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THERMAL DECOMPOSITION OF SOLID BIOFUELS AND ASSOCIATED FINE PARTICLE GENERATION
Sitek, Tomáš ; Ličbinský, Roman (referee) ; Svěrák, Tomáš (referee) ; Pospíšil, Jiří (advisor)
Despite otherwise indisputable advantages, biomass burning is associated with significant emissions of fine particles. The different behavior of dissimilar types of biomass during thermal decomposition can be explained to some extent by the different composition, i.e. the different content of cellulose, hemicellulose and lignin. The main aim of this work was to find the emission characteristics of these three components during heating in a thermogravimetric analyzer. The monitored parameters were the heating rate and the oxygen content in the combustion atmosphere. The output is the dependence of the sample mass and also the corresponding distributions of particles on the temperature. The results show considerable differences between the individual samples, but in general the pyrolysis of cellulose produces the highest particle emissions. Higher oxygen content in the combustion atmosphere and lower heating rates cause earlier sample decomposition and reduce particulate emissions. This is followed by an evaluation of the transferability to a sample of a real biomass based on its known composition using a simple weighted arithmetic mean. Useful information on particle sampling and electron microscope visualization, supplemented by images of particles from the pyrolysis of selected samples can also be found in this work.
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Aerosol particles morphology
Odehnalová Šamanová, Jaroslava ; Linda, Jakub (referee) ; Pospíšil, Jiří (advisor)
This thesis focuses on airborne Particulate Matter (PM), the floating dust that surrounds human beings every day, its composition, morphology, size and concentrations in the air. The first, introductory part of the thesis, describes the basic concepts, properties and health risks associated with aerosol particles, and relevant legislation. The second, experimental part of the thesis, describes the instruments used, followed by the results of emission sampling and immission sampling, and a comparison of measured concentrations in three selected locations: in a village, in a city, and in a family house. The third part, the analysis, investigates freely available air pollution immission monitoring data, including long-term data, data from occasional events such as New Year’s fireworks, or sporadic occurrences such as a forest fire in České Švýcarsko national park. The conclusion summarises the achieved results, and the appendix consists of a catalouge of dust particles, in which all emission samplings carried out within the experimental part of the thesis are listed.
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Dispersion of particulate matter pollution from electric vehicles in urban areas using CFD
Lipka, Jakub ; Pospíšil, Jiří (referee) ; Linda, Jakub (advisor)
There is an opinion across the society, that electric vehicles (EV) are emission-free alternative to vehicles using internal combustion engines (ICEV). This is not true. Although electric vehicles do not produce emissions connected to internal combustion, they still produce non-combustion emissions that are emitted into surrounding air. Non-combustion emissions in question are brake wear particles (BWP), tire wear particles (TWP) and road wear particles (RWP). These emissions, due to EV’s greater mass, tend to be higher compared to ICEVs. Therefore, in this thesis, model of dispersion of non-combustion emissions generated by EVs was created using CFD consisting of two models – airflow model around EV and particle dispersion model. It was found that those emissions are captured and distributed by airflow, mainly thanks to vortices generated in the wake zone behind the vehicle. Those particles can be suspended up to 1,9 m into the air and up to 2,5 m laterally away from the vehicle. Thanks to that there is a risk of pedestrian inhaling air with high concentration of those particles in places near roads like pavements.
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Evaluation of real PV system operation
Macák, Vít ; Gregorovičová, Eva (referee) ; Pospíšil, Jiří (advisor)
This bachelor thesis covers photovoltaic systems, their various configurations and main components. It analyses a specific installation on a single-family house, evaluating the operational data and the economic return of the system. The thesis also provides recommendations for future operations and system expansion options.
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Multi-stage impactor
Kojecký, Dalibor ; Sitek, Tomáš (referee) ; Pospíšil, Jiří (advisor)
This master’s thesis is focused on the problem of laboratory capture of fine particles by the impaction method. The introductory chapter is devoted to the investigation of fine particles in air and the impact of air pollution on humans and the environment. The second chapter intro-duces the history of impaction devices, describes the principles of the cascade impactor, and explains the theory behind fine particle capture by changing the direction of the airflow carrying the particles and their capture when they hit a solid wall. In the practical part of the thesis, a computational procedure is developed using the Python programming language for a custom design of a multi-stage impactor. The parameters obtained from the developed computational software are compared with those of a commercial impactor available at the faculty of the school. According to the developed computational procedure, a custom multi-stage impactor is designed for particle separation in the range of PM0.5 to PM0.1.
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Mobile island photovoltaic system
Zelenka, Petr ; Baláš, Marek (referee) ; Pospíšil, Jiří (advisor)
The mobile island photovoltaic system is a technology designed for electricity generation in locations without traditional electrical grid infrastructure. This compact portable device combines solar panels with batteries and other components, such as charge controllers and inverters. Its mobile nature allows deployment in remote locations (isolated houses, military bases, mountain cottages, campsites) and in emergency situations. The first part of the bachelor's thesis focuses on the issue of generating electrical energy through photovoltaic conversion and its storage in batteries, while the experimental part focuses on measuring the characteristics of photovoltaic panels with different inclinations and shading. It also models the utilization of solar energy under various sunlight conditions. The thesis provides an overall perspective on the importance of mobile island photovoltaic systems and their potential in the field of renewable energy and sustainable development.
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Evaluation of real heat pump installation operation
Pliml, Patrik ; Gregorovičová, Eva (referee) ; Pospíšil, Jiří (advisor)
The bachelor thesis on heat pumps focuses on various aspects related to heat pumps, including heat transfer or economic benefits. The function of the heat pump is described in a review way. Furthermore, the main heat pump components, low temperature energy sources and different types of heat pumps are presented. The main part of the thesis is focused on the evaluation of the heating of a family house after a real installation of an older heat pump. To solve this part, own measurements were used as well as a calculator to calculate the heat loss of the heated building. These results formed the basis for the evaluation of the system in terms of operational, technical, and economic aspects. A table was created in which the data on the electricity con-sumption for the heating period was kept in order to compare the heat losses obtained from this calculator. The aim of the last part of the bachelor's thesis was to design the heat pump in order to reduce the electricity requirements for heating. This requirement is based on the results obtained in the previous part and corresponds to the current standards of new heat pump technologies. The output of the thesis is a new heat pump design in order to reduce the electricity consumption.
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Heat accumulator design
Rigby, Jakub ; Šnajdárek, Ladislav (referee) ; Pospíšil, Jiří (advisor)
This thesis deals with the issue of thermal energy storage with the aim of designing an original heat storage concept using crushed rocks. The introduction of the thesis summarizes the available literature and the latest findings in the field of heat storage. It is followed by a presentation of realized projects that integrate crushed rocks as a storage material. The practical part of the thesis focuses on detailed balance and design calculations of the heat storage. Based on these calculations, an innovative heat storage concept is designed. The conclusion of the thesis summarizes the results of the numerical simulations and performs an economic evaluation of the proposed heat storage.
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Heat storage technology with subsequent electricity production
Procházka, Artuš ; Preisler, Lukáš (referee) ; Pospíšil, Jiří (advisor)
This thesis concerns itself with problematics of accumulation of electric energy, especially with one of the future technologies and that is the Carnot batteries. Focus will be directed towards different types of charging the batteries, by charging the batteries is meant transformation of electric energy into a heat energy, and towards technologies of heat accumulators, in which the heat will be stored. Different realizations and future projects of Carnot batteries will also be included in this thesis, same goes for the comparison with other technologies for accumulation and for comparison between diverse Carnot battery technologies. The simple calculation of Carnot battery will be done on the end of thesis.
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Passively discharged industrial sand heat accumulator
Urbánek, Štěpán ; Kudela, Libor (referee) ; Pospíšil, Jiří (advisor)
This thesis focuses on thermal energy storage in granular materials, primarily sand. The first part introduces the concept of thermal energy storage in granular materials, the structural design of this energy storage method, and its implementation. Subsequently, a concept of a passively discharged thermal energy storage system is developed for the premises of building C3 in the VUT FSI campus. Based on this concept, a detailed structural design is created, which is finally subjected to verification of temperature states. Finally, a technical and economic evaluation is performed.
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