Abstract/Summary

During the heating season with high-frequency infection events, an appropriate ventilation method is critical to a healthy hospital environment. In this study, impinging jet ventilation (IJV) was proposed to reduce cross-infection risk in a two-bed ward for winter heating. An Eulerian-Lagrangian approach validated by experimental data was employed to simulate exhaled particle dispersion. Using a full factorial design method, under air changes per hour (ACH) of 6 – 15 h-1 and supply air temperature (Ts) of 24 – 30°C, the effects of supply air parameters on particle dispersion was analyzed. A correlation model was subsequently established to delineate the relationship between supply air parameters and particle elimination. With an orthogonal-based grey relational method, this study compared the contribution and significance of supply air parameters and two uncontrollable factors (i.e., source location and outdoor air temperature), and then optimized the supply air parameters of IJV. The results indicated that the contribution percentage of supply air parameters was higher than 70% for particle removal and residence time. With an appropriate supply air parameter, the airflow of IJV could comply with human body plume, enhancing removal of fine particles (≤ 20 μm). However, with a low Ts (lower than 26°C) or an excessive ACH (more than 12 h-1), the number of fine particles moving upwards might be reduced. To achieve a better performance in preventing cross-infection, ACH and Ts of IJV were recommended to be set at 9 h-1 and 28°C, respectively. The findings were expected to provide guidance for ward ventilation design.