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SELECTIVE EMITOR FOR THERMOPHOTOVOLTAIC SYSTEMS
Šimonová, Lucie ; Hrzina,, Pavel (referee) ; Šály,, Vladimír (referee) ; Vaněk, Jiří (advisor)
The work is focused on research and development of a suitable method for creating a selective emitter for the visible and near infrared region so that they are able to work optimally together with silicon photovoltaic cells in a thermophotovoltaic system. The aim of the work was to develop a new method of creating very fine structures outside the current standard, which will increase the emissivity of the base material to meet the needs of a selective emitter for the VID and NIR region. The methods available to us for the creation of structures were chosen, from which we eliminated all unsuitable ones and we introduced the optimal procedure and parameters for their creation for the selected method. In this work, we focused on both ceramic and metallic materials, whose heat resistance and selective properties are key to this work. Part of the development of the emitter structures was also the need for pretreatment of the substrate itself, where great emphasis was placed on the purity of materials and surface roughness. Since ceramic materials cannot achieve a surface roughness so low that the desired structures can be formed, these materials have been purposefully used primarily for the purpose of combining the base material with thin layers of other high temperature material. Their compatibility and suitability were verified in terms of adhesion and subsequent heat resistance. The main material for the formation of fine structures was purposefully chosen tungsten, for which we verified the influence of the formed structure on the emissivity as well as the thermal stability during long-term exposure to high temperatures. The work thus represents not only a new method of creating very fine structures, which are not normally formed in such subtlety, but also opens the way to new possibilities of combining more materials to achieve the required selectivity of the thermophotovoltaic emitter.
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Measuring of emissivity of wet and dry surfaces
Brzobohatý, Tomáš ; Janotková, Eva (referee) ; Pavelek, Milan (advisor)
The objective of this thesis is to create summary of emissivity of wet surfaces, emissivity of rime surfaces and emissivity of dry surfaces. The next objective is to create materials for termovision measurement and find the use for this materials for practice. Theoretical part of thesis deals with a theory of ways of heat transfer (radiation mainly), description of emisivity concept, description of emisivity finding ways and the show emissivity of mesuared materials from avaible sources for working hypothesis. Emissivity of dry, wet and rime samples were measured as the experimental part of thesis. Experimental part of thesis consist of experiment description, working hypothesis, measuring instruments and measuring area description, measuring proces description and presentation of measured results. Obtained dependences are benefits for termovision measurent, energy evaluation and the thermal state microclimate simulations.
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Thermomechanical tire model
Vaníček, Jan ; Štětina, Josef (referee) ; Porteš, Petr (advisor)
This diploma thesis is about thermomechanics of passenger car tires. The research part dealing with existing tire models is followed by the practical part. The practical part is based on the designs of thermomechanical models. The first model determines a dependence of temperature on the air pressure inside a tire when a temperature changes. The second thermomechanical model captures all the heat fluxes which affect a tire while a vehicle is in motion. The third thermomechanical model calculates temperatures of parts of the tire during driving tests. All models are programmed in MATLAB.
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Non-contact temperature measurement
Negrová, Stefania ; Merenus, Ondřej (referee) ; Hermanský, Dominik (advisor)
The bachelor thesis deals with non-contact temperature measurement, which is currently used for thermodiagnostics and prediction of temperature behavior of machines. In the thesis is described a basic overview of contact and non-contact methods of temperature determination. It focuses primarily on thermography and its uses for machine tools and includes two simple and clear measurements use of thermocamera.
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Utilization of infrared camera for temperature measurement of electrical machines
Líbal, Jan ; Aubrecht, Vladimír (referee) ; Kuchyňková, Hana (advisor)
The master‘s thesis deals with utilization of infrared camera for temperature measurement of electrical machines. The first part describes non-contact temperature measuring, the second part describes principle of sensors that evaluate quantity of incident infrared radiation. In the next part there is termovision camera SAT-HY 6800 presented and the instructional manual for SAT Report computer programme created. This computer programme is used for analyzing of termovision pictures from the SAT-HY 6800 termovison camera. The chapter 7 describes temperature measuring of one-phase asynchronous motor type J22TO484. The chapter 8 describes temperature measuring of semiconductor components of EC motor G6 series. Both of these motors are produced by ATAS elektromotory Náchod a.s. The last part of the thesis describes creation of animation of one-phase asynchronous motor type J22TO455. The animation was created in 3ds Max computer programme.
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Study efficiency of modern thermal insulation for buildings
Šot, Petr ; auditor, Karel Trojan, Brno, energetický (referee) ; Šťastník, Stanislav (advisor)
The bachelor´s thesis deals with the problem of thermoreflect insulation. The small part of thesis focuses on the energy demand of buildings and its problems. Then the greater extent is analysed problems by heat transfer of material. It includes effects arising from the individual methods of heat transfer and defines the level of expression of individual methods of heat transfer in materials. The thesis presents an overview of experimental methods for determining thermal insulating properties of insulators. Then there is shown a selection of the most widespread insulation materials used in today´s construction. It includes the division of insulators in terms of used materials and subsequent classification of the most used materials in these groups. Another part of thesis deals with the thermoreflect isolation. There are mentioned the necessary concepts for the study of thermoreflect thermal insulation, which include the emissivity surface, the coefficient of mutual radiation and translucency of the material. Then there is described the method heat transfer of thermoreflect isolation. On the next there are presented experimental methods of determining thermal insulating properties thermoreflect thermal-insulating material. The thesis also includes a practical part, which contains the measurement results on a small range of samples taken termoreflection insulators. In the end there is mentioned a brief realization of thermoreflection thermal insulation materials in buildings.
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ThermaCAM PM595 in practical use
Švábeník, Petr ; Křivák, Petr (referee) ; Hudcová, Lucie (advisor)
The thesis presents study of generation of thermal (infrared) radiation, its properties and ways of measuring. The possible used sensors of this thermal radiation are described. A thermacam is using these sensing units so there are written benefits of this measurement. Some suggestions for practical use and specific submissions to measure are written.
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The heat build-up of tap-off units of busbar trunking system in relationship to their surfacing.
Forejtník, Jan ; Radil, Lukáš (referee) ; Foral, Štěpán (advisor)
This study is dedicated to the effect of surface modification on lid warming of busbar trunking system BD2 which is manufactured by Siemens company in Mohelnice town (CZ). By using experimental methods, it investigates heat transfer by radiation and natural convection. It evaluates which type of surface modification is more effective by transfer heat. This study uses a method of emisivity comparison and a procedure given in standards for heat up test afterwards. It led to recognition, that various colour shades used on busbar system have similar high emissivity. Smooth colour spraying transfers heat a bit more effectively than rough colour spraying. Outputs of supplementary measurements give basis for numerical simulations in SolidWorks software. Numerical analysis assists to interpret results, for example by sensitivity study of heat transfer depending on emissivity.
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Calculation methods for tube banks heat exchanger
Housírek, Jiří ; Jegla, Zdeněk (referee) ; Kilkovský, Bohuslav (advisor)
This diploma thesis deals with calculation methods of heat exchanger with cross-flow tube bundle. The first part of the thesis contains summary of generally known basic calculation relations used in calculations of heat exchangers and a detailed description of a given heat exchanger.The second part of the thesis provides a description of available calculation methods of a given aparatus required for its thermal and hydraulic calculation. The final part describes application POST in 1.0 which has been formed on the basis of these calculation methods. Using this application check calculation of exchanger with cross-flow tube bundle was carried out and gained figures compared with results gained by means of professional calculation program HTRI.
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Measurement of surface temperatures in mechanical engineering
Stránský, Marek ; Slaný, Martin (referee) ; Polzer, Aleš (advisor)
This work deals with contact and non-contact methods of surface temperature measurement. The work contains a list and formulations of basic terms and laws of thermodynamics. Furthermore, the work deals with the description and comparison of the properties and use of certain devices for contact and non-contact surface temperature measurement. The experimental part is focused on dependence of the turning speed on the turning knife thermal stress. Subsurface thermocouples, surface thermocouples and thermovision were used for the temperature detection. The subsurface temperatures were afterwards used (as data inputs) for the inverse calculation of surface temperatures. All results obtained were then compared to each other.
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