DETERMINATION OF THE HEAT TRANSFER COEFFICIENT OF THE WALL OF A MULTI-STOREY RESIDENTIAL BUILDING BY THE THERMOMETRIC METHOD

Abstract

During thermal modernization of existing buildings and assessment of energy parameters of new housing, there is a need for experimental in-kind determination of the heat transfer coefficient (heat transfer resistance). In our opinion, the optimal method for determining it is the thermometric method (THM). Its equipment is cheaper, the sensors do not disturb the measured heat flow, and temperature measurement is affected by fewer factors than when using a thermal imager. The thermometric method is not standardized, but along with this, it is widely used to measure the heat transfer coefficient during energy audits, in commercial devices. During the research, experimental in-kind measurements were carried out over certain periods of the temperatures of the internal environment, external environment, and internal wall surface. Before taking measurements, the internal wall surface was examined with a thermal imager to select an area with minimal impact of heat-conducting inclusions. The wall surface temperature in the room was measured by three type K thermocouples placed at a distance of approximately 15 cm from each other and recorded by a recorder at a specified interval. The thermocouples were placed so that they were not on the same horizontal or vertical line. Average temperature values ​​were entered into the calculation. The temperature of the environment inside the room was measured by a temperature recorder, which was placed at a distance of approximately 30 cm from the wall surface at a height of 1.5 m, the same as the height of the thermocouples on the surface. The temperature of the outside environment is recorded by a logger. Thermologgers recorded the temperature of the air environment at a given interval. Using the temperatures measured at a given interval, the heat transfer coefficient of the wall of a residential building was calculated using the thermometric method (THM). The heat transfer coefficient of the inner surface of the wall is adopted according to DSTU. An analysis of the influence of various factors, in particular measurement intervals, on the value of the heat transfer coefficient was performed.