The use of novel thermal-efficient building materials and technologies that allow increasing the level of thermal protection of external envelope structures and reducing the time for construction are of practical interest and represent a relevant task in the conditions of rapidly changing and increasing requirements to energy efficiency of buildings. This research aims at simulating the process of spatial heat transfer in a multilayer non-uniform structure of an external cast-in-place framed wall produced from polystyrene concrete with a stay-in-place formwork. Based on the physico-mathematical model developed with the use of ANSYS and COMSOL software complexes, parametric analysis of the impact of various factors on thermal behavior of the external wall was performed with the account of heat-stressed frame elements. The nature of temperature fields distribution in a polystyrene concrete structure was defined, and its thermal protection properties were investigated. The impact of a metal frame on thermal protection properties of a wall was found to be insignificant.

Abstract. The purpose of this paper is numerical study on the impact of location of cylindrical fillers made of insulating material on the thermal state and thermal protection properties of the corner fragment of cast-in-place lightweight aggregate external wall. Solution of spatial thermal conductivity problem was obtained and the effect of low-thermal-conductivity fillers location inside the corner fragment of a wall was analyzed using the software complex Ansys. The nature of temperature fields distribution was determined both inside the wall and in the inner corner of the structure. The method for temperature increase in the inner corner is suggested and its quantitative evaluation is performed. The effect of thermophysical and geometrical parameters of wall materials on its thermal insulation properties is analyzed.

The regularities of formation of temperature fields in a plane three-layer system with a not-through cross connection (connector) are considered with boundary conditions of the second kind on one exterior surface of the system. The character of distribution of the temperature fields in the zone of influence of the steel connector is investigated experimentally. The results of the experiment are compared to the numerical solution of the problem with boundary conditions of the second and third kind on the interior surface of the wall. Their satisfactory agreement is shown.The regularities of heat transfer in a plane three-layer system with a not-through heat-conducting connection (connector) have been investigated theoretically in [1]. To extend this investigation it became necessary to solve the problem of heat conduction in a plane three-layer system with a not-through cross connection in the case of boundary conditions of the second kind on one exterior surface of the system for optimum designing of energy-saving enclosing structures of buildings and development of systems of their external thermal protection (warmth-keeping).The present work seeks to develop an efficient numerical method of solution of the problem, which is rapidly adaptable to different configurations of multilayer external enclosures with cross connections, to compare results of numerical solution of the problem of heat transfer in a three-layer exterior wall with a connector in the case of boundary conditions of the second and third kind on its interior surface, to experimentally investigate the character of distribution of temperature fields in the zone of influence of a steel connector, and to compare the results of numerical solution to experimental data.Physicomathematical Formulation and Method of Solution of the Problem. Heat transfer through a plane multilayer system with a cross connection will be considered using a brick three-layer exterior wall with a cylindrical connector as an example (Fig. 1). The internal and external layers of the enclosure represent the brickwork and the central layer is a warmth-keeping jacket. The ends of the connector are embedded in the internal and external layers of the enclosure. The geometric dimensions of the layers of the enclosure and the connector are prescribed. The thermophysical characteristics of the wall material (λ i , ρ i , and c i , i = 1, 4 ___ ), which are generally dependent on temperature, are known. The temperature of the medium t g,e and the heat-transfer coefficient α w are prescribed on the exterior surface of the enclosure, and the heat-flux density q 0 is prescribed on the interior surface. The temperature profile over the enclosure thickness t 0 , t 12 , t 23 , and t w outside the zone of influence of the connector is determined from the known value of q 0 from the analytical solution of a one-dimensional stationary heat-conduction problem [2].We will solve the problem formulated in a cylindrical coordinate system (Fig. 1). The origin of coordinates will be located on the inte...

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The purpose of this paper is numerical study on the impact of location of cylindrical fillers made of insulating material on the thermal state and thermal protection properties of the corner fragment of cast-in-place lightweight aggregate external wall. Solution of spatial thermal conductivity problem was obtained and the effect of low-thermal-conductivity fillers location inside the corner fragment of a wall was analyzed using the software complex Ansys. The nature of temperature fields distribution was determined both inside the wall and in the inner corner of the structure. The method for temperature increase in the inner corner is suggested and its quantitative evaluation is performed. The effect of thermophysical and geometrical parameters of wall materials on its thermal insulation properties is analyzed.