ASHRAE.