Investigation on temperature range for thermal comfort in nonuniform environment

Abstract

This study uses the previously adopted local ventilation air-conditioning mode to study the effect of temperature on thermal comfort for subjects. Three room temperatures (26, 28, 30°C (78.8, 82.4, 86°F)) and three local ventilation temperatures (20, 26, 28°C (68, 78.8, 82.4°F)) were used for the study. The air velocity was purposely set low for the local ventilation tests, in order to focus on the temperature combinations between the ambient and local air temperature from the local ventilation device. Eighteen subjects participated in the experiment, using the within-subjects design method. During exposure in the room, the subjects reported thermal sensation and thermal comfort accompanied by the skin temperature measurement of the subjects. The room temperature of 28°C (82.4°F) combined with the local ventilation temperature of 26°C (78.8°F) (28°Crt and 26°Clv (82.4°Frt and 78.8°Flv)) was assessed to be the most comfortable environment. Through the experiments, the neutral room temperature of 26°C (78.8°F) combined with the local ventilation temperature of 20°C (68°F) as well as the warm room temperature of 30°C (86°F) combined with 26°C (78.8°F) was found to be within the comfortable range. The results imply that compared with the traditional air conditioning mode, which creates a uniform comfortable environment by setting the air temperature to be 26°C (78.8°F), the adoption of local ventilation could improve the thermal comfort while consuming less energy.