Monitoring and modelling indoor air quality and ventilation in classrooms within a purpose-designed naturally ventilated school

This paper investigates the performance in use of thermal passive ventilation stacks in the classrooms of a school during the summer period. Measurements of air temperature, carbon dioxide (CO ₂) and air velocity were carried out from which ventilation rates in the classrooms and stacks were calculated. It was found that the airflow through the passive stacks was a significant proportion of the classroom air exchange rate and metabolic CO ₂ was lower in classrooms with passive stacks. The predictions of a multi-zone airflow computer model were compared with measured values. Multi-zone modelling indicated that passive stacks could significantly increase ventilation in classrooms, which would otherwise be ventilated via single side ventilation through openable windows on one external wall. It was found that if the zones are accurately represented, multi-zone modelling is able to provide a good indication of the general trends of airflow rates both for the whole classroom and the flow through passive stacks.