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Condensing boiler with solar collectors for thermal energy supply of residences
Zeman, Radek ; Špiláček, Michal (referee) ; Pospíšil, Jiří (advisor)
This diploma thesis deals with practical design of heat supply of real house in Libhošť, Nový Jičín. Main strategy of heat supply is gas condensation boiler, that replaces current gas boiler, with solar collector. From known house heat loss we determine temperatures of heating water and power of boiler, that heats the house and hot water. System with solar collector is designed to heat hot water in the house. All necessary equations are calculated both for long term measured meteorological data and for data in year 2015. Heat gains and payback periods of investment in solar system are determined from them. Payback periods are calculated given to price of heat that gas boiler produces. Equations and payback period evaluation are made for systems with one to four solar collectors. There is recommendation at the end of thesis, whether the solar system is advantageous, or not.
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Microfluidic circuit
Zeman, Radek ; Zemanová, Lucie (referee) ; Rudolf, Pavel (advisor)
Microfluidics is a science dealing with flow of a very small amounts of fluids and is mainly connected with medicine and biochemistry. One of a main problem, which this science is facing, is a difficult mixing of fluids due to occurrence of laminar flows. This bachelor thesis contains a design of a microfluidic circuit with Staggered herringbone microfluidic mixer and subsequent implementation of the experiment according to the performed design.
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Hydrodynamic cavitation in minifluidic Venturi nozzle
Zeman, Radek ; Hudec, Martin (referee) ; Rudolf, Pavel (advisor)
This thesis deals with cavitation on a small scale. Conducting experiments on a small scale helps to save time, space, and most importantly money needed for research. Low-energy operation on small scales could accelerate the development of larger-scale devices for practical use in industry. Hydrodynamic cavitation has proven to be a potentially useful tool for some industrial applications, such as water purification. In the practical part of this thesis, a cavitation visualization device operating with flow rates in milliliters per second is proposed. Devices similar to this one could be used in the near future to obtain the benefits previously mentioned, and thus promote research in the field of water purification using hydrodynamic cavitation.
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Engineering design of the Freeze Valve
Zeman, Radek ; Martinec, Jiří (referee) ; Šen, Hugo (advisor)
This bachelor´s thesis deals with practical design of freeze valve for nuclear facilities from both calculation and construction point of view. Firstly, a brief analysis of technologies of fast neutron reactors and reactors with fuel dissolved in melted fluorine salts has been done. The author points out the advantages of their use that may result in becoming an important part of nuclear power engineering. Working fluids are taken from these reactors – liquid sodium and mixture of molten salts NaBF4-NaF. The author deals with choice of suitable construction materials and ways of heat-transfer from working fluid. Secondly, several construction solutions have been assessed and project documentation has been created for some of them. These designs include alternative shapes of valves and canals, where heat exchanging medium flows – Field tube and valve with helix canal. These concepts allow fast intake (conducting away) of heat into the working fluid and after verification on an experimental stand these valves could work in conditions of nuclear facilities. Times of cooling and heating for chosen designs and working fluids are calculated by previously derived dimensionless equations describing transient heat-transfer field with phase change supposing low Biot numbers.
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Wind tunnels for passenger cars
Fabríci, Tomáš ; Zeman, Radek (referee) ; Rudolf, Pavel (advisor)
The bachelor thesis is focused on a wind tunnel usage in the field of automotive industry. Nowadays, they are still the significant part in vehicle aerodynamics research. Specifically, at determining power actuating on vehicle, flow visualization, aero-acoustic measurements. Considering personal vehicles, reducing the drag and reducing the consumption are being accentuated. Aero-acoustic measurements are becoming more and more popular for improvement of driving comfort. Air-flow quality in wind tunnels directly affects the accuracy of the mentioned measurements. The effort is to minimize the accidental turbulence and reach uniform flow quality. Perfect quality of the air-flow will never be reached even though there is an optimal proposal of all sections from which the wind tunnels consist. Very often, we must be satisfied with the accepted flow quality according to the application. However, the progress in the field of computing modeling has reduced the time spent in wind tunnels and moreover it has saved finances. Currently, there is close cooperation between them to reach the best results possible.
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Hydrodynamic cavitation in minifluidic Venturi nozzle
Zeman, Radek ; Hudec, Martin (referee) ; Rudolf, Pavel (advisor)
This thesis deals with cavitation on a small scale. Conducting experiments on a small scale helps to save time, space, and most importantly money needed for research. Low-energy operation on small scales could accelerate the development of larger-scale devices for practical use in industry. Hydrodynamic cavitation has proven to be a potentially useful tool for some industrial applications, such as water purification. In the practical part of this thesis, a cavitation visualization device operating with flow rates in milliliters per second is proposed. Devices similar to this one could be used in the near future to obtain the benefits previously mentioned, and thus promote research in the field of water purification using hydrodynamic cavitation.
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Microfluidic circuit
Zeman, Radek ; Zemanová, Lucie (referee) ; Rudolf, Pavel (advisor)
Microfluidics is a science dealing with flow of a very small amounts of fluids and is mainly connected with medicine and biochemistry. One of a main problem, which this science is facing, is a difficult mixing of fluids due to occurrence of laminar flows. This bachelor thesis contains a design of a microfluidic circuit with Staggered herringbone microfluidic mixer and subsequent implementation of the experiment according to the performed design.
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The Link between Labour Productivity and Firm Competitiveness
ZEMAN, Radek
The goal of this thesis is to assess the link between labour productivity and firm competitiveness. An indispensable condition is to identify appropriate indicators measuring competitiveness. The link is examined in small and medium-sized companies active in manufacturing industry, specifically in section CZ-NACE 10. Manufacture of food products. First, an analysis of labour productivity and selected competitiveness indicators is made. Selected competitiveness indicators are Return on Assets (ROA), Return on Sales (ROS), Current Liquidity and index IN05. The relationship between labour productivity and competitiveness measured by selected indicators is examined by correlation and regression analysis. The significant positive link was found between labour productivity and competitiveness measured by ROA and ROS. Small and Medium-sized companies active in food industry can improve their ROA and ROS, and through this also competitiveness, by increasing their labour productivity. These indicators have also proved to be an appropriate tool for measuring the competitiveness of the company, especially in the food industry in the Czech Republic. The link between labour productivity and competitiveness measured by current liquidity and index IN05 was not explained in more detail.
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Condensing boiler with solar collectors for thermal energy supply of residences
Zeman, Radek ; Špiláček, Michal (referee) ; Pospíšil, Jiří (advisor)
This diploma thesis deals with practical design of heat supply of real house in Libhošť, Nový Jičín. Main strategy of heat supply is gas condensation boiler, that replaces current gas boiler, with solar collector. From known house heat loss we determine temperatures of heating water and power of boiler, that heats the house and hot water. System with solar collector is designed to heat hot water in the house. All necessary equations are calculated both for long term measured meteorological data and for data in year 2015. Heat gains and payback periods of investment in solar system are determined from them. Payback periods are calculated given to price of heat that gas boiler produces. Equations and payback period evaluation are made for systems with one to four solar collectors. There is recommendation at the end of thesis, whether the solar system is advantageous, or not.
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Engineering design of the Freeze Valve
Zeman, Radek ; Martinec, Jiří (referee) ; Šen, Hugo (advisor)
This bachelor´s thesis deals with practical design of freeze valve for nuclear facilities from both calculation and construction point of view. Firstly, a brief analysis of technologies of fast neutron reactors and reactors with fuel dissolved in melted fluorine salts has been done. The author points out the advantages of their use that may result in becoming an important part of nuclear power engineering. Working fluids are taken from these reactors – liquid sodium and mixture of molten salts NaBF4-NaF. The author deals with choice of suitable construction materials and ways of heat-transfer from working fluid. Secondly, several construction solutions have been assessed and project documentation has been created for some of them. These designs include alternative shapes of valves and canals, where heat exchanging medium flows – Field tube and valve with helix canal. These concepts allow fast intake (conducting away) of heat into the working fluid and after verification on an experimental stand these valves could work in conditions of nuclear facilities. Times of cooling and heating for chosen designs and working fluids are calculated by previously derived dimensionless equations describing transient heat-transfer field with phase change supposing low Biot numbers.
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