Center for the Built Environment

A detailed model of heat and moisture transfer through clothing has been developed and implemented in the multi-segment UC Berkeley Thermophysiological Comfort model (BTCM). Equations are presented for two paths of heat and moisture transfer, between naked skin and environment, and clothed skin and environment. Transient behavior due to absorption and desorption by clothing is included. Segment-specific values for clothing insulation, vapor resistance, and the effects of air movement and walking are estimated from various sources. The new model is shown to simulate results from empirical studies with good accuracy. Parametric simulations are done to evaluate the physiological and comfort influences of the airspeed correction equations, and the heat transfer effects of different clothing levels at different temperatures. The results quantify the substantial air velocity and air temperature impacts on thermal physiology and thermal comfort. It can be seen that the new model is useful for studying heat and moisture transfer through clothing, and evaluating thermal comfort in transient environments.