INDOOR AIR QUALITY OF ZERO ENERGY BUILDING'S MULTIPURPOSE CLASSROOM

Abstract

Given the warm and humid climate of Singapore, an average Singaporean spends significantly more time indoors than outdoors. Since most indoor spaces are being airconditioned, great emphasis is being placed on air-conditioning and indoor air quality. In the past, classrooms are naturally ventilated, but in the recent years, there has been a trend with increased usage of air-conditioning in school facilities. With the increased usage of airconditioning in schools, students are likely to spend more time in air-conditioned spaces. From the educational standpoint, the indoor air quality and ventilation in school buildings can affect the health of the students and indirectly affect learning performance. The large thermal difference between outside and indoor air in Singapore’s tropical climate leads to a high energy-penalty from cooling and dehumidification. Hence, it is a challenge to seek an optimal design to balance the energy consumption and cost and indoor air quality. As such, a new air-conditioning system known as the Single Coil Twin Fan (SCTF) system which is based on cooling and ventilation on demand is invented to provide a better the indoor environmental condition without incurring huge energy costs. This study seeks to address the absence of work on indoor air quality and thermal comfort of air-conditioned classrooms using the SCTF system by evaluating the performance of the SCTF system adopted in the multipurpose classroom of the Zero Energy Building.This research comprises of both objective measurement and subjective assessment to ensure a holistic evaluation of the indoor air quality. Experimental results showed that the IAQ parameters are within threshold limits with the exception of biological contaminants. The air velocity in the classroom is also found to be inadequate. Similarly, subjective assessment also showed that the air was perceived to be still and there were dissatisfaction with the existence of odour. Despite that, results indicated that the occupants are satisfied with the indoor air quality of the multipurpose classroom. Lastly, appropriate recommendations such as the installation of ceiling fan to operate simultaneously with the air-conditioning system have been proposed to improve the indoor air quality of the classroom.