Influence of airflow mode and airflow temperature of air conditioners on human thermal comfort

Under high-temperature environmental conditions, airflow is an effective way of regulating human thermal sensation and enhancing thermal comfort. However, there are significant differences in the effects of different forms and temperatures of airflow on human thermal comfort, and it is important to study these differences to optimize airflow selection strategies. In this study, the thermal comfort under five experimental conditions, namely, no airflow, cooled constant mechanical airflow, cooled oscillating airflow, room temperature constant mechanical airflow and room temperature oscillating airflow, is comparatively analysed using a hotter environment (28 ℃) as the experimental condition. The experimental results show that the thermal comfort vote value under the room temperature constant mechanical airflow condition is 1.61 higher than that under the no airflow condition (p<0.001), and 1.33 higher than that under the cooled constant mechanical airflow condition (p<0.001) in an indoor environment at 28 ℃. This finding confirms that the appropriate type of airflow has a significant positive effect on enhancing human comfort. It is further found that compared with the room temperature constant mechanical airflow condition, the human thermal sensation under the room temperature oscillating airflow condition decreases by 0.21 (p<0.05), suggesting that dynamic winds have an advantage in alleviating thermal discomfort and show potential to cope with higher room temperature environments. In addition, the change trend of skin temperature is consistent with the thermal sensation vote results. Compared with the room temperature constant mechanical airflow condition, the change in skin temperature of men under the room temperature oscillating airflow condition decreases by 0.61 (p<0.05), and that of women decreases by 0.81 (p<0.05). This finding provides reliable physiological evidence to support the above conclusions. This study provides a scientific basis for the optimal selection of airflow parameters in high-temperature environments, which is of theoretical and practical significance for improving the design of indoor thermal environments.