Effects of ambient temperature steps on thermal comfort requirements

The purpose of this study was to determine the thermal comfort requirements for steps in temperature. Thirty male subjects were exposed for 50 min to a 34 or 37°C condition, and then quickly transferred to a cooler environment of 31, 28, 25, and 22°C for 50 min. Mean skin temperature was continuously measured, and the subjects reported their thermal sensation and comfort sensation every 2 min. Just after the step changes, the mean skin temperature immediately decreased, while the thermal sensation overshot and gradually rose again. Both the skin temperature and the thermal sensation seemed to reach a constant level within about 20 min. However, there were differences in the mean skin temperature and the neutral temperature derived from the correlation between the ambient temperature and the thermal sensation even 50 min after the steps, due to the thermal environmental condition before the changes of temperature. The change in the neutral temperature with time was expressed as two attenuating equations. These equations indicate that there is an obvious difference between the neutral temperatures due to the thermal condition before step changes, and that it takes >50 min after the step changes to reach the steady state. It is expected that these equations predict in quantitative terms the thermal comfort requirements within a given experimental condition.

[1]  Tetsumi Horikoshi,et al.  CONFIGURATION FACTORS BETWEEN A RECTANGULAR SOLID AS A MODEL OF THE HUMAN BODY AND RECTANGULAR PLANES, FOR EVALUATION OF THE INFLUENCE OF THERMAL RADIATION ON THE HUMAN BODY : II. CHARACTERISTICS OF CONFIGURATION FACTORS FOR THE RECTANGULAR SOLIDS , 1977 .

[2]  S. Takada.  Thermophysiological response of human body in non-steady state considering influence of transfer and storage of heat and moisture in and around clothing , 2001 .

[3]  James D. Hardy,et al.  The technic of measuring radiation and convection , 1938 .

[4]  Hiroaki Tanaka,et al.  EXPERIMENTAL STUDY ON THERMAL SENSATION INDEX IN THERMAL TRANSIENTS , 2003 .

[5]  Standard Ashrae.  Thermal Environmental Conditions for Human Occupancy , 1992 .

[6]  P. Fanger,et al.  Thermal Sensations Resulting From Sudden Ambient Temperature Changes , 1993 .

[7]  A. P. Gagge,et al.  An Effective Temperature Scale Based on a Simple Model of Human Physiological Regulatiry Response , 1972 .

[8]  Tetsumi Horikoshi,et al.  Responses of human skin temperature and thermal sensation to step change of air temperature , 1993 .

[9]  Naoki Kawakami,et al.  Experimental Study on Thermophysiological Response of Clothed Subjects Exposed to Thermal Transients – Sweating and Evaporation Process – , 1999 .

[10]  P. O. Fanger,et al.  Thermal comfort: analysis and applications in environmental engineering, , 1972 .

[11]  O. Kobayashi,et al.  The body surface area of the normal Japanese children. , 1952 .

[12]  J D Hardy,et al.  Comfort and thermal sensations and associated physiological responses at various ambient temperatures. , 1967, Environmental research.

[13]  R. Dear,et al.  Temperature Transients: A Model for Heat Diffusion through the Skin, Thermoreceptor Response and Thermal Sensation , 1991 .

[14]  P. Fanger.  Moderate Thermal Environments Determination of the PMV and PPD Indices and Specification of the Conditions for Thermal Comfort , 1984 .