Abstract
Human thermal comfort largely depends on the thermal physiological state formed through heat transfer between the human and the surrounding environment. Therefore, it is important to clarify the characteristics of heat transfer distribution of the human body as well as those of skin temperature distribution for evaluating non-uniform thermal environments. Heat flow sensors and thermal manikins have been used to measure local heat losses of the human body. However, due to the complexity of the human body shape, heat flow sensors present difficulties when selecting where or how to attach them to the skin in order to obtain accurate repeatable data. With regard to the thermal manikin's measurement, as the local heat loss is dependent on the relationship between the thermal environment including the clothing and local skin temperature which was set on the surface of the thermal manikin, the skin temperature setting for the thermal manikin is very important. We proposed a measurement method of heat flow by use of the thermal manikin in the setting of the experiment. Generally thermal manikins have been used to measure skin temperature at constant heat flow, heat flow at the constant skin temperature or both heat flow and skin temperature by use of the comfort mode on the physical characteristics of the manikin. As we had already measured local skin temperatures for the human subjects in the first session of this study, the surface temperature of the thermal manikin was set at the same skin temperature for the local area, and the local heat flow was measured with the manikin in the same environmental conditions in the thermal booth in the climatic chamber. From the experiments. the following conclusions were obtained; 1) Local dry (sensible) heat loss changed depending on the environmental thermal non-uniformity, even if overall mean dry heat loss was kept at almost constant value. 2) Overall average dry heat loss is not always a sufficient index to express thermal comfort in a non-uniform thermal environment. It is essential to consider other factors like local sensible heat loss, mean skin temperature, local skin temperature, etc. along with the overall average dry heat loss. 3) Sensation of hot and discomfort in the forehead changed in accordance with both changes in local skin temperature and local dry heat loss. However, sensation of cold and discomfort in the dorsum of the foot changed depending on a single parameter only i.e., local skin temperature.
