Summer dynamic thermal environment for isolated atrium in the severe cold region: On-site measurement and numerical simulation

The widespread construction of atria with skylights is a recent architectural trend in modem society for natural illumination and aesthetics. However, a handful of studies have revealed that in the severe cold region there are probably unpleasant overheating and obvious thermal stratification during summertime. Moreover, when the atrium is 'isolated' from the ambient environment, indoor air is almost trapped and becomes stagnant. In this study, on-site measurements were conducted to investigate the dynamic changes in air and wall surface temperature profiles on the horizontal and vertical planes of an atrium in Harbin, China. The maximum air temperature reached 34 degrees C, and the corresponding non-uniformity coefficient was as high as 0.22. A velocity propagating zonal model was then studied and expanded to the atrium, in which a momentum equation is implemented to describe kinetic energy conservation, transformation and dispassion of air in a constructed airflow network. A solving procedure for the zonal method was newly developed. Some key issues, such as thermally stratified wall boundaries, were further discussed. Comparing the simulated and measured results over the day with a probability of 95%, the spatial maximum air temperature deviation is 0.14 +/- 0.24 degrees C, and the Spearman correlation is 0.95 +/- 0.018.