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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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The capture efficiency research of REEXS with the work bench
Pavlas, David ; Pavelek, Milan (referee) ; Janotková, Eva (advisor)
Proposed diploma work provides capture efficiency measurements of generated pollution captured by reinforced slot exhaust system in modification with work bench using tracer gas method. There are shown results of capture efficiency for traditional exhausting (no radial air added) and reinforced exhausting (using radial air supply effect) in this work. This study also conatins the comparison and discusion of obtained measurement results with measurement errors and uncertainties.
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Air-cinditioning of hotel kitchen
Mazáč, Ondřej ; Pavelek, Milan (referee) ; Janotková, Eva (advisor)
The objective of my thesis was to suggest and size the equipment for a hotel kitchen air-conditioning according to the given parameters. This thesis deals with the calculation of the amount of circulating air, heat loss and profit and the psychometric calculation for summer and winter operation. It also contains the design of air channels, terminal components, air-conditioning unit and ventilation of machine room. Furthermore, it comprises of the suggestion of measurement system and regulation, estimation of energy demand, technical report and list of material items. The calculation is equipped with drawing documentation.
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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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Air-conditioning and ventilation of a restaurant
Urbanová, Magdaléna ; Pavelek, Milan (referee) ; Janotková, Eva (advisor)
Diploma thesis is focused on the design of restaurant's air-condition system for 60 persons as well as air-condition system for adjacent kitchen. The work consists of an introduction to the problematic of air-condition systems and its arrangement in the project. Diploma thesis consists of two parts - computational and design. Computational part includes computations of a quantity of an aeration air, calculation of thermal losses, stress and psychrometric evaluation of operation during summer and winter. Design part consists of designing of location and slot diffuser dimensioning, design of air conduct paths, its dimensioning and calculation of pressure losses. This work also includes designing of ventilation of machine-room, selection of air-condition units and its measurement and regulation. Drawing documentation and material specifications are also part of this diploma thesis.
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Development of Simulation Tool for Semi-Hermetic Compressor with the Objectives to Improve Efficiency
Tuhovčák, Ján ; Masaryk, Michal (referee) ; Pavelek, Milan (referee) ; Jícha, Miroslav (advisor)
Compressors are widely used across the all technical fields and current pressure on ecology increases the demand for more effective compressor with economical operation costs. The reasons for inefficiencies must be identified during the development process of a new compressor, where simulation tools might become very useful. There are many different tools for compressor analysis and choosing the right one is mostly dependent on the level of detail that must be analyzed. Models based on energy balance seem to be appropriate when the global parameters of a compressor are demanded. These models offer quick results with reasonable degree of accuracy in terms of basic compressor characteristics. The goal of this thesis is to develop such a simulation tool for a reciprocating compressor. The tool can predict compressor behavior based on compressor dimensions and valve properties. The processes inside the cylinder and heat transfer between the components of a compressor are analyzed using energy balance equation. Simulation tools were verified and experimentally validated using two different types of compressors, therefore they might be used for any reciprocating compressor under some conditions. Mathematical solution was developed in Matlab and therefore it is possible to add new sub-models or to couple the actual model with other simulation tools. This work also contains an analysis of heat transfer models used to predict heat transfer coefficient inside the cylinder and comparison with complex numerical approach. Impact of heat transfer on the compressor efficiency was evaluated too.
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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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