Revision and Optimization of the Wissler Thermal Model – Assessment, Analyzation, and Rework of the Passive Model

The Virtual Habitat project (V-HAB) at the Technical University of Munich (TUM) aims to develop a dynamic simulation environment for life support systems (LSS). Within V-HAB a dynamic human model interacts with the LSS by relevant metabolic inputs and outputs based on internal, environmental and operational factors. The human model is separated into five sub-models (called layers) representing metabolism, respiration, thermoregulation, water balance and digestion. The Wissler Thermal Model was converted in 2015/16 from Fortran to C#, introducing a more modularized structure and standalone graphical user interface (GUI). An interface was implemented to allow the usage of the standalone Wissler Thermal Model with V-HAB and any other programming environment offering a MySQL connection. While previous effort was conducted in order to make the model in its current accepted version available in V-HAB, present work is focusing on the passive system. The passive modelling, including the modelling of the human body, the modelling of the heat transport mechanisms, and the numerical calculations and procedures performing the calculations, was assessed, analysed, and reworked. The rework includes a more precise analyzation of the real human (tissue composition and body measurements) build-up using state-of-the-art data. The current work focusses on the optimization of the predictions of the integrated Wissler Thermal Model (consisting of passive and active model). The models (old and reworked version) are subsequently compared to one another and to experimental data.