A dynamic model of the human/clothing/environment-system.

In this paper a dynamic model of the human/ clothing/environment-system is developed. The human body (controlled system) is subdivided into six segments consisting of the head, trunk, arms, hands, legs and feet. Each segment is further divided into the core, muscle, fat, and skin layer. The afferent signal of the controlling system is composed of the weighted temperatures measured by thermal receptors at sites distributed in the body. The difference between this signal and its threshold activates the thermoregulatory actions: vasomotor changes, metabolic heat production and sweat production. The model considers the competition between skin and muscle blood flow during exercise in hot environments because of limited cardiac capacity, as well as cold induced vasodilatation. Additionally a combined model of heat and mass transfer from the skin through clothing to the environment is developed and incorporated into the thermoregulatory model. The human/clothing model can be used to investigate the interaction between the human body, clothing and environment. The model is validated by comparing the simulation with experimental results under different conditions: heat, cold, exercise, clothing and transient phases. It turns out that the simulation is compatible with the experimental results. We conclude that the model can be applied in a broad range of environmental conditions. Application of the model is easy via a user-friendly interface i.e. a WINDOWS-shell.