Impact of shaft design to thermal comfort and indoor air quality of floors using BIM technology

When studying Indoor Air Quality (IAQ) in commercial buildings by conducting Computational fluid dynamics (CFD) simulations, the solution domain usually includes studied rooms or floor volumes only. The air shafts connected to the studied room and floor were rarely considered. Previous studies, which focused on analysis and simulation of air movement inside ventilation and exhaust shafts, seldom considered how the corresponding air movement affects the connected floors. Field measurement cannot be conducted in inaccessible tenant areas to support CFD simulations. The current practice to calculate solar heat load and distribution for CFD simulation with surrounding buildings included is computationally expensive. The objective of this study is to develop a methodology to investigate how velocity variations along the fresh air shafts affect thermal comfort and IAQ of multiple floors under limited obtainable field measurements. Steady-state CFD simulations were conducted on fresh air shafts and office floors of a typical commercial building. Building Information Modeling (BIM) technology was applied to create models to represent the geometry of fresh air shafts and office floors accurately. In addition, BIM technology not only supports CFD simulations but also provides geometric, semantic and location information for solar analysis. The CFD results were validated using measured results. The impact of shaft design changes on the ventilation performance of the shaft and the indoor air quality on the floors was investigated using validated models. In the case of dividing the shafts into two parts, the overall fresh air distribution, thermal comfort and indoor air quality were improved.