FIELD: measuring; construction.
SUBSTANCE: invention relates to construction physics, namely to obtaining characteristics of heat transfer resistance of external enclosing structures of buildings in full-scale conditions when a stationary heat transfer mode is achieved. Disclosed is a method for determining resistance to heat transfer of a building wall, using the measured values of temperatures outside and inside the building, on its outer and inner surfaces of the investigated section of the building wall and the surface density of the heat flow passing through the building wall, in which on opposite surfaces of the building wall two insulated U-shaped boxes are fixed symmetrically relative to each other, in each of which a heater and sensors of air temperature and temperature of the surface of the inner and outer surfaces of the building wall are placed. At the same time in the inner box on the building wall the sensor of surface density of heat flow is placed, and the open cavity of the boxes is sealed from the building wall. Sensors installed outside and inside the boxes are switched on and recording of their readings is started. Using the heaters inside the boxes, the temperature is set to 5 °C is higher than the temperature outside and inside the building, respectively, at the beginning of the experiment and is maintained until a stationary heat transfer mode is established in the wall of the building. After establishing a stationary heat transfer mode in the building wall, according to the readings of sensors installed inside the boxes, the experimental heat transfer resistance of the building wall is determined by the formula:
where to.s is the temperature of the outer surface of the building wall, °C; ti.s. is the temperature of the inner surface of the wall of the building, °C; q is surface density of heat flow, W/m2. Then, the building wall heat transfer resistance is determined by adding the measured experimentally determined heat transfer resistance of the building wall to the standard values of heat release resistance of the inner and outer surfaces of the building wall:
where αi is the heat transfer coefficient between the internal air and the inner surface of the building wall, 8.7 W/(m⋅°C); αo is the heat transfer coefficient between the outside air and the outer surface of the building wall, 23 W/(m⋅°C); Rexp is experimentally determined resistance to heat transfer, m2/(W⋅°C).
EFFECT: improving accuracy of obtained characteristics of resistance to heat transfer of building envelopes.
1 cl, 1 dwg
