Effects of step changes of temperature and humidity on human responses of people in hot-humid area of China.

An experimental study of human responses to step changes of temperature and humidity was carried out on people in hot-humid area of China. Thirty college students who were naturally acclimatized to local climate and well experienced with air-conditioned environments participated in the experiment. Their physiological and psychological responses were measured continuously under conditions of neutral-warm and neutral-cool. Psychological lead occurs in all conditions expressed as psychological responses reaching steady state in a much shorter time than physiological ones, and overshoot occurs under sudden heating and does not occur under sudden cooling. Validation test of the Two-Node model shows that the model overestimates the steady state skin temperature under conditions of 20, 23 and 29 °C, and underestimates the change rate of skin temperature at the initial time of step changes. Heat acclimatization is suggested to be taken into account while applying the Two-Node model in hot-humid area of China. Relationships between physiological and psychological responses under step changes of neutral-warm and neutral-cool are established, indicating that both skin temperature and its change rate over time have significant impacts on thermal sensation. The acceptable conditions for transitional spaces in hot-humid area of China are recommended as the upper limits of air temperature 29.2 °C at 50% RH and 28.0 °C at 70% RH for 90% percentage satisfied, and 31.0 °C at 50% RH and 29.5 °C at 70% RH for 73% percentage satisfied. [ABSTRACT FROM AUTHOR]