Study on Different Locations and Shapes of Outlets for Green Building Design

In recent years, the levels of air tightness and insulation of residential houses are becoming better for energy saving and, hence, living comfort has been improved. However, the problem of dust particle, due to the lack of ventilation rate, has become increasingly serious. The term `dust particle' includes the spore of mold or corpses and the feces of mites and so on, which are the cause of allergy, asthma and unspecific hypersensitivities. In this study, experiments and simulations were performed to study the flow and diffusion fields affected by different locations and shapes of outlets in green building. Two kinds of ventilation strategies, ceiling exhaust and slit exhaust, were considered. In the experiments, the characteristics of airflow within the whole room are generally similar except airflow close to the outlet. In the simulations, the characteristics of airflow are similar for both experimental and simulation results. And the volume-averaged concentration of dust particle in the breathing zone increased once before it gradually decreased. From the data we can also conclude that the volume-average concentration of dust particle in the breathing zone using slit exhaust strategy is lower than that of ceiling exhaust type in green building.