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The thermal conductivity of non-standard materials for HVAC
Běťák, Karel ; Rubinová, Olga (referee) ; Uher, Pavel (advisor)
The thesis is focused on the determination of the thermal conductivity coefficient on the group of thermoplastics used for 3D printing (PLA, ABS, PETG). The thesis describes the materials used for 3D printing and the design of air conditioning for the grocery store. A stationary method was used for the solution. The heat flux passing through the sample was measured and the thermal conductivity coefficient was calculated. By the chosen method, we determined the coefficient is = 0,11-0,13 W/(m·K). Comparison with the available results of other methods and authors has shown that the resulting coefficient is lower. Based on the data, it is possible to compare the thermal properties of 3D printing materials.
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Impact of injection on mechanical and physical characteristics of mortar
Fridrich, Pavel ; Myslín, Jiří (referee) ; Tomíček,, Oldřich (referee) ; Klečka,, Tomáš (referee) ; Tuza, Karel (advisor)
The increased moisture of the building materials causes the change of its mechanical and physical characteristic. In particular the high amount of loose water in construction shorten the lifetime of the building, is harmful to human beings due to biotic factors and increase the economic expenses of usage of the building. Apart from the costs of rehabilitation the loose water deteriorates the thermal insulative ability (thermal conductivity coefficient ) of perimeter masonry as well. The moisture gets into masonry not only through its deffects but also due to many different reasons. In order to improve the utility value of the buildings we have to deal with the rehabilitation of damp masonry with view to all possible causes. Only the properly working damp proofing ensures the protection against the water leaking from the subfoundation of the building. One of the direct techniques which have undergone rapid progress in last few years is the injection procedure. With use of experimental methods in my dissertation I deal with evaluation of two injection compounds used in Czech Republic and with its impact on the characteristics of the mortar. With the modern hollow bricks (system THERM) it is possible to create horizontal infusion into the lateral mortar grooves in future.
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Influence of the oxide layer on the cooling of steel surfaces
Resl, Ondřej ; Pohanka, Michal (referee) ; Chabičovský, Martin (advisor)
This thesis deals with the influence of the oxide layer on the spray cooling of steel surfaces. As part of the work steel samples with oxide layer are made and the thickness, porosity and surface roughness of this layer are characterized. The average thermal conductivity of porous oxide layer is determined for different regimes of oxidation. Further, the influence of the oxide layer on the heat transfer coefficient during the spray cooling is experimentally investigated on created samples and the basic numerical simulation of the cooling is done for selected experiment with oxide layer. The thesis also contains theoretical introduction to given issue.
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Ultralight concrete with high utility properties
Popelková, Adéla ; Hubertová,, Michala (referee) ; Hela, Rudolf (advisor)
This diploma thesis deals with the technology of production of ultralight concretes using direct lighten cementing compound and at the same time indirect lighten using lightweight aggregate. Further work deals with the choice of suitable raw materials for these concretes. The practical part consists of a proposal of several different recipes, experimental verification and by comparing their properties in a fresh or hardened state.
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The Combustion of Organic Lightweighting Agents in the Chamotte Materials
Smékalová, Veronika ; Keršner, Štěpán (referee) ; Sokolář, Radomír (advisor)
Lightweight chamotte products are popular building material. There are many types of lightweight chamotte on the market, but the most popular lightening options are organic ingredients. This brings some problems to the production of these products. This thesis deals with the burning of various types of lighters from shards of fireclay materials. In the theoretical part are summarized raw materials, which are necessary for production of lightweight chamotte. The results of the published research studies on the topic of lightening of organic lightening products are being described here. The practical part deals with properties of products made of clay or kaolin with the addition of a certain amount of lighter. These added lighters are spruce sawdust, beech sawdust, peat, bran, paper slurry and anthracite. All these lighters are direct. For comparison, the cenospheres, which represent indirect lightweights, were also included in the research. For all specimens, the temperature interval of burnout of specimens, refractoriness, classification temperature, bulk density, thermal conductivity coefficient and other properties were defined.
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Possibilities of utilization of aggregate based on glass powder in new building materials
Novák, Jakub ; Sedlmajer, Martin (referee) ; Zach, Jiří (advisor)
The diploma thesis deals with the use of waste glass powder as an aggregate in thermal insulation plasters for AAC. In the theoretical part, the problem of thermal protection of buildings is discussed first. The production and properties of foamed glass are described. Then the research of plasters, their composition and properties was made. Thermal-insulating plasters are specified and their use has been proposed for thermal insulation of building structures. In the practical part, suitable formulations have been proposed in the form of dry plaster and mortar mixtures (SOMS). Test samples were prepared from them. The physical and mechanical properties were measured. These were compared with the requirements set by standards and technical regulations. To get closer to the behavior of plasters on real buildings an AAC wall was built. The individual recipes were applied on it. It was monitored working with plaster and how it held on the masonry. During ripening crack development was observed. Optimization calculation inculded these aspects and it determined the optimal recipe. All designed recipes can be used as a thermal-insulating plasters.
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Wooden buildings using natural thermal and acoustic insulation
Ambrožová, Elena ; Spáčilová, Jitka (referee) ; Myslín,, Jiří (referee) ; Solař,, Jaroslav (referee) ; Hirš, Jiří (referee) ; Spáčil, Miroslav (advisor)
Dissertation deals with the technical parameters of natural thermal insulation. In addition, there is a global trend in the construction of reducing energy consumption for heating, air conditioning, or with operating facilities in buildings and the use of perspective and efficient building materials with a negligible negative impact on the environment. Therefore, the attention not only professionals are increasingly turning to alternative materials, such as natural insulation, the material can be drawn from local sources and whose production is energy-saving and leaving a small ecological footprint. As part of the doctoral thesis were tested short term water absorption, measurements were made of the thermal conductivity and its change after the test short term water absorption. Was determined dependence of thermal conductivity on humidity and heat resistance was determined. Moreover a natural insulation applications in building construction with a comparison of the various technical parameters and environmental footprint. At the conclusion was made by acoustic insulation in timber construction and price analysis.
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Study efficiency of modern thermal insulations for buildings
Holeček, Dominik ; Skříček, Darek (referee) ; Šťastník, Stanislav (advisor)
The bachelor thesis is partly dedicated to energetic efficiency of buildings and describes possibilities how to evaluate energetic efficiency of buildings in the Czech republic. There is also detailed description of the heat transfer in buildings. We also get to know with production and characteristics of chosen thermal insulators. There are also mentioned methods how to determine thermal insulations characteristics of heat insulations, so called heat conductivity coefficient. The last and the crucial chapter of theoretic part is dedicated to thermo-reflective insulations. There are mentioned some of the basic characteristics of insulations and its material composition as well as usage and methods of thermo-reflective insulations installation in buildings. Practical part is dedicated to description of chosen samples of thermo-reflective insulations and determination of their heat resistance though Hot Box measuring method.
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