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Expansion valve replacing with the capillary tube
Devečka, Viktor ; Tuhovčák, Ján (referee) ; Hejčík, Jiří (advisor)
V súčasnosti sa kladie veľký dôraz na znižovanie produkcie emisií, čistotu a kvalitu životného prostredia. Tieto trendy sa týkajú všetkých odvetví, tak isto aj stavebného priemyslu a vykurovania budov. Doposiaľ bolo najrozšírenejším typom vykurovania spaľovanie fosílnych palív. Do popredia sa však dostávajú tepelné čerpadlá a začínajú zaberať výrazný podiel trhu. Kvôli dopytu po tepelných čerpadlách vzrastá počet výrobcov a konkurencia. Cieľom výrobcov je zvyšovanie účinnosti tepelných čerpadiel a zároveň znižovanie výrobných nákladov na dosiahnutie lepšej pozície na trhu. Predložená práca sa zaoberá procesmi prebiehajúcimi v chladivovom okruhu tepelného čerpadla. Skúma správanie chladiva počas kondenzácie a možnosti zvýšenia účinnosti tepelného čerpadla. Zvýšenie účinnosti je dosiahnuté podchladením chladiva počas kondenzácie na zvýšenie tepelných ziskov. To je dosiahnuté zaradením druhého elektronického expanzného ventilu za kondenzátorom. Táto technológia je však finančne náročná. Práca sa zaoberá výpočtom kapiláry na základe praktických meraní, ktorá bude zadržiavať chladivo v kondenzátore a bude plniť podobnú úlohu ako expanzný ventil. Následne sú porovnané výsledky jednotlivých meraní. Výsledky sú porovnané voči jednoduchému systému, kde nedochádza k podchladeniu chladiva. V závere práce je analýza výsledkov jednotlivých systémov.
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Design of a solar system for hot water heating in a family house
Reiskup, Matěj ; Tuhovčák, Ján (referee) ; Jaroš, Michal (advisor)
The thesis discusses the use of solar-powered water heating system in a family home. The introductory chapters present traditional methods of heating water and solar energy concepts. Following chapters compare the advantages and disadvantages of solar-powered water heating with more traditional heating methods and the core parts of such system. Finally a solar-powered heating system for a family home is proposed, including cost calculation, return on investment and comparison with a common heating system.
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Conversion efficiency of various means of electricity production from solar radiation
Wolf, Juraj ; Tuhovčák, Ján (referee) ; Charvát, Pavel (advisor)
The subject of bachelor thesis contains various methods of converting solar energy to electricity. This study analyzes their conversion efficiencies, potential growth and versatility. Considered technologies are photovoltaic and concentration solar system. Thesis reviews new trends for enhancing conversion efficiencies for both methods and evaluates their potential for future depending on their achieved efficiency, power output, maintenance requirements, climatic condition and demand for addition equipments needed for their application.
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Application of an anemometric hot-wire probe to the measurement of a velocity field downstream of an automotive ventilation outlet
Šíp, Jan ; Tuhovčák, Ján (referee) ; Lízal, František (advisor)
This diploma thesis deals with the research of the flow in front of the benchmark automotive vent. Using thermoanemometry, the velocity field in the area in front of the vent was measured in detail and the intensity of the turbulence was calculated. Computational fluid dynamics of the air flow from the vent was also performed using the STAR-CCM + program. In addition, the influence of the surrounding surfaces simulating the real environment of the automobile on the air flow from the vent was investigated. The diploma thesis contains the calculation of measurement uncertainty. The purpose of this thesis is to obtain complex data on the velocity field and to use them for validation of Computational fluid dynamics.
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Cooling of a powerful light source
Tulis, Vojtěch ; Tuhovčák, Ján (referee) ; Hejčík, Jiří (advisor)
The diploma thesis is focused on calculating the thermal resistance of the line light source and the design of the cooling system with ideal inlet temperature. The partial aim of the work is in cooperation with CAMEA spol. s r. o. to determine the thermal resistances of the individual parts of the device and propose modifications so that the total thermal resistance and the maximum temperature are within the limits given by the cooperating firm. The main objective is to design a cooling system with all safety features and recommended regulation for economical and reliable operation. Analytical calculations, CFD simulations and real-world testing are used to determine the desired results. A reduction by 30% in thermal resistance of the printed circuit board was achieved, the thermal resistance of the aluminum profile with the cooling channel was determined and its hydraulic properties were calculated. The current cooling system designed by CAMEA spol. s r. o. for less powerful diodes was verified for use in a more powerful system, and a new cooling system was designed for efficient and economical operation in a powerful diode system.
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Energy usage of beer production
Maťa, Jakub ; Tuhovčák, Ján (referee) ; Hejčík, Jiří (advisor)
The bachelor thesis deals with the issue of energy consumption of beer production. The first part focuses on the technology of beer production itself, the understanding of which is a key prerequisite for assessing the possibility of using a heat pump for this process. The main part then describes the individual processes and their energy consumption. Finally, it evaluates the use of a heat pump and shows if it could reduce the energy requirements of beer production.
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CFD simulation of refrigerant flow inside the semihermetic compressor
Tuhovčák, Ján ; Knotek, Stanislav (referee) ; Katolický, Jaroslav (advisor)
The CFD simulation of cooling piston compressor Stream, manufactured by Emerson company, is the topic of this diploma thesis. Analysis of moving parts (piston, valves) and refrigerant or physical settings for simulation were based on experimental data provided by Emerson. The goal of the thesis is to test opportunities of Star-CCM+ in simulating the flow inside the compressor. In the end there will be a comparison of experimental data and results from the simulation. The thesis also contains a theoretical background of piston compressors and phenomenon following the operating compressor.
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Determination of heat transfer coefficients from the surface of the thermal manikin
Fojtlín, Miloš ; Tuhovčák, Ján (referee) ; Fišer, Jan (advisor)
This thesis deals with an experimental determination of heat transfer coefficients from the surface of the thermal manikin. The main focus of the work lies on separating radiative and convective heat fluxes from the surface of the thermal manikin. Both nude and clothed, standing and seated postures were investigated respectively. The tests were conducted in a constant air temperature (cca 24°C) and a constant wind speed (cca 0,05 m.s-1) environment. The major part of the radiative heat flux was eliminated by a low emissivity coating applied to the surface of the nude thermal manikin, and in the case of clothed manikin by a low emissivity two-piece dress. Favorable results were achieved only in the case of the nude manikin measurements. The measurements were performed across 34 zones that logically represent parts of a human body. Experimental work confirms theoretical expectations in the means of a heat transfer. In addition, the results of this work were compared to results of a similar experimental work. The outcomes of this thesis provide essential information in order to create detailed computational models of a thermal environment. Such models require anatomically specific, separate values of convective and radiative heat transfer coefficients.
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Compressors in cooling circuits
Řehánek, Matěj ; Hejčík, Jiří (referee) ; Tuhovčák, Ján (advisor)
The bachelor work focuses on carrying out a search of compressors in cooling circuits. This work describes the functions of individual types of the compressors and main advantages and disadvantages are listed there. These facts are then implemented in a mutual comparison and evaluation of efficiency of the compressors.
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Gray water heat exchangers
Devečka, Viktor ; Tuhovčák, Ján (referee) ; Fišer, Jan (advisor)
In the present development of building industry and increasing demands for convenience and comfort of living, energy demands of buildings are also getting higher. After heating, the second largest costs are for the production of hot water. Use of hot water produces grey water with high residual thermal energy, which is drained into sewage. The heat recovery system of grey water solves this heat loss problem. This paper deals with the possibilities of using the heat of grey water. It is aimed mainly at the use of heat energy from grey water to reduce the cost of preparation of hot water. The paper analyzed the energy consumption in buildings. Subsequently, it focuses on the methods of using heat from grey water. It familiarizes with the methods of thermal energy recovery and describes drain water heat recovery system. Drain water heat recovery systems' producers from Czech and Slovak market are named. In conclusion, there are two modeling studies evaluating heat recovery system's efficiency.
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