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Computational model of heat cycle of Stirling engine
Horák, Jiří ; Hejčík, Jiří (referee) ; Jedelský, Jan (advisor)
This Bachelor´s Thesis deals with heat circulation of a Stirling engine according to the Schmidt theory. In the first part of the thesis there is a short view and characteristic of computational methods for Stirling engine and there are also a few computational models illustrations. The second part describes the Schmidt idealization and its process within the program environment. The final part of the thesis is focused on the realization of the optimal parameters design using a computational model as well as on the comparison of theoretical results with real measured value.
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Warm air heating
Brázda, Jan ; Hejčík, Jiří (referee) ; Charvát, Pavel (advisor)
BRÁZDA Jan: Warm air heating The aim of this bachelor thesis is elaboration the different ways of hot air in buildings and then make a comparison with other methods of heating buildings.
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HVAC in a production plant
Černík, Václav ; Hejčík, Jiří (referee) ; Charvát, Pavel (advisor)
This master’s thesis deals with heating and HVAC in production plant ELMET, spol. s r.o. The first part of the thesis concerns reconstruction of the central heating system, which is outdated and unreliable in the time of the writing of the thesis. The second part deals with cooling of mounting of electronics, where technological requirements are not met due to summer overheating. The third part of the thesis concerns ventilation of metalworking hall using waste heat from production machines.
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Smartphones as experimental tools to take measurements in environmental engineering
Bernard, Jan ; Hejčík, Jiří (referee) ; Jedelský, Jan (advisor)
The thesis is focused on the measuring of the physical quantities by the means of smartphones. It gives a list of the sensors which smartphones contain and it briefly describes their function in ordinary use and their use for the measuring not only physical quantities. Sensors of the mechanical quantities are documented in a greater extent. The measurement limits are addressed as well as the information what inaccuracies of measured quantities can be expected. The study also deals with the added devices which help to overcome the limits of inbuilt sensors and by that they make the measurement more accurate. A review of several researches on already made measurements of the mechanical quantities with smartphones is also given. The last part of the study describes an experiment during which six mobile phones with Android system and six applications were tested by measuring a pink noise signal. Two main facts follows from the results. The measurement with a phone calibrated previously cannot be considered as reliable, the errors can be in the rate of tens of decibels. Whereas phones after calibration in the levels range 45 – 85 dB, when the measuring error is linear, can be used for measurement of the noise with the error less than 2 dB.
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R290 heat pump
Toman, Petr ; Pospíšil, Jiří (referee) ; Hejčík, Jiří (advisor)
This diploma thesis deals with design of air-water heat pump which uses natural refrigerant, propane. In the thesis there are mentioned various types of devices using the source of low-potential heat for heating. The main part of the thesis is the design of the heat pump cooling circuit. In this section, individual components are designed, the calculation and comparison of the heating factor for different operating parameters is performed. Finally, the construction of the coolant circuit and the air exchanger is designed.
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Evaluation of functionality of several modifications of ventilation outlet for passenger car cabin
Caletka, Petr ; Hejčík, Jiří (referee) ; Jedelský, Jan (advisor)
This master thesis deals with determination of boundaries of the flow from a benchmark automotive vent (right-front situated – in front of a front passenger) using the smoke visualization. In this thesis is tested a pack of eight different constructional variants which differ among them by the type of deflection grille. The angles of the flow borders are compared to specific directional requirements (defined by ŠKODA AUTO a.s.) and there is evaluated a directability of each of the constructional variant on the bases of these results. The results of experiments show that better directability in vertical plane achieve deflection grilles with horizontal vanes situated closer to orifice of the vent or deflection grilles with higher number of horizontal vanes and lower number of vertical vanes (independently of their location). Directability of the deflection grilles in horizontal plane is analogically better with vertical vanes situated closer to orifice of the vent or with deflection grilles with higher number of vertical vanes and lower number of horizontal vanes (independently of their location).
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Potential of waste heat recuperation in a polyfunctional building
Nagorskyi, Bogdan ; Charvát, Pavel (referee) ; Hejčík, Jiří (advisor)
The thesis deals with the possibilities of heat recovery in air ventilation systems. After a thorough analysis of the problems, the different ways of ventilation with the return of heat are compared even during simultaneous operation of the heating source. The research includes the selection of a suitable ventilation device with heat recovery based on a first investment and operating costs. Subsequently, the selected ventilation device is used for the HVAC project in the housing part of the multifunctional building. The project is created in BIM Revit software.
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Apparatus for measuring the thermal resistance of the gloves
Pelikán, Jakub ; Fišer, Jan (referee) ; Hejčík, Jiří (advisor)
This thesis deals with common problem health protection at work. Namely hand protection during the work in very cold environment. It’s an analysis of materials suitable for apparatus used for measuring the thermal resistance of the gloves. There was analysed a range of materials. Every single sample was tested for heat conductivity and afterwards was assessed the suitability of materials. Heat was generated by electricity. Ocured heat fields was assessed with thermocamera. After performed experiments of carbon fiber we haven’t reached any satisfying results which we could use for manufacturing of this device. On the other hand kapton film has given very interesting results which we would recommend eventually. Kapton film needs to be modify according to the method listed in the conlusion. This thesis gives us a clear overview and inspiration for additional research of this device. It finds it’s place in research facilities and companies manufacturing protective clothing.
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Heating curve calculation
Štěpánek, Jindřich ; Charvát, Pavel (referee) ; Hejčík, Jiří (advisor)
The bachelor thesis examines the question of heating, more precisely heating depending on climatic conditions of the environment in which the heated entity is situated. It summarizes the information necessary for calculating equithermal dependency as well as the information about the types of heat loss of buildings and their calculation. There is also basic information about the heating elements, their types and characteristics. Using all the information, a model calculation of one point weather compensation curve for the chosen reference room is determined. Further, another way how to get the heating curve is mentioned there, its model calculation is done and the advantages and disadvantages of this method are described.
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The flow analysis inside semi-hermetic reciprocating compressor
Bouchal, Patrik ; Hejčík, Jiří (referee) ; Tuhovčák, Ján (advisor)
The topic of this diploma thesis is CFD simulation of flow inside CO2 semi-hermetic reciprocating compressor Stream manufactured by Emerson. The goal of this thesis is to analyze critical points inside the compressor with regard to excessive entrainment of oil by flowing refrigerant by means of CFD simulation using ANSYS CFX. Simulation for both single-phase and two-phase flow is part of the thesis and results from them are analysed.
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