An improved thermal model of the human body

The goal of this study is to develop a more realistic human thermal model. Previous models have been based on simple cylindrical geometries. The current study uses shaped and refined body segments to simulate heat and mass transfer in the human body during a transient process. The body segments and blood vessels (or respiratory tract) were discretized into 3-D and 1-D elements, respectively. Criteria were developed to simulate the circulatory system, respiratory system, and human thermal responses. The finite element method was employed to solve the mass and energy equations which were written for each element. The body model was compared against actual data available in literatures: cold, neutral, and warm conditions, with ambient temperatures of 15°C (59°F), 25°C (77°F), and 35°C (95°F). For steady state simulation, the results showed that the skin temperatures of head, trunk, and limbs matched the experimental data very well for all three conditions, while the neck and limb extremities (hand and foot) showed some difference, especially for the cold condition. In transient process, our simulation gives good predictions for warm and neutral conditions, but 1–2°C difference in skin for cold condition. The comparison of cylindrical-based model, our current model, and experimental data shows that our model is able to give more accurate prediction of human body temperatures than previous models.