A Two - Dimensional Model for Calculating Heat 1 Transfer in the Human Body in a Transient and Non - 2 Uniform Thermal Environment

13 A thermal model for the human body is used to assess the temperature of the body and 14 a person’s thermal comfort level. Most models available in the literature were 15 developed for a uniform thermal environment and have limited applications. This study 16 developed a 12-segment model for transient and non-uniform surrounding conditions 17 by considering two-dimensional heat transfer in each segment of a human body. This 18 heat transfer included convection, radiation, and evaporation on bare skin and skin 19 covered with clothing. The model allows non-uniform clothing insulation across 20 different body segments. The heat transfer between two body segments was estimated 21 from blood circulation through counter-current heat exchange. This study evaluated the 22 model’s performance for subjects with and without clothing under a wide range of 23 transient and non-uniform thermal environmental conditions. Good agreement was 24 observed between the measured and calculated skin and rectal temperatures, although 25 there were small discrepancies. The two-dimensional model developed in this study is 26 a step forward in predicting thermal comfort under transient and non-uniform 27 environmental conditions. 28