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Hot water preparation technology
Štipský, Pavel ; Pech, Ondřej (referee) ; Štětina, Josef (advisor)
This bachelor thesis deals with methods of hot water preparation in households and other non-industrial objects. In first part there are described hot water preparation technologies. In second part there are designed parameters of tank and tankless water heater for family house using standard ČSN 06 0320. Based on these parameters there are chosen water heaters which use different fuels and for them there are calculated their annual operating costs for heating water. At the end of this thesis there is a catalogue containing selected water heating devices and their basic parameters.
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Research on Effective Methods of Exhausting
Pech, Ondřej ; Kratochvíl, Zdeněk (referee) ; Černecký,, Jozef (referee) ; Pavelek, Milan (advisor)
Many production technologies generate a variety of gas pollutants, which are unhealthy. The aim is therefore to minimize the content of such gas pollutants in the work environment. The highest capture efficiency of gas pollutants offers the local exhausting. Its disadvantage is the necessity to surround the source of pollutants, or to be as close as possible which is usually not technically or technologically possible. A possible alternative is to use a reinforced exhaust system that achieves greater capture distances. In the initial stage of the solution of the dissertation, a review of reinforced exhaust systems was carried out. Further, an existing measurement system was modified for measurements with the partition above the exhaust slot and the measurement system was partially automated. In order to investigate the case with pollutants having a lower density than the air, the workbench - the partition was moved above the exhaust slot. Based on of the literature review, a modification of the reinforced slot exhaust system was proposed. The modification consisted in the adjustment of the air inlet adjustment where a set of holes and a tube assembly were used instead of the slot. Such setup allowed for higher flow turbulence and thus for an increased exhaust efficiency. Subsequently, the inlet streams from the slot, holes and tubes were visualized by the smoke method. Further measurements were carried out by the tracer gas method for the determination of the exhaust efficiency. Measurements of velocity fields in front of the proposed configurations of the reinforced slot exhaust hood were also carried out. In conclusion, an energy performance assessment was carried out by means of the measurement of the electric power input to the fans with the determination of the electric loss power.
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Experimental study of turbulence downstream of a wire mesh
Uřičář, Filip ; Pech, Ondřej (referee) ; Lízal, František (advisor)
This bachelor's thesis is focused on the convection behind a mesh grid and consists of three parts. The first part presents current of knowledge in the generation and damping of the turbulence by the mesh grid. The second part presents experimental results of the measurement. The third part of the thesis is focused on experimental data processing and analysis. The method of hot wire anemometry was chosen for the speed measurement, namely Streamline by Dantec and for experimental purposes track had been constructed in the Laboratory of Ventilation Systems at the Faculty of Mechanical Engineering, Brno University of Technology. Based on the knowledge gained from the study of literature and the consultations, calculations and technical possibilities of the instruments used, grid measurements were performed for convection from 150 to 300 liters per minute, which was sufficient to generate turbulent flow. For the experiment, a solid grid through which the fluid flows has been chosen, due to feasibility of the experiment.
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Measurement of capture efficiency of the reinforced slot exhaust system with a workbench
Šíp, Jan ; Zaremba, Matouš (referee) ; Pech, Ondřej (advisor)
The aim of this bachelor thesis is an experimental research on the efficiency of enclose reinforced slot exhaust hood situated over a workbench in the case of different ratios of momentum flux of supplied and the exhausted air flows. Exhaustion efficiency was also measured during the situation when the exhaust hood works as a classical one, i.e. without air supplied by radial slot. The workbench is situated on the upper edge of the exhaust slot opening. For measuring of the exhaustion efficiency was used a tracer gas method, such as trace gas was used carbon dioxide. For data evaluation was used the software Surfer. In the conclusion there are processed measurement uncertainties.
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Heating system of a Low-energy house
Jankola, Mario ; Pech, Ondřej (referee) ; Katolický, Jaroslav (advisor)
This master’s thesis pertains to heating practices of low-energy houses using a heat pump (example 1) and low-temperature condensing boiler (example 2). The first part of the work contains calculations of suggested building’s heat efficiency and of under-floor heating. The second part of the work includes estimates of seasonal heating factors for construction with a heat pump. Based on the comparison: both of these heating systems are recommended; the capacity of the warm water container is established; and safety elements are chosen. Furthermore, a system of regulation for warm water heating is determined, and a curve of equithermal regulation for heating is calculated. Both of the recommended heating possibilities include calculations of costs of supplies and manufacturing, as well as blueprints for construction.
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Machining of hard materials
Pech, Ondřej ; Kalivoda, Milan (referee) ; Osička, Karel (advisor)
The objective of this paper is to analyse the issue of machining of hard materials on Swiss-type automatic lathes at Decoleta, a.s. In the form of research, analyses are being done of the materials used, possibilities of the available cutting tools and suitable tooling materials. The current technology used in the production of two different stainless steel elements is further being analysed in detail, including the subsequent suggestion of rationalisation actions. These actions include, mainly, the design of new tools from CBN for both elements, which shall replace the current tools made of sintered carbide, but also reworking of production technology for the Pin on another more suitable type of machine, including a new CNC program and complete drawings.
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Estimation of spray cone angle from atomization nozzles using image based methods
Štafa, Ondřej ; Pech, Ondřej (referee) ; Jedelský, Jan (advisor)
The aim of the bachelor thesis is to estimate spray cone angle. The theoretical part deals with basic principles of atomization, spray structure and spray processing methods including image based methods. The experimental part describes steps of spray cone angle estimation in several specially designed softwares. Advantages and disadvantages of these programmes were evaluated with great emphasis on functionality. Results contain data of spray cone angle values depending on distance between atomization nozzle and spray stream level.
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Design of a space heating system and hot water heating for family guest-house
Nykl, František ; Pech, Ondřej (referee) ; Katolický, Jaroslav (advisor)
This diploma thesis describes the detailed design of heating and hot water heating for a family quest-house. At first the reader is introduced to the designed building, its design and construction elements. The thesis presents the calculation procedure and design of the heating system. This consists of designing radiators, the heat source, the circulating pumps, regulations of the heating system and the design of its security elements. The thesis also describes the design of the heat exchanger for hot water and security. In conclusion, an evaluation of operating costs with the recommended solution for their reduction. The thesis also includes drawing documentation of structural drawings, heating and unrolled schema that is mentioned in the attachment.
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Influence of location of reinforced slot exhaust hood above work table on capture efficiency
Winkler, Martin ; Pech, Ondřej (referee) ; Pavelek, Milan (advisor)
The present thesis explores the reinforced exhaust slot system above work table. Its objective was to measure the capture efficiency in front of the suction extension in various elevation levels of the workbench, taking into consideration four mobility ratios, while in the first case we performed traditional suction. The thesis also presents the results of capture efficiency measurements recorded in figures and tables of measured values. The conclusion analyzes the uncertainty in performed measurements.
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