Effects of natural ventilation and solar insolation on evaluation of indoor thermal environment in summer and winter seasons

Abstract

In this study we examined ventilation in summer and solar insolation in winter as elements of the indoor environment, with the objective of analyzing the seasonal characteristics of thermal environment evaluation as well as identifying how particular characteristics of space affect the evaluation of the thermal environment. The results were as follows. We found that in summer, feelings of discomfort disappeared even at the high indoor temperature of 33°C when a breeze of at least 0.6 m/s was present. In winter, some subjects expressed a desire for the temperature to be raised while others desired it to be lowered, with a neutral temperature of 23-25°C. We found that subjects' degree of satisfaction to exposure to sunlight was "just right" at temperatures over 25°C, with dissatisfaction at the amount of sunshine being eliminated. During winter, by moving into and out of sunlit areas, subjects created a transient thermal environment in which they actively enjoyed temporary pleasant sensations even in high temperatures.