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Advanced Methods for Damage Evaluation of Boiler Tube Bundles
Naď, Martin ; Odstrčil, Miloslav (referee) ; Jůza, Zdeněk (referee) ; Jegla, Zdeněk (advisor)
This thesis is focused on the application of advanced methods for evaluating damage to boiler tubes, specifically temperature related damage. The aim of this work is to develop an improved damage evaluation procedure utilizing capabilities of modern approaches. This work describes various types of industrial boiler damage. The main focus is on the most exposed and often the most damaged parts of boilers, which are tube bundles (for example, superheaters). Equipment damage is undesirable and often leads to leakages or even to the boiler shutting down. Therefore, it is necessary to find the problem as soon as possible and make the required changes to prevent further damage. The damage types are divided into five categories based on the damage mechanism. Temperature has one of the biggest influences on damage and it may cause short-term or long-term overheating in the tube bundles. This type of damage occurs when the designated temperature is exceeded and results in reduced creep life. It is necessary to know the real surface temperature history of the tube bundle to estimate temperature related damage, however this is often not available. Therefore, it is necessary to calculate those temperatures based on the available data (i.e. inlet and outlet temperatures and pressures). This is real challenge due to the combination of complex flows of the working substances (mainly flue gasses) and heat transfer. Considering available data, new approach is proposed in order to obtain information required for residual creep life estimation. In the first step, thermal – hydraulic calculation is performed followed by a thermal load estimation of a superheater tube bundle in a natural gas fired boiler, using CFD simulations. In the next step, the surface temperature is evaluated and used to determine the temperature related damage, specifically the creep life estimation. The life expectancy is in some ways influenced by imperfections, and therefore at the end of this thesis the influence of the oxide layer on the inner side of tube and fouling on outer side of tube is described.
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Design of Cooling system in family house
Jirsová, Tereza ; Šíp, Jan (referee) ; Pech, Ondřej (advisor)
The bachelor thesis is focused on the design of cooling system in family house that is intended for potential building-up. The introductory chapter deals with the most common ways of a cooling systems in a family houses, using mainly split and multi-split air conditioning units and heat pumps. The following chapter shortly describes the family house, its orientation on the land and the parameters of the building structure. In the next chapter, there is calculated the heat load for the living room and also there are the results for the other rooms that should be cooled. In the last chapter there are created two different designs of possible ways of cooling and also the financial costs for purchase, assembly, operation and revisions are compared. The first design deals with the installation of two multi-splits. In the second design, the Samsung TDM heat pump was installed. This heat pump is the first in Europe, that can operate with one outdoor unit A2W and also A2A. At the end of this thesis, there are more detailed results of heat load calculations and drawings of individual designs of cooling.
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Airconditioning for expectoral beds in a hospital building
Snášel, Michal ; Uher, Pavel (referee) ; Rubina, Aleš (advisor)
The topic of this Bachelor thesis is a design of two air handling units for Emergency Room and nearby surroundings in the hospital’s area. The devices are designed to meet the operating, hygienic and functional requirements for internal microclimate. The tasks for these devices are air conditioning, coverage of heat loss, venting the thermal load and moisturizing the air. The theoretical part is focused on air handling units and their parts.
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Bank Air Conditioning
Grbál, Jakub ; Rubinová, Olga (referee) ; Uher, Pavel (advisor)
This bachelor's thesis deals with the designing of air-conditioning in the bank building. In the theoretic part of the work I present the principle of ventilation and air conditioning. My work describes the advantages and disadvantages of the single systems. The result of the calculation part is the design of the optimum air-conditioning system for the drawing of thermal load in the summer period.
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Studying the behavior of high strength concrete at high temperatures
Sovová, Kateřina ; Kirnbauer, tech Johannes (referee) ; Bodnárová, Lenka (advisor)
This master’s thesis is divided into two parts; practical and theoretical. The theoretical part of this study describes the influence of high temperature on concrete structure and chemical, mechanical and physical changes, which take place during the exposure to high temperatures. The thesis also evaluates spalling of concrete and the methods to prevent it, as well as the function of polypropylene and cellulose fibers in the concrete. The practical part deals with design, production and testing of the cement-based concrete with the use of different fibers (polypropylene fibers and cellulose fibers). The properties and the means of applications in high temperatures are also included. The practical part also assesses the influence of high temperature on strength, porosity, visual changes of specimens, changes of surface and degradation of testing specimens due to heat loads according to normative heat curve (ISO 834) and also according to hydrocarbon curve. For clearer arrangement, the experimental tests are divided into two parts and the measured values are evaluated at the end of each part. The conclusion resumes all data obtained by testing and evaluates what is the most suitable formulation. The approach for further research is also discussed.
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Dispersed reinforcement influence on the maturation of polymercement materials
Zaťko, Petr ; Jakubík, Aleš (referee) ; Bydžovský, Jiří (advisor)
The diploma thesis is focused on polymercement materials with dispersed reinforcement. The aim of this work is development of suitable polymercement mixture and monitoring of the impact of dispersed reinforcement on the course of maturation of these materials and physico-mechanical properties. The effect of high temperatures on the properties of the mortar is also examined. Emphasis is placed on the use of alternative resources and byproducts. Mixed binder of cement and slag and admixture of microsilica was used. Recycled cellulose was used as dispersed reinforcement and was compared with commercial polypropylene fibers.
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Optimization of indoor climate in the "open space" office
Vysloužil, Lukáš ; Blasinski, Petr (referee) ; Maurerová, Lenka (advisor)
The main aim of this thesis is design air-conditioning system and optimization of indoor climate by solar shading. In theoretical part I focused on dividing and description off different types of solar shading. In the next part I designed suitable air-conditioning system for the open space office. The last part is first concentrating on the simulation of the indoor climate in software BSim2014. And then on evaulation of the appropriate solar shading system, whick I can use in the building.
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Comparison of dynamic modulus of elasticity repair materials exposed to thermal stress
Munduchová, Markéta ; Jakubík, Aleš (referee) ; Brožovský, Jiří (advisor)
Diploma thesis is composed of theoretical and practical part. In theoretical part there are findings related to structure changes of concrete exposed to high temperatures. Models used to simulate high temperature exposure of concrete are described in this thesis. Evaluation of internal structure damage is appropriate by using non-destructive methods, which determine dynamic modulus of elasticity in compression and tension. These methods includes ultrasonic impulse method and resonation method and therefore research was made of articles contains these methods. In experimental part of diploma thesis the test specimens was made from repair materials from UTHD and commercially produced repair materials. The test specimens were subjected to thermal load: 200, 400, 600, 800 °C. Damage of internal structure was examined by ultrasonic impulse method and resonation method.
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RESEARCH AND DEVELOPMENT COMPOSITE MATERIAL WITH A HIGHER RESISTANCE TO HIGH TEMPERATURES
Válek, Jaroslav ; Durica,, Tibor (referee) ; Kolář,, Karel (referee) ; Sitek,, Libor (referee) ; Bodnárová, Lenka (advisor)
Concrete has many advantageous properties as regards resistance to fire. It is non-flammable and it has a low thermal conductivity. However, concrete structures, which are not designed for resistance against fire, show significant damage after heating. In particular, the explosive flaking with the consequence of weakening the reinforced concrete cross-section and exposing the steel reinforcement to the temperatures higher than critical temperature of reinforcement. There are only a few possible measures of preventing or mitigating the effects temperature load used. Ways of protection can be divided into two systems: active and passive. Active systems are designed to ensure the greatest possible reduction of temperatures the concrete is exposed to. Passive systems directly resist to high temperatures and fire. Design of composition of concrete with the aim of higher resistance to exposition to high temperatures belongs among the passive systems. A part of the work focuses on summary searches of the problems of concrete and reinforced concrete structures exposed to high temperatures and fire. The goal of the work is defining requirements for cement matrix based composite material and its design ensuring the highest possible resistance to high temperatures or direct fire.
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