Local clothing properties for thermo-physiological modelling: Comparison of methods and body positions

Abstract

Thermo-physiological modelling has become a frequently used and valuable tool for simulations of thermoregulatory responses in a variety of applications, such as building and vehicular comfort studies. To achieve reliable results, it is necessary to provide precise inputs, such as clothing thermal parameters. These values are usually presented in a standing body position and scarcely reported locally for individual body parts. Moreover, as an air gap distribution is both highly affected by a given body position and critical for clothing insulation, this needs to be taken into account. Therefore, the aim of this study was to examine eight probable approaches to assess the clothing parameters using state-of-the-art measurements, analytical and empirical models, and estimation. Next, we studied the effects of the eight clothing inputs on predicted thermo-physiological response under the same environmental conditions conducted with the Fiala model. Secondly, the study focuses on differences between seated and standing positions, both using two clothing sets representing typical European, indoor, summer and winter ensembles. The results show clear differences in clothing thermal properties between sitting and standing positions on both lower limbs and torso. The outputs of the eight examined methods showed discrepancies between them, in the range of up to 200%. The discrepancies from the eight clothing inputs were also propagated in the results of thermo-physiological responses. These varied significantly in terms of their impact on predicted thermal sensation, highlighting the importance of using adequate inputs for modelling.