Solar radiation intensity affects both subjective reactions and physiological functions, especially for people who exercise heavily. Field experiments including a questionnaire survey at various ambient temperatures were performed; outdoor activities under shading (irradiance I = 50 ± 20 W/m²) and non-shading ( I = 700 ± 50 W/m²) conditions during summer in Xi'an were recorded. The results of questionnaires indicated that when the human body reached an extremely hot state, the corresponding environmental temperature was 3.7 °C lower under the non-shading condition, and the range of actual acceptable temperatures was narrower. In terms of thermal sensation, there was a significant difference for people who exercise heavily and those who do not. The results also showed that the curve of fatigue sensation exhibited an inverse Gaussian distribution. Namely, fatigue was promoted under both colder and hotter conditions. Moreover, under non-shading condition, the lowest fatigue incidence was higher, and the corresponding ambient temperature was lower. Changes in objective physiological responses indicated that the solar radiation might cause heat stress. Therefore, when the ambient temperature was higher than 32 °C, physiological stress was higher. Under the same exercise load, the blood pressure was higher under the non-shading condition and systolic blood pressure increased with ambient temperature.

This study aimed to investigate the thermal responses of acclimated workers exposed to heat stress in a real work environment. The physiological indices and subjective thermal perception of the 14 acclimated workers were measured in an industrial plant. The effects of wet bulb globe temperature (WBGT) on physiological indices and subjective thermal perception were studied. The differences in thermal responses between the acclimated workers and unacclimated college students exposed to heat stress were compared and analyzed. The relationship between the mean skin temperature and the thermal sensation was revealed. The results show that the mean skin temperature, oral temperature, and heart rate of the acclimated workers increase with WBGT, while the blood pressure decreases with WBGT. Compared with the unacclimated college students, the acclimated workers felt more comfortable and tolerant under the same heat stress. The thermal neutral mean skin temperature of the acclimated workers is 32.3 °C, which is approximately 1.0 °C lower than that of the unacclimated college students. The results of this study can help ensure the occupational safety and health of heat stress-exposed workers.

It is beneficial for designers to identify the most important design parameters of building envelopes. This study undertook sensitivity analysis integrated with EnergyPlus to assess the impacts of envelope design parameters for naturally ventilated industrial buildings. Sensitivity coefficients of six envelope design parameters for different internal heat intensities were analyzed and compared for buildings in the city of Xi’an, located in the cold climate zone of China. Our results showed that the heat transfer coefficient of the roofs had the most significant impact on indoor temperature. The weights were 32.29%, 33.71% and 30.71%, and the heat intensities were 5, 10 and 15 W/m³, respectively. The effect of the skylight-to-roof ratio was the second most sensitive. The impact of the solar absorptances of the walls and roof on the total number of hours was not sensitive. The results could be helpful for designers to efficiently form alternative design solutions in the design of new and retrofitting industrial buildings.

The aim of this study is to evaluate the cooling effect of a spray fan in an indoor hot environment. An experimental workplace with a thermal environment of high temperature and radiation intensity was set up. The hot environment of the experimental workplace could not meet occupational health requirements when the heat source temperature exceeded 150°C. The effects of air velocity and relative humidity on the natural wet bulb temperature, black globe temperature and wet bulb globe temperature (WBGT) were investigated. The maximum reduction of the WBGT was about 1.7°C, with an air velocity increase by 1 m/s. There was a notable cooling effect on the hot environment for low air velocities (e.g. 0–2 m/s), while the cooling effect only increased slightly for high air velocity (e.g. 2–5 m/s). We also found that the indoor WBGT declined by 0.2–0.8°C when the relative humidity was increased by about 10%. These results may provide guidance for reducing heat stress in industrial hot environment.

Hot working environment not only affects work efficiency, but also poses a potential threat to the physical and mental health of staff. The current common method for dealing with high temperatures is spray-only or ventilation-only. To investigate the impact of different spray and ventilation modes on indoor high-temperature environments, this study examined their effects on indoor environmental parameters, average skin temperature, and psychological indicators. By establishing an experimental platform for high-temperature thermal environments, a spray ventilation cooling system was implemented, and its cooling efficacy in the indoor thermal environment was analyzed. The environmental classification of the high-temperature working environment under experimental conditions is provided based on the experimental data. A comparison and analysis of environmental parameters and physiological and psychological indicators between moderate and high-temperature environments were conducted. The combination of spray and ventilation modes resulted in a 5.3 °C reduction in air temperature, a 24.1% increase in average relative humidity, and a 3.3 °C reduction in average Wet-bulb Globe Temperature (WBGT). The cooling effect was increased by 2.3 °C and the average relative humidity was increased by 10.8% compared to spray-only and ventilation-only modes. In spray and ventilation mode, when the spray volume is increased by 15 mL/min, the air temperature is reduced by 8.2 °C, the average relative humidity is increased by 31.9%, and the average WBGT is reduced by 5.1 °C. This study has guiding significance for finding a reasonable cooling scheme to cope with indoor high-temperature environments.