A novel convection and radiation combined terminal device: its impact on occupant thermal comfort and cognitive performance in winter indoor environments

Abstract Personal comfort systems usually use a single heat transfer mode to improve local thermal comfort by only stimulating one local body part. A novel hybrid convection and radiation combined terminal device, which could be used both in summer and winter, was proposed. A total of sixteen human subjects took part in a winter subjective experiment to test its performance on the improvement of occupants’ thermal comfort and cognitive performance in winter. Occupants’ thermal comfort, air movement perception, eye dryness and cognitive performance were investigated. The results showed that 88% of the subjects accepted 16℃ room temperature. 0.4 m/s air speed to face and abdomen parts is acceptable when convective airflow temperature is 4.5℃ higher than room temperature. No dry eye discomfort was reported while using a controllable device. Furthermore, subjects’ cognitive performance, including self-evaluate work performance, math (mental performance) and typing performance (dexterity), could be significantly improved by using the novel device. Energy efficient thermal comfort can be achieved by less intensifying ambient heating temperature to 16℃ in winter.