Experimental studies of heat gain into building premises through wooden building envelopes in summer

Experimental studies were carried out to measure heat input into the premises of buildings with wooden envelops in the summer. Two types of wooden building envelopes were studied: solid wood (log frame) and a wall insulated with mineral wool based on a wooden frame with a ventilated facade made of metal siding. The structures differ in thermal inertia and the magnitude of thermal resistance. As a result of the research, it was established that in the summer, for a solid wood constraction, the maximums and minimums of the heat flux density into the room are shifted relative to the maximums and minimums of temperature fluctuations on the external surface for a time of about 6.5 hours. Maximum heating of the room occurs in the evening around 9–10 pm. The minimum air temperature is reached around 9–10 am. For a frame wall, the shift in the maximum and minimum heat flux density is about 2 hours, which is due to the much lower thermal inertia of such a structure. The measured daily fluctuations in inner air temperature are at the level of 2^оС, while for a room with a solid wood wall can reach 5^оС, which is associated with the higher heat-insulating properties of the frame wall. The characteristic values of the density of heat flows entering the premises were: 2.0 W/m² for a solid wood wall and -0.2 W/m² for a frame wall.