Effects of natural ventilation on indoor thermal comfort in a residential house constructed with reinforced concrete wall

Abstract This study aims to investigate the effect of natural ventilation on the thermal performance of a double-story end-lot unit residential house constructed with reinforced concrete walls and structure in Kluang, Johor. Field measurement was conducted in the master bedroom of the house. Five ventilation cases were investigated which are night ventilation (case 1), no ventilation (case 2), day ventilation (case 3), day ventilation with fan (case 4), and night ventilation with fan (case 5). The measured data were indoor air temperature, outdoor air temperature, indoor relative humidity, outdoor relative humidity, and globe temperature. Then, the thermal comfort assessment was conducted based on the adaptive thermal comfort equation for hot-humid climate for all cases. The results show that the mean indoor temperature for all cases is in the range of 29°C to 31.5°C which indicates a high indoor air temperature. Furthermore, the analysis of air temperature difference between outdoor and indoor (out-in) for different natural ventilation modes showed that the indoor thermal conditions of the master bedroom were not significantly different when compared between cases. In the thermal comfort assessment, the night ventilation case (case 1) provided the most comfortable hours during the measurement with a range of 11 to 35.4 %, thanks to the lower outdoor climate conditions at night compared to the other cases. Overall, in this study, the effect of natural ventilation modes on the indoor thermal condition of a master bedroom in a residential house with concrete walls and structures was found not significantly different in the performance of air temperature reduction and comfort hour improvement when compared between cases.