|
| |
|
|
Calculations of steam condensers
Mifek, Roman ; Kilkovský, Bohuslav (referee) ; Jegla, Zdeněk (advisor)
This thesis deals with the calculation procedures for determining the heat transfer coefficient for steam condensers. The first section provides a basic overview for industrial steam condensers and possible procedure for selecting the appropriate type of tube condenser. The next section describes the types of condensation and equations for determining the heat transfer coefficient for various geometries of tubular condensers. In the final section there is performed practical calculation of condenser in Maple software using the above relations. The results obtained in this calculation are compared with the results obtained by professional computational software Chemcad and HTRI.
|
|
|
Influence of Insulating a Building for Family Holiday on the Expenses Related to its Operation
Hanyk, Tomáš ; Hrdlička, Tomáš (referee) ; Čech, Josef (advisor)
This diploma thesis deals with the impact of thermal insulation on expenses relateted to the operation of the weekend house. Theoretical part describes options of thermal insulation systems, insulation methodes, describes structural prices and costs. Practical part of this thesis describes heat costs on specific weekend house situated in Karlovy Vary region. Thermal insulations are designed in three different variants. Calculation of costs of every designed insulation systém is included in this thesis. In next part of thesis is calculated return of investment for every designed solution. In conclusion of the diploma thesis are compared impacts of thermal insulation on expenses ralated to the operation of the weekend house.
|
|
|
Low-energy construction
Halama, Miroslav ; Vaňková, Lucie (referee) ; Krejza, Zdeněk (advisor)
The bachelor thesis is proposing three construct variants of chosen family houses and assign each to particular energy performance certificate of A, B, and C values. Thesis describes trends in low-energy houses and theory of building valuation. Furthermore established financial indicator to determinate approximate building value and calculate investment efficiency and its correlation with operating costs. The aim of this study is economic analysis of investment efficiency of particular energy performance certificate buildings.
|
|
|
Spray Cooling at High Temperatures
Chabičovský, Martin ; Čarnogurská, Mária (referee) ; Hajduk, Daniel (referee) ; Raudenský, Miroslav (advisor)
Spray cooling of hot surfaces is used in the metallurgical industry during continuous casting, hot rolling or heat treatment. The water is sprayed on the cooled surface by the nozzle which transforms the water stream to droplets. The spray cooling of hot surfaces can be characterized as forced convection with the presence of the boiling. This physically complicated process is influenced by many factors, such as impurities and contaminants in the water, water temperature, water flow rate, droplet size, droplet impact velocity, surface temperature, surface roughness or the presence of oxides (scales) on the cooled surface. The dominant factor that affects the heat transfer during the spray cooling is the water impingement density. Other factors have a smaller but also significant effect. This doctoral thesis deals with the influence of the water temperature, surface roughness and the presence of oxides on the intensity of the spray cooling. These factors are investigated by laboratory experiments in which the hot steel surface is spray cooled. Effect of the oxide layer is also investigated by the numerical simulation. The experimental results are theoretically explained and generalized using mathematical methods.
|
|
|
Evaluation of energy consumption of ski lodging house
Moronga, Jozef ; Horák, Petr (referee) ; Maurerová, Lenka (advisor)
Bachelor thesis dealt with the energy rating of ski accommodations. The theoretical part solves the legislation on the energy performance of buildings, energy audits, energy assessment. Computing and practical part includes assessing the energy performance of the calculation of the building energy performance certificate. Furthermore, the proposed austerity measures and selected the best option. To end review of the economic and ecological terms.
|
|
|
The impact of executing new thermal insulation on a apartment building on the expenses associated with its operation
Machová, Petra ; Kosová, Jaroslava (referee) ; Čech, Josef (advisor)
The topic of the diploma thesis „The impact of executing new thermal insulation on a apartment building on the expenses associated with its operation “ is a draft and appraisal of four variants of thermal insulation of the building. The thesis deals with the assessment of the current proposal for apartment building envelopes along with proposing alternative plans with emphasis on reducing heating costs. The first section describes the types of buildings according to heating demand and a list of different variants of thermal insulation materials. The second part is devoted to a specific apartment building in the Ústí nad Labem for which there are designed in four variants of insulation. The work includes thermal assessment in original condition and the assessment of new condition modified by adding thermal insulation. Through research will bedetermined price of implementation of proposed insulation options together with the costs of operation of the apartment building. In conclusion, the diploma thesis evaluates the payback period of insulation.
|
|
|
Quantification of Hydraulic Descaling Mechanisms
Hrabovský, Jozef ; Toman,, Zdeněk (referee) ; Dobeš, Ferdinand (referee) ; Horský, Jaroslav (advisor)
The issue of descaling is an important part of the forging and heat treatment of steel and semi products of steel production. Rising of new information and study of this process can increase efficiency and improve the surface quality after descaling. This thesis is focused on the mechanisms of the high pressure hydraulic descaling qualification and study of the chemical compounds of which the scales grown. To achieve all goals of this work and to get a comprehensive view of descaling process, few experimental measurements and numerical analyses were performed. All experimental measurements were focused on obtaining data about fundamental parameters and effects of the hydraulic descaling. The data obtained from measurements were applied to numerical analyses, which aimed to discover a deeper relation and to confirm the experimental results. This thesis can be divided into two main parts. The first part is devoted to parameters of the water jet study. The main studied characteristics of the high pressure hydraulic water jet were heat transfer coefficient and impact pressure at different modes such as standard or pulsating water jet. Experimentally measured data of these parameters were applied in numerical analyses. The numerical analyses were focused on studying the impact of the water jet parameters on the stresses in the oxide scale layers. A further water jet analysis was focused on the influence of the individual parts of the hydraulic system (such as water chamber or stabilizer) on its characteristics. In this part different types of the water chambers in combination with different types of stabilizers on the impact pressure values were investigated. These measurements were supported by fluid flow analysis through the hydraulic system. The second part of this work was focused on getting mechanical properties of the oxide scales from specimens prepared from standard structural steel and specimens from silicon steel. In this thesis, the influence of various parameters and characteristics was studied on these two types of steel. Mechanical properties of oxide scale structures were carried out by the Small Punch Test method. To obtain the fundamental mechanical properties such as Young´s modulus, yield strength and ultimate strength, material parameters based on the measured data were optimized. The whole work was carried out in order to get valuable and comprehensive results about high pressure hydraulic descaling process and influencing factors as well as about oxide scales themselves.
|
|
|
Heat transfer on sprinkled tube bundle
Copek, Tomáš ; Pospíšil, Jiří (referee) ; Kracík, Petr (advisor)
This bachelor thesis named Heat transfer on sprinkled tube bundle deals with experimental assesment of heat transfer coefficient on sprikled tube bundle. Its goal is to measure, compare and evaluate values and trends of heat transfer coefficient on external surface according to flow rate of cooling water. Evaluation will be focused on size of pitch between tubes, type of tubes surface and influence of temperature gradient. Measurement was ongoing at atmospheric pressure. Warm water flowing in tube bundle is cooled by cold sprinkling water. Tube bundle consists of ten tubes located horizontaly beneath each other with smooth, grooved or sanblasted surface. Distance between tubes vary from 15 to 35 milimetres. Measurement of two temperature gradients 15-40 and 15-45 (15°C is temperature of sprinkling water in distribution tube; 40°C or 45°C is temperature of water entering the tube bundle) is carried out for each pitch and tube surface.
|
|
|
Daily launches steam turbines and their impact on the life of the turbine
Štěpánová, Lenka ; Kracík, Petr (referee) ; Fiedler, Jan (advisor)
This thesis concentrates on the problem of steam turbines, which require daily cycling by reason of an unstable nature of the energy source. The first part focuses on the current trends which have caused still increasing demand for steam turbines designed for every day start-ups. There is a description of the steam turbine start-up procedure and the heat transfer theory thanks to which the list of the critical parts of the steam turbine has been selected and with respect to these critical points has been created the draft of technical measures for the turbine. The thesis is finished with an evaluation of the life of the steam turbine casing as one of the critical parts and with a proposal for a calculation of a start-up time of the steam turbine.
|
guest ::
