Analysis on living environment of heat insulation and air-tight houses utilizing hygrothermal property of red pine plank

Abstract

Due to the enforcement of the "Energy Conservation Standard for Housing" and the "Housing Performance Indication Law" in Japan, insulation and air-tightness have been all the more emphasized and have drastically advanced. However the factors significantly interconnected to the comfort such as indoor humidity variation arisen from human living with moisture sorption and desorption of walls have been disregarded. In this paper, red pine plank is utilized as the interior finishing material with moisture sorption and desorption characteristics to provide the function with constant temperature and humidity to insulation and air-tight houses. The model experiments in reference to temperature and humidity response method, the actual measurement of hygrothermal environment of houses, and the numerical simulation have examined the influence of the red pine plank on the indoor environment. The simulation software "THERB" which has complete HAM features (heat and moisture transfer and airflow) including principles of moisture transfer within walls is used and its accuracy is also verified through the comparison of the calculations and the experiments. As the results, the effects of the red pine plank to prevent humidity increase in rainy season and over dryness during heating are clarified. Then constant temperature capability caused by thermal storage within the red pine plank is also demonstrated.