This master thesis deals with problematic of the heat convection in phase change materials (PCM) and PCM with nanoparticles. The derivation of stationary and non-stationary equations for 1D, 2D and 3D heat convection are described in detail. The finite element volume method is used for solution to these equations, of which principle is described carefully. The aim of this thesis is model development for 2D solution to temperature distribution at heat convection in PCM and influence assessment of nanoparticle implementation into material on given temperature distribution. Software MATLAB was used for model development, solution and plotting graphs.

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The Phase change materials (PCM) have the ability to absorb and release heat as the temperature changes from high to low temperature and vice versa. The use of phase change materials has increased in the construction sector due to the established environmental requirements and the various application benefits, especially in the thermal comfort of building applications and construction of sustainable infrastructure around the world (Berardi and Gallardo, 2019). Over the past decade, many studies have been conducted on the thermal properties of PCM (phase change material), however, few studies have focused on the study effect of PCM on mechanical and physical properties, although of great importance. In this work, three different microencapsulated types of phase change material (PCM) have been studied, while its effect on the mechanical and hydration properties of the cement paste with regard to constant ratio of water to cement ratio has been taken into account. The PCMs that have been studied are the following: Microencapsulated PCM, which is Nextek 24 D, Nextek 57D (Microtek Laboratories) and Croda Therm ME29P (Croda). In this study, various tests were performed on cementitious paste mixed with different doses of PCM to test the effect that PCM has on the cement hydration (under semi-adiabatic and isothermal conditions), the physical properties (setting time, slump flow, density) and the mechanical properties ( compressive strength). The results of this study indicated that both the melting point of the PCM and its amount have a decisive effect on the properties of the cement paste. Finally, the following conclusions have been drawn: • Additions of different dosage levels of the 24D and Croda PCM types showed that an increase in the dosage resulted in impaired mechanical and physical properties such as compressive strength of the cement paste (mechanical) decreased, and the density and random flow decreased (physical). While Nextek 57D did not show a great effect on cement paste according to density and random flow, which gives reduced negative impact on cement paste workability (physical). According to the mechanical properties, Nextek57D PCM with different levels of levels showed immediate positive effect on cement paste compressive strength compared to reference paste (no addition of PCM), and other cement pastes with other PCM types used in this study. • Mikrotek 57D PCM also gives a positive effect at different dose levels compared to two other types of Nextek 24D and Croda PCM regarding the effect of heat flow, which gives rise to hydration heat during the cement hydration process. However, other types of Nextek 24D and Croda in all quantities showed negligible effect on the heat flow during the cement hydration process.

The work is focused on the development of an environmentally friendly external thermal insulation composite system in terms of product composition and composition of the whole system. The intention is to develop an alternative to standard external thermal insulation composite systems. Undoubtely, standard systems have a contribution to energy savings (primary role), but their actual production and composition is also a burden on the environment. The research is focused onthe development of adhesive and leveling substance and plaster using progressive material with phase transformation and energy by-product (fly ash). Furthermore, it is focused on the selection of insulation from renewable sources. Therefore, there is paid attention to the overall composition of the thermal insulation system in order to achieve the most effective impact with respect to the environment. The goal is to achieve secondary energy and resource savings due to the composition of components and also the composition of the entire system.