Ventilation and Air Quality of a Densely Occupied Multipurpose Room in an Elderly Care Center

Abstract

Older people are more susceptible to health risks from indoor air pollution, even at low pollution levels. This study aimed to improve ventilation and air quality of densely occupied multipurpose rooms in elderly care centers (ECCs). The specific objectives were to investigate the impact of different ventilation types on ventilation performance and air quality in the ECC’s multipurpose room, including mixing (MV), displacement (DV), zone (ZV), stratum (SV), and underfloor ventilation (UV); analyze the influence of ventilation on CO₂ concentration; and discuss appropriate ventilation design comprehensively considering air velocity, CO₂ level, air change efficiency (ACE), mean age of air (MAA), contaminant removal effectiveness (CRE), and predicted mean vote (PMV). First, an experimental study was conducted, and then 11 potential optimization models were proposed based on the experiment’s results. Finally, quantitative results were obtained through computational fluid dynamics (CFD) analysis. Analysis revealed that model ZV2 with wall outlets at 1.1 m and ceiling inlets proved to be the optimal ventilation type. It had fewer air circulation and stagnation areas, and it maintained its effectiveness regardless of furniture configurations or occupant positioning (caregivers and elderly people), factors that could potentially compromise airflow in other models. Compared to model ZV2, CO₂ concentrations in the sitting breathing zone of other models increased from a minimal increase of 0.2% to a substantial increase of 38.9%. Analysis also showed that the seats in the first row consistently maintained low pollutant concentration environments. These new results offer valuable insights for ECC stakeholders by assessing ventilation and air quality in crowded spaces for older people at two different breathing heights (sitting and standing).