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Cleaning of ventilation systems and potential energy savings
Lapáček, Milan ; Rubina, Aleš (referee) ; Máša, Vítězslav (advisor)
The main aim of this thesis is to explore fouling of air ducts and its influence on energy consumption of HVAC systems. The first part focuses on typical parts that create the IAQ in buildings and on evaluating energy consumption of air transportation. The following section deals with the theories of fluid flow, flow regimes and pressure losses that are created as a side effect. The thesis outlines possible methods of assessing the impact of pollution with an emphasis on pressure losses and their influence on the fan power consumption. The actual experimental measurement, conducted in a selected industrial plant, is focused on an influence of cleanness of textile diffuser on HVAC device power consumption. For the further research of this process, measuring equipment with suitable measurement method is designed and constructed.
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Biomass and waste gasification and cogeneration by the help of microturbine
Kašpar, Matěj ; Najser,, Jan (referee) ; Baláš, Marek (advisor)
This diploma thesis investigate the question of combined production of heat and power by the gasification of biomass. The introduction describes basic dilemma energy conversion from biomass. Further, special attention at the gasification technology and it´s usage at combined heat and power production is paid. The main section includes schematic proposal cycle with use of microturbine 80 [kWe] as well as basic calculation, which serves as a base for folowing project optimization. For discussed optimization is made concept of configuration, thermal and aerodynamics calculation for both heat exchangers B1 and B2. Last but not least these heat exangers were compared by different aspects such as influence of deposits on power transfer and pressure loss. At the end of the work calculated numeric values are discussed and the project of heat exchanger with it´s advantages for practise are summarised.
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New Elements of Heat Transfer Efficiency Improvement in Systems and Units
Turek, Vojtěch ; Klemeš,, Jiří (referee) ; Odstrčil, Miloslav (referee) ; Jegla, Zdeněk (advisor)
Zvýšení efektivity výměny tepla vede k poklesu spotřeby energie, což se následně projeví sníženými provozními náklady, poklesem produkce emisí a potažmo také snížením dopadu na životní prostředí. Běžné způsoby zefektivňování přenosu tepla jako např. přidání žeber či vestaveb do trubek ovšem nemusí být vždy vhodné nebo proveditelné -- zvláště při rekuperaci tepla z proudů s vysokou zanášivostí. Jelikož intenzita přestupu tepla závisí i na charakteru proudění, distribuci toku a zanášení, které lze všechny výrazně ovlivnit tvarem jednotlivých součástí distribučního systému, bylo sestaveno několik zjednodušených modelů pro rychlou a dostatečně přesnou predikci distribuce a také aplikace pro tvarovou optimalizaci distribučních systémů využívající právě tyto modely. Přesnost jednoho z modelů byla dále zvýšena pomocí dat získaných analýzou 282 distribučních systémů v softwaru ANSYS FLUENT. Vytvořené aplikace pak lze využít během návrhu zařízení na výměnu tepla ke zvýšení jejich výkonu a spolehlivosti.
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The effect of boiler tube bundle fouling on its service life
Volná, Kateřina ; Ing. Zdeněk JŮZA, Ph.D., MBA (referee) ; Naď, Martin (advisor)
Fouling of tube bundles in boilers on the flue gas side affects not only the service life, but also the boiler heat output and increases maintenance and operating costs. Therefore, it is necessary to minimize or completely eliminate this process. This thesis focuses on comparison of the service life and the heat output of the tube bundles with and without deposit in the coal fired boiler. Simulations of flue gas flow in area of tube bundles with and without deposit are performed using ANSYS Fluent software, which shows that the surface of tube bundles with deposit is much less heated than the surface without deposit. The thermal loads of tubes obtained by the CFD analysis are applied to the model, which is created in the program ANSYS Mechanical, where the calculation of the temperature field in the cross section of the pipe is realized. The effect of fouling on creep life and heat output is then evaluated based on simulation results. The results show that fouling increases creep life, but significantly reduces heat output of heavily fouled tubes. Hence the flue gas flows at a higher temperature to the rest of the tube bundle, and the service life of those tubes will therefore probably decrease.
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Operating fouling of process and power equipment
Sénáši, Martin ; Pačíska, Tomáš (referee) ; Jegla, Zdeněk (advisor)
Bachelor thesis describes the issue of fouling of heat exchangers. This thesis briefly describes the fouling mechanisms and introduces the issue of consideration fouling in the design of heat exchangers. From gained information subsequently on simple calculation examples demonstrate using basic calculation methods impact of fouling on process stream. It also describes the impact of fouling on the technical and economic solutions of heat exchangers.
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Application of Polymeric Hollow-Fiber Membranes in Air Filtration
Bulejko, Pavel ; Dohnal, Mirko (referee) ; Friess, Karel (referee) ; Svěrák, Tomáš (advisor)
Membrány z dutých vláken jsou široce využívány v aplikacích týkajících se úpravy kapalin jako např. při čištění odpadních vod, v membránových kontaktorech a bioreaktorech, membránové destilaci apod. I když jsou často využívány při separacích směsí plynů, je jejich použití pro mechanickou filtraci aerosolů velmi vzácné. Tato práce se zabývá filtrací vzduchu pomocí polypropylenových membrán z dutých vláken včetně jejich filtrační účinnosti, tlakových ztrát a také zanášením při dlouhodobé filtraci. Filtrační účinnost byla proměřena za použití různých aerosolů jako TiO2 a síran amonný. Tlakové ztráty byly měřeny při různých konfiguracích, tj. různé filtrační ploše a průměru vlákna membrány. Zanášení membrán bylo testováno použitím normovaného prachu definovaného normou ANSI/ASHRAE 52.2. Predikční modely pro filtrační účinnost a permeabilitu/tlakovou ztrátu membrány byly aplikovány na parametry membrán z dutých vláken a porovnány. Tyto membrány mají velikost pórů kolem 90 nm a poměrně nízkou porositu a tím vysoký potenciál pro separaci nanočástic ze vzduchu. Dále byla provedena analýza filtračního koláče a vyhodnocení energetických nároků a porovnány s teoretickými modely. V závěru práce je nastíněn odhad ceny životního cyklu při filtraci pomocí těchto membrán.
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Effect of exchanger fouling and heat transfer coefficient
Konopiský, Karel ; Kracík, Petr (referee) ; Baláš, Marek (advisor)
This diploma thesis covers the influence of fouling in heat exchangers and heat transfer coefficient. In the first part of the thesis are covered the characteristics of fouling and its formation, process, and effects on heat transfer surfaces in exchangers. In the next part of the thesis, chemical analysis of cooling water is performed on an extracted sample and the potential of fouling is determined based on the analysis. In the conclusion part, computational models of fouling in the tube side of the heat exchanger are presented; fouling of an actual heat exchanger is calculated and compared with data captured during the operation of the heat exchanger.
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Assessment of the silting streambed river Blata in the village Senice na Hané
Mlčochová, Zuzana ; Julínek, Tomáš (referee) ; Uhmannová, Hana (advisor)
Assessment of the status of a watercourse in urban area The thesis is concerned with an appraisal of water channel of Blata in urban area of Senice na Hané, Olomouc region. Solved segment is located in RK 34,600-34,976. The channel is modified to a rectangular profile which is silted. In the thesis the capacity of channel of primal improvement is assessed as well as the capacity of silted channel before depuration in 2012 and appraisal of causes of silting and concept of new arrangements in order to reduce silting process. The appraisal of current state of channel is designed on the base of nonscouring and nonsilting velocity calculation. Results of capacity of channel were calculated in HEC – RAS 4.1.0 program.
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Modelling of fouling and its influence on technical-economic characteristics of tubular heat transfer equipment in units for thermal processing of wastes
Keliš, Michal ; Kohoutek, Josef (referee) ; Jegla, Zdeněk (advisor)
The main subject of this study is the improvement of predicative ability of previously developed mathematical model for prediction of so-called “fouling critical velocity”. Attention is devoted especially to the flue gas side fouling process on active heat transfer surfaces in tubular heat exchange tube banks installed in waste incineration process plants and also a technical – economic analysis based on obtained results. The model improvement consists among others in taking into account another forces (electrostatic, capillary etc.) haven't yet been considered, which influence the mutual contact between flue gas particles in case of sedimentation fouling or the contact between particles and heat exchanger tube walls respectively. The improved model has therefore more predicative ability to the reality of fouling process. The results are used for technical – economic analysis, which determines an optimal heat exchanger design with respect to fouling. Furthermore, the algorithm of this analysis, essential fouling mechanisms, fouled heat exchanger surface cleaning methods as well as fundamental knowledge of fouling coefficient prediction are presented, whereas the emphasis is placed on industrial tubular heat exchange equipment installed in waste incineration process plants.
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