Measurement and CFD simulation of the temperature stratification in an atrium using a floor level air supply method

A glazed atrium is a common feature in shopping centres and in the lobbies of residential and commercial buildings. This research aimed to discover the vertical temperature distribution and cooling load reduction relating to displacement ventilation in atrium spaces. The air temperatures at different levels (0.1, 0.7, 1.2, 1.7, 3, 5 and 7 m), within a 25 m high exhibition atrium, were monitored. Using the measured surface temperatures as boundary conditions, three-dimensional computational fluid dynamic (CFD) simulations were performed to examine the vertical temperature distribution. Further, by using parametric studies, the influences of occupant load, equipment load, lighting load, floor and wall surface temperatures, and supply air conditions were investigated with 12 CFD simulation cases. Based on the simulation results, load reduction factors - with three grouping methods of heat sources - were then developed. Temperature stratification was present even under the condition of a low cooling load. Load reductions were lower for occupant and equipment loads than for a lighting load. The best grouping method was to consider the heat released from the floor as an individual group of heat sources, which is an indication that secondary heat from the floor should not be neglected during the design of displacement ventilation.