The impact of Displacement Ventilation with Breathing Zone Air Supply onInfectious Spread in Office: Field study and CFD simulation

Division of Global Architecture, Graduate School of Engineering, Osaka University, Osaka, Japan,

^* Wakako NAMBA : namba_wakako@arch.eng.osaka-u.ac.jp

Abstract

Office spaces where many people spend long times need effective ventilation systems to prevent infections. This paper suggests a new ventilation method called “Displacement Ventilation with Breathing zone Air Supply” as a way to achieve that. In conventional displacement ventilation, all supply air is provided from the floor level. However, in the new system, supply air is provided from both breathing zone (breathing zone air supply) and floor level (floor level air supply). This new system aims to improve air quality of the breathing zone by controlling air flow of breathing zone air supply which is modified its supply condition considering the temperature stratification. The system also aims to be energy efficient due to increasing the average temperature of supply air. In this research, the performance of this ventilation system was examined through a full-scale experiment and CFD analysis assumed an office space. The results were discussed in the temperature and concentration distribution. The results showed that the temperature stratification was formed even when air was supplied in the breathing zone. By optimizing the air supply conditions, the new ventilation system is considered to be more effective than conventional displacement ventilation to prevent infectious diseases.