Utilization of an evaporative air cooler to achieve thermal comfort in Thailand

Evaporative air coolers are widely accepted for outdoor use in the tropical climates of Thailand. However, their contribution to achieving indoor thermal comfort is still undetermined. The purposes of this study are to determine the thermal comfort level achieved by evaporative air coolers and identify variables affecting thermal comfort when using an evaporative air cooler indoors in the tropical climate of Thailand. The results of a questionnaire that asked subjects about thermal comfort when exposed to evaporative cooled air were compared with the results of participants exposed to natural air. A multiple regression model identified variables affecting thermal comfort. This research successfully determined the thermal comfort level achieved by evaporative air coolers of −0.6 (slightly cool) on the thermal sensation scale, which is lower than the level of 0.0 (neutral feeling) achieved by fans. The recommendation is that evaporative air coolers with a high velocity of 1.4 m/s be used indoors to avoid discomfort from the too damp air. The results of the regression analysis demonstrate that air temperature and velocity are the two most influential variables affecting thermal sensation in the application of evaporative air cooling in Thailand.