DETERMINATION OF HEAT TRANSFER RESISTANCE OF EXTERNAL WALLS OF BUILDINGS IN NATURAL CONDITIONS

Abstract

Еnergy saving is one of the most important problems of the 21st century. Most of the energy resources in Ukraine are used for heating residential and industrial premises, so reducing energy consumption for heating is relevant and this problem needs to be solved. It can be solved by carrying out a mass reconstruction of existing buildings in order to increase the thermal insulation properties of buildings. For this, it is necessary to conduct a wide audit of them. The existing method consists in determining the heat transfer resistance of the enclosing structure, which is determined based on measuring the air temperature in the room and outside, the temperature of the internal and external surfaces of the structure and the heat flow through it. Such a method requires a lot of time for measurement, complex devices and is not very accurate. The purpose of the work is to develop a method for determining the heat transfer resistance of external walls of buildings in full-scale operating conditions, which would not require measuring the heat flow through the wall and the temperature of its external surface and would significantly simplify the measurement process. The method is based on the fact that the heat transfer resistance of the wall R0 consists of the thermal resistance of the wall and the heat transfer resistances of its inner R2 and outer R3 surfaces, which are connected in series, as a result of which the temperature difference on the specified resistances is proportional to their value q t t RtR���2 3 �02 22�, where q is the heat flux density, t2 and t3 are the indoor and outdoor temperatures, τ2 is the temperature of the inner wall surface. The resistance R0 is determined by building codes R021��where α2 =8.7 W/(m2 K) is the heat transfer coefficient of the inner surface, therefore R t t t02 32 218 7��, � �m2K/W. The method works as follows: measurements are made during the heating period in natural operating conditions of the temperature in the room, the external and internal surface temperatures of the wall. The heat transfer resistance is calculated through the ratio of temperature differences and the known heat transfer coefficient of the internal surface. The proposed method for determining the heat transfer resistance of walls excludes the measurement of heat flow, measurements are made in natural operating conditions.These advantages allow using this method when conducting a thermal audit of building.