To design a residential or commercial building with high energy performance that would be economical at the same time, an analysis was performed that relates these two aspects of the problem. The first aspect is focused on evaluation of the thermal performance of a multi-layered wall in order to achieve the lowest energy consumption for heating and cooling. The second aspect of the analysis covered the choice of materials (type, thickness and price) so that the building has the lowest possible construction costs, but the best achieved thermal comfort. The three types of external walls with the same structure were analyzed in this paper. The lowest and highest values of the layer thickness offered by the manufacturer were chosen and their dynamic characteristics for the heat transfer were calculated. The following step was to perform optimization of the objective function, which was defined by the unit price of the material per mass of the material, that is, the economical aspect was provided. The genetic algorithm method was used to obtain the optimal thickness of the external wall layers that provided the best dynamic characteristics for the heat transfer in the defined conditions.

The analysis of influence of factors that depend on construction characteristics of the vibrosieves with circular vibrations on screening efficiency is presented in this paper. The dependence of the screening efficiency on the aperture size, length and inclination of the screen, as well as on vibration amplitude, is considered. Based on obtained results, one can see that the screening efficiency increases with vibration amplitude and the screen length increase. Further, increases of the screen inclination and aperture size are causing an initial increase of the screening efficiency, which is later decreasing.

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In this paper, analysis of dynamic thermal performance of multilayer insulation wall in residential buildings in Serbia is performed. Considering that the final goal is to build a residential structure with the highest level of efficiency, that is, with the lowest energy consumption for heating and cooling, it is necessary to determine good thermal characteristics of a multilayer wall. The first type of walls, which were analyzed had the same structure with different thicknesses of individual layers. The second type of analyzed walls had the same structure, but the thermo-insulating layers occupied different positions. The third type of walls had different structures, but the same total thickness. Based on the results presented in the paper, it can be concluded that in walls with similar structures, the same total thickness and different thicknesses of individual layers, there are differences in the external temperature variation shift. The position of the thermal insulation layer for the same wall structure does not significantly affect the change in temperature oscillation caused by the change in the outside temperature. Changing the wall structure, however, has significant influence on the thermal capacity. This analysis offers the possibility to choose the optimal solution for the wall structure with the highest energy efficiency.

AbstractThermal fracture characteristics – the thermal energy release rate and thermal stress intensity factor of a semi-infinite crack at an interface between the two elastic isotropic materials, subjected to the temperature variations, are considered in this paper. Those characteristics are determined based on application of the linear elastic fracture mechanics (LEFM) concept. Expressions for obtained theoretical solutions are compared to solutions from literature and they are found to be more concise. Influence of the materials change on these two thermal fracture properties were observed, as well as the influence of the thickness ratio of the two layers constituting the interface.