Measurements and Predictions of the Skin Temperature of Human 1 Subjects in Outdoor Environments

11 Thermal comfort in outdoor spaces is strongly associated with the quality of social life 12 in an urban community. This study investigated dynamic outdoor thermal comfort under 13 cold, mild, and hot climatic conditions with air temperature ranging from -0.1 to 35.0 oC. 14 Using a total of 26 human subjects in 94 tests under these climatic conditions, this study 15 measured outdoor thermal environmental parameters, monitored subjects’ skin 16 temperature, and recorded subjects’ thermal sensation. The study found that fluctuations in 17 wind speed and solar radiation led to changes in convective and radiative thermal loads on 18 the human subjects. Their skin temperature and thermal sensation changed accordingly. In 19 the cold conditions, the skin temperature of the trunk was stable at around 34 oC, while the 20 skin temperature of the face decreased to 19 oC. This investigation developed a human heat 21 transfer model that considers outdoor radiative heat exchange and transient heat transfer in 22 clothing. The mean skin temperatures predicted by the model agree reasonably well with 23 the measured data. However, the discrepancy between the predicted and measured local 24 skin temperature under extremely cold conditions can be as large as 6 K. 25