Effect of an Air Cleaner Based on Age of Air Distribution Measurement Using the Dynamic Steady-State Concentration

This study aims to determine the range of the effect of an air cleaner in indoor environments. The age of air is often used to evaluate the ventilation performance in indoor air environments, and step-down tracer gas methods are widely used in open-air systems in ventilation rooms. However, conventional experimental methods cannot be used to measure the age of air in air recirculation systems such as an air cleaner that do not have a ventilation system. Previous studies have shown that the dynamic steady-state concentration correlates with the equivalent steady-state concentration in the ventilation room of an open-air system. In this study, we investigated the possibility of determining the age of air by measuring the dynamic steady-state concentration generated in a real space. First, we used the tracer gas experimental technique based on the dynamic steady-state concentration to measure the age of air in a real space when an air cleaner was used. We then performed simulations to confirm the age of air distribution obtained from the tracer gas experiment using computational fluid dynamics (CFD) analysis. A comparison of the experimental and CFD analysis results showed that the effect of an air cleaner covered the entire room.