Thermal Sensation of Thai Students in an Air Conditioned Space with a Pond Type Water Source and Air Velocity Step Change

Abstract

This paper investigates thermal sensation in an air conditioned space with and without a water source such as a water pond and small fountain in Thailand. Questionnaires were collected from experiments involving 140 subjects divided into groups of 6–14 people sitting in controlled rooms of sequences of air velocity with and without a water source. Furthermore, another 41 subjects participated in a room with a large picture of a waterfall and were later exposed to a water source. Air temperatures of 22.5–27.0 °C, relative humidity of 47.0–60.6% and air velocity of 0.00–0.20 m/s were collected around the subjects. Experimental results showed that subjects in the water source space felt more ‘slightly cool’ than those that were not. This is thought to be due to evaporative cooling. The temperature in rooms with high air velocity and water flow of 0.83 litre/hour was reduced by 0.4–1.5 °C compared to those without water. The mean votes in the space with water source were -0.76 to -1.01, lower than that of -0.26 to -0.86 in the space without a water source for every sequence of air velocity change. In the experiment with a waterfall picture, subjects found the picture refreshing but they did not feel cooler. Mean votes of -1.00 and -0.55 were obtained from the rooms with the water source and with waterfall picture, respectively.