Effects of Air Terminal Types on Performance of Stratum Ventilation

This chapter aims to investigate the impact of various air terminal types on the design and performance of stratum ventilation. Experimental and numerical methods are employed to examine four specific air terminal types, i.e., circular diffusers, square diffusers, perforated diffusers, and double deflection grilles. The experiments are conducted under different experimental conditions to assess thermal sensation and comfort. Six performance indicators are utilized, i.e., airflow pattern, temperature distribution, air diffusion performance index, thermal sensation, comfort feedback, local mean age of air, and CO₂ concentration. The findings demonstrate that the airflow pattern is significantly influenced by the type of air terminal. All four diffuser types exhibit effective air diffusion performance, and circular and perforated diffusers are particularly successful in providing thermal comfort. In terms of air quality, the circular diffuser displays the highest local mean age of air, while the CO₂ concentration in the breathing zone ranks second lowest and exhibits the greatest uniformity. Consequently, the circular diffuser is considered a favorable choice for stratum ventilation.