Mist spraying is an active cooling technology used to alleviate heat stress during hot summers. However, there is limited experimental research on the relationship between ambient thermal parameters and spray cooling efficiency, as well as the transient and short-term thermal perceptions of local residents. In this study, an intermittent mist spraying system was set up, and environmental measurements, coupled with questionnaire surveys, were conducted under typical high temperature and still air conditions. The aim was to investigate the relationship among environmental factors, spray cooling effects, and dynamic improvements in human thermal perception. The results showed that higher ambient temperatures resulted in a more significant cooling effect, with a maximum value of 5.68 °C. Upon entering the spraying area, people experienced a large perceptual change, with the mean thermal sensation and thermal comfort change covering 73% and 62% of the total change ranges, respectively. This study indicated that the mist spray system can be activated if the ambient temperature exceeds 32.5 °C, helping local residents maintain a physiological state close to slightly hot and neutral comfort. These findings suggest that mist spraying can be applied in environmental design as an outdoor cooling spot to mitigate urban overheating, providing valuable insights for the application of mist spray systems in actual outdoor settings in hot-humid areas.

Mist spraying is an active cooling technology to alleviate heat stress during hot summers. There is no clear conclusion as to when mist spray should be used and its cooling potential in hot-humid regions yet. A periodic mist spraying system was set up, and environmental measurements coupled with questionnaire surveys were conducted, investigating the dynamic effect of spraying on the micro-environment and thermal perception. The results showed that elevated ambient temperatures could lead to a more substantial cooling impact, with a maximum cooling value of 5.68 ℃. The increase in thermal comfort due to the mist outweighed the decrease in thermal sensation. The study indicated that the mist spray system should be activated if the ambient temperature reached 32.5 ℃. Spraying could help local residents maintain a physiological state close to slightly hot and neutral comfort when the ambient temperature exceeded 34℃. The findings provide valuable guidance for the application of mist spray system in practical engineering scenarios in hot-humid areas.

Cs_0.33WO₃ (CWO) is a widely used inorganic material in window films and glass coatings, known for its excellent near-infrared radiation (NIR) blocking property and high visible light transmittance (T_vis). However, the stability of NIR blocking and the optical properties of CWO in the process of application is an urgent and important problem, because significant changes in optical results can impact the related products, such as window films, glass coatings, and so on. In this paper, the particle sizes and optical properties of CWO are tested to study the light stability and their relative relations. The results indicate that CWO particle sizes between 130 nm and 100 nm (D90, the point where 90% of the particles have a diameter smaller than the specified value) exhibit high stability in terms of NIR blocking and visible light transmittance (Tvis). CWO particles with D90 < 100 nm experience a greater reduction in NIR blocking, though this ability significantly recovers upon exposure to sunlight, making these coatings particularly suitable for use in tropical and subtropical climates.