Effect of elevated air temperature and air velocity on thermal comfort and cognitive performance in the tropics

Long-term experiments were conducted to investigate participants' thermal comfort and cognitive performance in fan-assisted cooling environments in tropical Singapore. Sixteen local students were exposed to various air temperatures (27-30 degrees C) and air velocity conditions (0.2 m/s, 0.9 m/s, 1.5 m/s, and 2.0 m/s). During the experiment, thermal comfort surveys, wearable devices, cognitive performance tests, and adapted NASA-TLX surveys were used to collect the participants' thermal comfort, physiological responses, cognitive perfor-mance, and self-estimated workload. The results showed that thermal comfort can be maintained from 27 to 30 degrees C with elevated air velocities. The participants' mean skin temperature increased significantly (p < 0.05) with an increase in air temperature and decreased significantly with an increase in air velocity. For the cognitive performance test, participants' overall relative performance scores in the warm sensation were 7.4% (p < 0.001), 8.4% (p < 0.001), and 7.4% (p < 0.001) lower than the cool, slightly cool, and neutral sensations, respectively, while the slightly warm sensation was 4.3% (p < 0.01) and 3.3% (p < 0.05) lower than the slightly cool and neutral sensations, respectively. In contrast, no negative effects of cool or slightly cool sensation s were observed in the cognitive performance test results. Finally, participants' cognitive performance was not affected by elevated air temperature and air velocity when their thermal comfort was maintained. These results support the design and use of elevated air temperatures and air velocities in the tropics.