This thesis is dedicated to efficiency increase of one phase induction machine through material change of induction cage and rotor slot shape optimization under the condition of maintaining the same locked-rotor torque. In the first part of this thesis is the explanation of induction machine principles. Next is the comparison of measured and simulated parameters of small one phase machine from ATAS company. The following part is dedicated to the analysis of rotor slot shape and ring size influence on machine parameters when using pure aluminum instead of resistive alloy. The next chapter deals with slot shape optimization in the program RMxprt, controlled by genetic algorithm written in MATLAB interface. In the final part are the resultant slot shapes simulated in Ansys Maxwell using finite element method and then the measured, simulated and expected parameters are compared.

In some applications, the piston steam engine may be more suitable than the technology currently used. The thesis deals with the analysis of its advantages, weaknesses and possibilities of use, which are offered. Introduces the principles and functions of piston steam engines. It also contains a thermodynamic design based on a specific assignment and a feasibility assessment.

This thesis focuses on optimization and increasing the efficiency of high-power DC/DC switching converters with transformer (switching power supplies). The work focuses mainly on using converters with flyback topology for high power, even though it is a common belief that this type of converter is not suitable for high power. This topology was selected because of potentially better achievable parameters, especially the efficiency, in comparison to a commonly used forward converter – in a flyback converter, losses are produced only in one magnetic component (transformer) in contrast to two components (transformer and inductor) in the forward converter. Compared to resonant and quasi-resonant converters, the flyback converter is easily controllable in the whole output voltage and current range. To make the flyback converter favorable for a high-power use, some innovative circuit modifications were made and modern semiconductor and passive components were used. Theoretical part of the work deals with efficiency optimization of the flyback converter, based on analytical solution. Operating parameters of the converter – switching frequency and parameters of the transformer (flux density and numbers of turns) are commonly only guessed or chosen from experience. The objective of this part is a mathematically exact determination of these parameters to achieve lowest total losses of the converter for given input parameters. In a certain case, it was possible to obtain the final solution analytically, in other cases the final solution step had to be done with a help of software. A prototype of a 12-kW switching power supply with a flyback converter was constructed to validate the proposed solutions and methods. The power supply fits into a space of only 33x33x16 cm. Modern semiconductors based on the silicon-carbide (SiC) technology (MOS-FET transistors and diodes) were used. After bringing the converter to a full-power operation, an efficiency of 96.8 % of the DC/DC converter was measured. High efficiency was obtained for a wide range of output parameters. A certain comparison with a forward converter with the same output parameters is done in the work. Not only from an efficiency point of view, the flyback converter seems very perspective.

This diploma thesis deals with the design of the air-conditioning unit of the wellness center in Brno and includes experimental measurement of HEPA filters. The thesis is divided into three main parts: the theoretical part, the experimental part and the air-conditioning unit design. The theoretical part of the thesis contains basic introduction to air filters. The experimental part aims to evaluate the pressure loss and the effectiveness of HEPA filters. The last part of the diploma thesis is practically focused on the comparison of three air-conditioning unit of the wellness center.

In the introductory part of this diploma thesis the pesticidal substances and their legislative requirements in drinking water are described. This is followed by a description of technologies in which pesticides can be removed and used in water treatment plants. In the practical part of the thesis is described description of the experimental procedure of the removal of pesticides on two selected adsorption materials (Filtrasorb F100 and Bayoxide E33) and subsequently this experiment is evaluated.

This master’s thesis first deals with the theory concerning induction motor. It briefly desbribes the construction of three-phase induction motors, the generation of tractive force, power flow with loss distribution and also torque characteristic. In the next part an analytical calculation of the parameters of equivalent circuit for an existing induction motor with known dimensions is performed. After the calculation it is possible to find out the rated parameters of the motor, which makes it possible to further compare results with the values obtained by other methods. The next step was to create a model of the motor in RMxprt program, which is later also translated to ANSYS Maxwell 2D model. Simulations were carried out in both interfaces. As the next step the results obtained by the three methods are compared with measured values and also evaluated. The final part of the thesis focuses on the optimization of the magnetic circuit for higher frequencies. Efficiency of the modified induction motor is examined for higher frequencies using RMxprt Optimetrics and this procedure is performed for both default and alternative electrical steel materials.

The aim of the thesis was to study the Energy Models of Linear Axes with Ball Screws and Servo Drives, to analyze the individual parts of the axis with respect to losses, the methodology of calculating the losses on the electrical part and the mechanical part of the drive and creating a complex algorithm that calculates the energy consumed for the specified motion. The thesis is divided into a theoretical and practical part, where the theoretical part is divided into the treatise on the electrical part of the axis and its losses and the part that deals with the mechanical part and its losses. The calculation is divided into the basic verification algorithm and the calculation on the given example. Each calculation is calculated for both linear acceleration and S-curve acceleration. For both types of acceleration, the result of energy and its course over time is also the waveforms of position, velocity, acceleration, angular acceleration, moments, powers, power, speed and currents over time.

Determining the characteristics of piston engines with a propeller is a complex task. Accurate calculations are based on engine and propeller characteristics from the manufacturers, which are, however, quite demanding. It is also possible to use simplified models that can predict the achievable values of propeller efficiency and fuel consumption. They are based on a simple propeller efficiency and maximum power. However, these models are often very inaccurate, which is a significant disadvantage. Therefore, it is possible to use the universal characteristics of propeller propulsion units, which offers a more accurate calculation of power and fuel consumption using a relatively simple model. The diploma thesis deals with a summary description of all characteristics of reciprocating internal combustion engines and propellers. A mathematical model was created here, which works according to a certain algorithm based on the joint work of the engine and the propeller. This model can predict the required power and fuel consumption in different flight modes much more accurately. The results were applied to the performance of ultralight aircraft, especially to the range, which was significantly increased.

This thesis deals with the occurrence of microplastics in water, the reasons for their potential elimination, and the possibilities leading to that. More specifically, it focuses on flotation as a process for removing microplastics from water. Flotation is further described from a theoretical point of view and its mathematical model is developed. The wettability of selected polymers is measured. The experiment performed to determine the efficiency of flotation as a process of treating water from microplastics is described. This efficiency is further compared to measured wettability.

This diploma thesis concentrates on the properties characterization of new organic materials for solar cells. In the theoretical part, there is a solar cells themed literature search, there is described a mechanism of conversion of solar energy, factors influencing photovoltaic conversion efficiency and materials using for preparation of organic solar cells. The practical part includes the preparation of solar cells and characterization of optical and electrical properties of the studied materials in thin layers and solutions. Used materials were conjugated polymers and derivatives of fullerenes.