Seasonal Differences of Psychological and Physiological Responses in Tropical Urban Climate

Abstract

This research aims to use the outdoor thermal environment evaluation index ETFe to quantify effects on the thermal sense of the human body of a tropical region climate with small annual temperature differences, and to examine seasonal differences in the thermal sense. Given that the average temperature of the earth is forecasted to rise, studying the effects on the human body from outdoor thermal environments in tropical regions is important for considering how to spend time outdoors in the future. This study clarifies seasonal differences in effects on the human body by comparing the effects on the thermal sensations of the human body from outdoor thermal environments in the winter and the dry season of Bangkok, Thailand in the tropics. The mobile measurements were carried out on the campus of Chulalongkorn University, Bangkok, Thailand. The subjects reported the thermal sensation and the thermal comfort that they experienced while exposed at the observation point. Air temperature, humidity, air velocity, short-wave solar radiation, long-wave thermal radiation, ground surface temperature, sky factor and the ratio of green and water surface solid angles were measured. We found no large seasonal difference between the winter and the dry season in skin temperature due to body temperature regulation. It is clear that in the winter season, people prefer a lower temperature than in the dry season, and in the dry season they tolerate higher temperatures than in winter. The effect of the seasonal difference appears in the amount of change to thermal sensation. We found that it is difficult for seasonal differences to greatly affect the amount of change to thermal comfort. We found that the effect of seasonal difference is that people show stronger responses to thermal comfort for thermal sensation 897in winter than in the dry season.

Thermal Manikin of Infant

“…Kurazumi et al [5] [6] [7] qualitatively clarified the effect that strong short wavelength solar radiation in tropical climates has on the thermal sensation of the human body when applying the outside thermal environment evaluation index ETFe [2]. It clarifies that in tropical areas where the effects of nighttime cooling cannot be expected, the effect of long-wave length thermal radiation is strong in the shade of objects made of materials with high heat capacity, and the effect of improving the thermal sensation of the human body through shade is low.…”

Skin Temperature and Body Surface Section in Non-Uniform and Asymmetric Outdoor Thermal Environment

“…Although it is possible to make calculations using a human shaped model [90], since there is little refer-ence material on contact points on the body for numerical thermal manikin and human body measurements have not been made, the validity of these cannot be verified. Also, the large effects of long-wavelength thermal radiation in outside environments have been confirmed from measurements made by Kurazumi et al [25] [26] [27]. Therefore, the previously mentioned radiant heat transfer area factor from each body part (effective radiation area factor) is a problem.…”

“…In evaluating the outdoor environment, the psychological reaction of the human body is made the focus, and research quantitatively dealing with the heat balance of the human body is rare. The only studies that quantitatively investigate the influence on the human body using comprehensive thermal environment evaluation indices based on the heat balance of the outdoor environment as the axis of evaluation are those by Kurazumi et al [20]- [27].…”

“…These may contribute as a local effect on the human body, even if the heat balance in the whole human body is the same. As pointed out by Kurazumi et al [24] [26] [27], the influence of these environ- and so this experience can be thought to induce the condition of relative comfort. Accordingly, changes with an effect that mitigates thermal function are considered to be variables for discomfort with regard to other environmental factors also.…”

Thermal environment mitigation effects in suburban area

“…Kurazumi et al [4][5][6] demonstrates the influence of an outdoor thermal environment on the human body with the outdoor thermal environment evaluation index ETFe [7] for the influence of a tropical climate with strong shortwave length solar radiation on the thermal sensation of the human body as the evaluation axis. It clarifies that in tropical areas where the effects of nighttime cooling cannot be expected, the effect of long-wave length thermal radiation is strong in the shade of objects made of materials with high heat capacity, and the effect of improving the thermal sensation of the human body through shade is low.…”