Ventilation Design for KMUTT’s Classrooms

Most classrooms in Thailand are equipped with a vapor compression cooling system without proper ventilation, resulting in the accumulation of carbon dioxide (CO2) and other pollutants. CO2 is one of the indoor air pollutants emitted by humans. Adequate ventilation plays a major role in reducing the accumulation of pollutants, especially in a classroom where human density is quite high. This research aims to study the airflow pattern and appropriate ventilation rate of the sample classrooms in King Mongkut's University of Technology Thonburi. CO2 released from the human body is selected as the representative for studying pollutant distribution in the classroom. The mathematical model created by COMSOL Multiphysics® Version 5.5 is applied to design the position of ventilation fans, airflow characteristics, and ventilation rate. The study found that installing a ventilation fan together with sufficient internal fans enhances the air circulation in the classroom and keeps the CO2 concentration under 1000 ppm. The ventilation fans should be installed between the air conditioning units and opposite the air inlet. Installing a ventilation fan opposite the air conditioning unit will create whirlwinds and widely distribute CO2 in the room. Installing a ventilation fan under the air conditioning unit will reduce the ventilation performance, resulting in the accumulation of CO2 at some point.
Keywords: Ventilation; Air Pollution; Classroom Design