National Repository of Grey Literature 110 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Refrigeration system with passive evaporator
Carbol, Marek ; Mauder, Tomáš (referee) ; Hejčík, Jiří (advisor)
This thesis is concerned with the design of a heat pump that does not use a ventilator during operation. In the introductory chapter, the functioning and the basic components of this device and other types of heat pumps are described. Properties of some commonly used refrigerants and oils as well as their classifications are stated. Due to the absence of a ventilator, a special heat exchanger was designed to achieve the required heat power. The choice of components in this refrigeration system takes into consideration the efficiency and functionality of the device.
Design of Helium liquefaction cycle
Bártová, Jana ; Kracík, Petr (referee) ; Hejčík, Jiří (advisor)
The present master thesis deals with the technologies for gas liquefaction focused on helium. The first part of the thesis contains a description of the history of liquefaction, production and usage of liquid helium, as well as the principles of liquefaction and cooling cycles. In the following part of the thesis is a detailed model of the liquefaction cycle for which radial-axial turbine wheels were designed. The last part of the thesis contains financial analysis of the suitability of using the expander with eddy current brake and the expander with an electric generator.
Retrofit of heating system in a family house
Doležel, Pavel ; Hejčík, Jiří (referee) ; Charvát, Pavel (advisor)
The master’s thesis deals with the solid-fuel fired furnaces, complying with the new emission legislation, and their application in central heating. The introductory part of the thesis focuses on the theory of solid fuels combustion, pertinent legislation, and various designs of solid-fuel fired furnaces. The main part of the thesis deals with the design of a central heating system for a townhouse with a solid-fuel fired furnace as the primary heat source for central heating. A roof-mounted PV system was considered for solar-assisted domestic hot water heating. The energy performance of the house was evaluated with the use of the degree-day method and also with a detailed computer simulation in TRNSYS. As an appendix, the thesis includes the detailed engineering calculations and the engineering drawings and diagrams of the central heating system.
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.
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.
Ventilation and cooling system for an apartment in block of flats
Uřičář, Filip ; Fišer, Jan (referee) ; Hejčík, Jiří (advisor)
This Master’s Thesis deals with the design of ventilation and cooling of an under roof flat in a tenement building, built in the 1980s, and consists of five main parts. Within the first main part, the thesis is dedicated to the research of the current state of knowledge in the area ofventilation and cooling of residential premises, secondly, there is a detailed description of a particular flat, thirdly, the calculation for the optimal design of ventilation and cooling are made and, in the fourth part, suggested solutions are proposed with the following evaluation of them including the overall summary. The design of ventilation and cooling was carried out according to the design procedures with respect to the relevant standards and optimized to achieve the desired effect with respect to the requirements of the owner of a housing unit. As a solution, the ventilation of a flat by the Jablotron Futura´s ventilating unit and three variants of a flat cooling were proposed. After the evaluation of all cooling variants, the Sinclair´s multisplit system of cooling was chosen as the most suitable one.
Ventilation of the archive
Hudeček, František ; Fišer, Jan (referee) ; Hejčík, Jiří (advisor)
Ventilation systems for depositories have certain specifics. Their main objective is to provide safe environment for preserving unique cultural or other valuable objects that are being stored for extensive time periods. The economical aspect of the operation should be taken into ac-count and the ventilation system adjusted accordingly. This project also incorporates ventila-tion of secondary areas. Ventilation system is subsequently assessed in terms of indoor air quality (CFD simulation) and energetic requirements (program TRNSYS). Air quality in depositories is evaluated using age of air parameter. The qualitative and quanti-tative outcomes are obtained. Possible measures are then suggested to improve the air quality. The objective of energy simulation is to evaluate overall energy required for a year of opera-tion of main air handling units. In addition, estimation of energy requirements for heating and cooling are made for the whole building. The results are compared and more simulations are carried out in order to lower overall energy consumption.
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.
Heat Pumps with Direct Evaporation
Gerát, Mário ; Formánek, Marian (referee) ; Hejčík, Jiří (advisor)
Master thesis is focused on design of ground heat pump with direct evaporation. First part is dedicated to description of heat pump technology, cooling circulation and sources of low-potential heat. Heat pump ground-water, its main components, classification of refridgerant and systems of direct evaporation are all described in the second part. The last part consists of design of each individual component of heat pump and solution of ground heat exchanger for direct evaporation of refridgerant.
Design solution for the control of existing buildings technologies
Neminář, Štěpán ; Drábek, Ivo (referee) ; Hejčík, Jiří (advisor)
This master´s thesis is dealing with designing wireless management system for existing buildings. In the first part there is description of topologies a communication protocols used for wireless automation. Further there are characterized some devices for lighting, heating, ventilation and cooling regulation. These are used for a model network of a building management, where is system OpenHAB also presented. In the next chapter is aprissed specific edifice and its typical operation where is also designed basic and extended solution for it. This part continues with computation of energy consumption in TRNSYS software, that are used to calculate economic return for both variants.

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