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Performance simulation of a solar PV system for a single-family home
Veličková, Kateřina ; Hejčík, Jiří (referee) ; Charvát, Pavel (advisor)
Recently, renewable energy resources have become an urgent issue, as a result there are many papers focused on photovoltaic power plants and their performance simulations. These simulations not only allow us to assess the reduction of dependency on the fossil fuels, but also to calculate costs saving. This work considers the operation of a single-family house in the Czech Republic. However, a summary of photovoltaic potential factors is presented as well as the most common applications used for performance simulations of photovoltaic power plants. In practical part of this work, the load profile for common household is determined based on the data provided by the Energy Market Operator, alternatively the load profiles of two households owning a plug-in hybrid are also determined. The performance simulation is assembled in TRNSYS application and the results are summed up in the last chapter.
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The Mpemba effect and its use in applications
Wittek, David ; Hejčík, Jiří (referee) ; Mauder, Tomáš (advisor)
Hot water appears to freeze faster than cold water. Already Aristoteles mentions this seemingly meaningless fact in his writings. However, to this day no one has been able to fully clarify this phenomenon. Work is focused on factors, which may affect the freezing process of liquids. The composition of the experimental set up will be designed to approach the conditions of the pioneer of scientific research on this issue, E. Mpemba. He has obtained the most convincing results confirming existence of the phenomenon. Based on results, it will be discussed possibilities of practical application, for example for saving time during freezing.
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Analysis of thermodynamic cycles of heat pumps
Vendrame, Katia ; Hejčík, Jiří (referee) ; Klimeš, Lubomír (advisor)
This bachelor thesis focuses on heat pumps for residential applications and their functioning. The theoretical part describes components of heat pump and briefly discusses energy sources that can be used. The types of refrigerants, which are currently used in heat pumps, are discussed: except to the broadly used HFC refrigerants, also the use of carbon dioxide is described. Further, the theoretical part includes the theory of thermodynamical cycles used in heat pumps. In the practical part a computer program for a fundamental thermodynamic analysis of heat pumps was created. The functionality and applicability of the program are demonstrated in the solution fo several problems.
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Absorption chiller
Najbrtová, Zuzana ; Bouchal, Patrik (referee) ; Hejčík, Jiří (advisor)
The master thesis on the Absorption chiller is devoted to the dimensioning of the operating points of the absorption chiller cycle. The thesis is based on the required realistic parameter such as cooling capacity, temperature of the chilled fluid and temperature of the driving hot water. The proposed duty cycle is single stage with two heat recovery exchangers, one between weak and rich solution, and the other between liquid and gas refrigerant. The working fluids of this cycle is ammonia and water. The thesis is divided into theoretical and practical parts. The theoretical part summarizes the basic knowledge of absorption cooling, including an explanation of the principle of trigenera-tion in which the proposed unit is to operate. The practical part deals with the actual design and calculation of the operating points, parameters of the secondary working fluids and the performance of the devices themselves. The calculation is compared with the real absorption units and the compressor unit.
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Noise study of heat pump
Gregorovičová, Eva ; Hejčík, Jiří (referee) ; Jedelský, Jan (advisor)
The thesis deals with a noise study of a heat pump, which is important for the assessment of the acoustic comfort of people. The thesis describes the theory of basic terms, quantities, measuring devices and the chosen method of determining sound power. The acoustic properties and technical condition of the measured heat pump, its possible noise sources and the possibilities of reducing their emissions are also described. The total noise level of the device is determined by the intensity probe according to the scanning method according to ČSN ISO 9614-2. Based on the acoustic map and frequency spectrum, the partial noise sources of the heat pump are identified. The resulting values from the measurements are compared with the manufacturer's values. The noise situation is assessed by measuring and comparing the measured values with the hygienic limits. Furthermore, the designs of the noise protection measures are assessed, and the design of the noise protection measures for the specific case is carried out. Finally, possible noise protection measures are implemented and experimentally verified. The results confirm the need for further development of heat pumps to reduce noise emissions.
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3D printer enclosure
Vícha, Daniel ; Pech, Ondřej (referee) ; Hejčík, Jiří (advisor)
This bachelor thesis consists of four main parts. The first part deals with 3D printing methods, and especially the FDM method, for which a box is subsequently designed. The second part mentions suitable 3D printing conditions, which can be influenced by 3D printer modifications. The third part describes the negative external influences affecting the quality and course of printing and the subsequent elimination of these influences. The fourth, main part, deals with designing an enclosure for the 3D printer Prusa i3 MK3s, which will prevent the effects of external influences and improve the print quality. The enclosure is designed to ensure optimal printing conditions, an ideal environment for the filament, and the correct function of multi-material upgrade MMU2/S.
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Refrigeration device for home brewery
Křivánek, František ; Tuhovčák, Ján (referee) ; Hejčík, Jiří (advisor)
This bachelor thesis deals with the issue of cooling processes and the design of cooling equipment for home brewery. The first part outlines an introduction to this issue, followed by the design of the cooling circuit and a description of its individual parts. Attached is the cost estimate for this device.
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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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Dehumidifier
Koštuřík, Adam ; Elcner, Jakub (referee) ; Hejčík, Jiří (advisor)
This bachelor thesis shall inform readers with the theory of humid air and its dehumidification at low temperatures. Here are the basic ways to dehumidify the air and then is selected a device that is suitable for low temperature conditions. Humidity problems in refrigerated areas are also described here.
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Air cooled electrical cabinet
Rusetskyi, Ivan ; Bělka, Miloslav (referee) ; Hejčík, Jiří (advisor)
During the operation of electrical equipment, heat is generated due to internal losses of the equipment. If these devices are located in the switchgear, the heat output of the individual elements adds up and the temperature in the switchboard can rise to values when the reliability of the individual devices decreases. One of the ways to prevent increase the temperature inside the switchgear from rising to critical values is to solve its proper ventilation (cooling with ambient air). By natural convection or using a ventilator. This diploma thesis deals with the most reliable way of cooling UniGear ZS1 switcgears by natural convection.
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