Optimizing performance of ceiling mounted personalized ventilation system assisted by chair fans : assessment of thermal comfort and indoor air quality -

Abstract

This study investigates and optimizes the performance of ceiling mounted personalized ventilation (PV) system when assisted with chair-mounted fans. Detailed computational fluid dynamics (CFD) simulations were performed to study the velocity, temperature, and CO₂ fields around the microclimate of the occupant. The CFD model was integrated with a bioheat model to determine the corresponding segmental skin temperature and local and overall comfort and sensation. The CFD model was validated experimentally using a thermal manikin in a climatic chamber. Segmental skin temperature, velocity field, and CO₂ field were validated experimentally. The predicted values and the measured values showed good agreement. The validated CFD model was used to optimize the height of chair-fan and the fan flow rate for the best combination of indoor air quality and thermal comfort. The chair fans configuration to achieve best thermal comfort and best IAQ occurred at different fan heights. The optimal fan height and flow rate for best thermal comfort were 40 cm above floor level and 10 L-s, respectively. However, the optimal fan height and flow rate for best air quality were found to be 50 cm above the floor level and 10 L-s, respectively. At this configuration, the chair-mounted-fans were able to reduce the thermal plumes and improve the performance of the PV system by nearly doubling thermal comfort and ventilation effectiveness. The use of chair mounted fans permitted achieving energy savings up to 17percent when compared with conventional mixing ventilation system.