Optimizing Ventilation Systems for Dual Objectives: Enhancing Thermal Comfort and Controlling Droplet Dispersion

Optimizing the form and parameters of ventilation systems is crucial for enhancing the microenvironment around individuals, with a primary focus on human comfort in ventilation design. Additionally, controlling exposure concentrations of respiratory droplets is an essential strategy for dealing with respiratory infections. Therefore, a thorough examination of the relationship between the form and parameters of ventilation systems, human comfort, and the dispersion of droplets becomes particularly significant. This study utilizes computational fluid dynamics (CFD) to optimize ventilation systems, focusing on enhancing individual comfort and reducing droplet dispersion in indoor environments, particularly in cruise cabins where the microenvironment significantly impacts passenger well-being. It evaluates three ventilation systems: orifice plate ventilation system (OPVS), ceiling mixed ventilation system (CMVS), and sidewall mixed ventilation system (SMVS). Employing the Entropy-weighted TOPSIS method, it optimizes ventilation temperature and relative humidity across 20 combinations to achieve optimal thermal comfort and airflow uniformity. The findings indicate that OPVS offers the best thermal comfort and uniform airflow, with an ideal configuration at 21 °C and 60% relative humidity. It also investigates the placement of air purifiers under the optimal ventilation configuration (OPVS), revealing that positioning them near the breathing zone reduces droplet concentrations by 42.6%, while central placement achieves a reduction of 40.1%. This suggests central air purifier placement for practical applications, balancing droplet concentration reduction with minimal occupant disturbance. This work contributes to understanding ventilation strategies for managing respiratory diseases and ensuring indoor comfort.