The dynamic development of the automotive industry and improvements in quality of life have caused a significant increase in the production of car tires. Unfortunately, when the useful life of these products comes to an end, the problem of their disposal arises. The article presents the results of tests of epoxy mortars in which granules made from waste tires were used as a substitute for sand in the amount of 0, 20, 40, 60, 80 and 100% vol. respectively. The available literature lacks information about resin composites that arise with such a large or complete replacement of sand with rubber waste. Along with the increase in the content of waste, the values of strength parameters of composites decreased; however, a material characterized by very low water absorption, that is lightweight and with a low thermal conduction coefficient was obtained. Using the ADINA program, numerical simulations were carried out regarding the temperature distribution in a part of the building structure containing modified rubber mortar. The results of the simulation confirmed the possibility of practical use of the obtained composite due to its good thermal insulation properties. This approach to testing composites modified with rubber waste is innovative.
The article presents a comparative analysis carried out using three methods, determining the heat transfer coefficient U for a ceramic product modified with a phase change material (PCM). The purpose of the article is to determine the convergence of the resulting thermal characteristics, obtained using the experimental method, numerical simulation, and standard calculation method according to the requirements of PN-EN ISO 6946. The heat transfer coefficient is one of the basic parameters characterizing the thermal insulation of a building partition. Most often, for the thermal characteristics of the partition, we obtain from the manufacturer the value of the thermal conductivity coefficient λ for individual homogeneous materials or the heat transfer coefficient U for the finished (prefabricated) partition. In the case of a designed composite element modified with a phase change material or other material, it is not possible to obtain direct information on the above parameter. In such a case, one of the methods presented in this article should be used to determine the U factor. The U factor in all analyses was determined in stationary conditions. Research has shown a significant convergence of the resulting value of the heat transfer coefficient obtained by the assumed methods. Thanks to obtaining similar values, it is possible to continue tests of thermal characteristics of partitions by means of numerical simulation, limiting the number of experimental tests (due to the longer test time required) in assumed different partition configurations, in stationary and dynamic conditions.
The article presents four equivalent methods for checking mold growth on the surface of building barriers and checking water vapor condensation on their surface. Each method applies to two parallel phenomena that may occur on a building barrier. The first method is to calculate and compare temperature factors. In the second method, the characteristic humidity in the room is calculated and compared. The third method is to calculate and compare the characteristic temperatures in the room. The fourth method is based on the calculation and comparison of characteristic water vapor pressures. Three boundary conditions are presented for each method and phenomenon: when a given phenomenon can occur, when it begins or ends, and when it does not occur. The presented methods systematize the approach to the problem of mold development and surface condensation. The presented calculation results relate to the selected building barrier functioning in specific indoor and outdoor climate conditions. The calculation results confirm the compliance of the presented methods in identifying the phenomenon of mold growth or condensation on the surface of the barrier. A graphical interpretation of the results for each method with periods of occurrence or absence of a given phenomenon is also presented.
The article presents the results of tests of the thermal operation of a transparent barrier, which is equipped with an external thermal insulation roller blind. The tests were carried out under real climatic conditions. The barrier in question was mounted on the south façade in two external test chambers. The aim of the research was to determine whether and to what extent the external thermal insulation roller blind influences the flow of heat through the transparent barrier. The second goal was to propose a way of programming the position of the blind so that it would be beneficial in both limiting of overheating in the adjacent room during the high summer sunshine and minimizing the need to reheat the room in the case of high clouds and low temperatures in the outside air. During the tests, the following values were measured: the intensity of solar radiation, temperature (outside air, indoor air and the internal surface of the barrier), as well as the heat flux density on the internal surface of the barrier. The test results indicate that the use of an external thermal insulation roller blind has a significant impact on the thermal operation of the transparent barrier and thermal comfort in the room adjacent to the barrier. The method of programming of the position of the blind should take into account both the temperature of the outside air and the value of the intensity of solar radiation, as well as the temperature of the air in the room adjacent to the barrier, and the direction and values of the heat flux passing through this barrier.
The article presents an analysis of temperature on an internal wall surface. Simulations on the external wall corner were also carried out. It is a place where the surface temperature is lower due to the thermal bridge effect. The calculations were performed with the ADINA program used for numerical simulations on heat transfer through divisional structures. Finite element analysis was employed to solve the task. The calculations were performed for five case studies with different corner structures and different methods of insulation. The baseline was a wall with the heat transfer coefficient U = 0,30 W/(m2K). The reason for selecting such a coefficient for analysis was due to the fact that in most Polish buildings thermal resistance of walls results from technical norms from before January 2014. The findings of the numerical simulations were used to determine the maximum relative humidity of the internal air where water vapour condensation may occur on the internal surface of the corner. The calculations were crucial to making a qualitative assessment of the employed solutions. The findings showed that it is possible to improve the thermal functioning of a wall in the corner thanks to an additional layer of thermal insulation, for example in the form of an avant-corps, placed within the corner.
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