National Repository of Grey Literature 9 records found  Search took 0.01 seconds. 
Evaluation of light pipe influence on daylight in buildings
Král, Jakub ; Katunský,, Dušan (referee) ; Plch,, Jiří (referee) ; Mohelníková, Jitka (advisor)
The topic framework of this dissertation is the technology of lighting in buildings using tubular light pipes. For the assessment of these systems, a continuous measurement of daylight was performed on a comparison surface under two different tubular light pipes of similar dimensions for one year. At the same time, data of exterior lighting conditions were recorded. Independently of these measurements, spectral reflectance measurements of the inner surface samples of both light pipe tubes were performed. Furthermore, light simulations were performed in the HOLIGILM program, and the efficiency of direct tube light pipes of various diameters and lengths was evaluated. Finally, an evaluation of electricity consumption savings was also made by replacing the artificial lighting source with a light pipes. The results of measurements and light simulations provided data for the evaluation and designing of tubular light pipes in buildings.
Analysis of influence of a roof construction on indoor thermal stability in summer season
Hofman, Petr ; Katunský,, Dušan (referee) ; Hirš, Jiří (referee) ; Mohelníková, Jitka (advisor)
The design of the building must respect the basic conditions for ensuring thermal comfort in the living space. The thermal comfort is influenced by several factors and one of them are the constructions of the building envelope. This work was focused on investigating influence of roof structures. The goal was to make analysis of influencing the selected modifications of the roof compositions to the thermal stability in the summer formed by experiments and detailed computer simulations. On the basis of these findings were defined suitable modifications. It has been worked out that the maximum indoor air temperature can be reduced by up to 1.5 °C in a suitable way. The cool roofs, thermal inertia and the ventilated air cavity layer have the greatest benefit. When evaluating the return on investment in a roof with high thermal inertia represented by a concrete layer of 100 mm, its return compared to a light roof and airconditioning is 12.1 years. The return on installation of external blinds on roof windows is 3.3 years compared to airconditioning.
Light Guide Evaluation
Omishore, Ayodeji ; Katunský,, Dušan (referee) ; Darula,, Stanislav (referee) ; Mohelníková, Jitka (advisor)
Light guide is a tubular skylight with mirrored internal surface. It is a lighting device bringing daylight into the interior of a building without windows or into rooms with insufficient daylight. It presents the potential for energy savings, opens the possibility to use places that are not well lit and offers opportunities for improving the visual comfort of the indoor environment. This thesis reviews the potential of light guide system as a daylighting approach in building and presents results of experiments on performance of tubular skylight prototype. The main task of the thesis is focused on comparison of traditional light guide system and newly developed prototype, examination of its light transmittance and efficiency as well as its thermal behaviour in order to find possible improvements for applications in buildings.
Mathematical simulation of temperature profile in the subsoil and creation of a model corresponding its real state
Charvátová, Pavlína ; Katunský,, Dušan (referee) ; Ostrý, Milan (referee) ; Čupr, Karel (advisor)
Increasing demands for low heat losses and energy intensity of a building influence energy calculations. Higher demands are placed on the accuracy of the calculations. An important part of the thermal engineering calculations is the determination of the correct boundary conditions. An important input factor is primarily the indoor and outdoor environment, and temperature is the most important parameter for these types of enviromnent. It is not always the temperature of the external environment, but the environment that is adjacent to the soil or to unheated or differently heated spaces. The possibilities of modeling temperatures below the object are described in the standard ČSN EN ISO 10211. This standard specifies details for a geometric model for the numerical calculation of heat flows to assess the total heat loss of buildings or parts thereof, as well as to derive linear and point heat transfer factors. Furthermore, to calculate minimum surface temperatures to assess the risk of surface condensation and to determine the surface temperature factors. These are two different computational models. Therefore, it would be appropriate to simplify these calculations by simplifying the boundary conditions, namely to conduct an isotherm at a certain level below the terrain, which will be considered as a boundary condition, which is also based on long-term experience with "frost-free" depth. This calculation would be unambiguous, clear and simple.
The influence of internal thermal storage mass used in passive houses' construction systems on their summer thermal stability
Němeček, Martin ; Hraška,, Jozef (referee) ; Katunský,, Dušan (referee) ; Kalousek, Miloš (advisor)
In recent years we may observe a growth in construction of passive houses and low energy houses using lightweight constructions such as modern wooden houses. It is assumed that wooden houses keep overheating more comparing to brick houses during summer period. Due to the lack of research in this field the paper investigates the influence of internal thermal storage mass in passive houses constructions on their summer thermal stability under the Czech climatic conditions. Only sensible heat accumulation without a usage of phase change materials is examined. Differences between wooden houses comparing to brick-built houses are emphasized. Objects of research are mostly residential passive houses in low energy building standards. However, the results of research might be applied to different types of buildings as well. The first section outlines theoretical fundamentals. For the research itself various scientific research methods were used, such as basic mathematical calculations, experimental temperature measurement of two buildings (detached house in Dubňany and in Moravany) and numerical simulations. Own tribute to the research was first of all discussion on the topic of thermal accumulation and structures heat capacity calculation. Experimental measurements outlined conclusive evidence about the importance of internal thermal storage mass in respect of interior summer overheating. The research confirmed that the highest interior temperature reached is mostly influenced by solar gains through unshaded windows. However, the influence of internal thermal storage mass is not remote. If we compare standard timber-framed wooden house to the hole ceramic bricks-built house, the wooden house will overheat by 0,5°C more during a standard day. Wider spread in the maximum temperature reached was measured for lightweight consturctions wooden houses without any internal thermal storage mass. Therefore, such structures should have an additional layer of thermal storage mass.
Optimisation of energy renovation of school buildings
Mocová, Pavla ; Kulhánek,, František (referee) ; Katunský,, Dušan (referee) ; Mohelníková, Jitka (advisor)
The dissertation thesis is focused on a methodology of optimal design energy renovation of school buildings. The thesis is focused on the analysis of selected school buildings during the last 100 years of construction in the first phase. At this phase, are found some important information, especially in terms of the energy performance of the building envelope and results of this parts. Last but not least, CO2 emissions were detected. In the next part of this work, one selected school is assessed in terms of the quality of the environment, due to the evaluation of microbial microclimate on building structures, CO2 concentration and daylight. CO2 concentration and classroom daylight is addressed both for the original and for the new state. Another point of this thesis is the appreciation of the size of the classrooms in the schools both in terms of typological principles and in terms of the average size of classrooms. The daylight assessment is performed on these selected sizes, which is a part of the "PaMo I" design tool. In the next phase of the dissertation was created the design tool "PaMo I". This tool solves the evaluation of the renovation of school buildings from the point of view of the thermal engineering in connection with the influence of the daylight illumination on the classrooms of the school buildings by the thickness of the insulation system and the replacement of the windows. Part of the design tool is also the financial quantification of the investment, the payback period and the impact on the environment of the individual variants. The choice of variant options has been used when making a design tool user decision. The result of this work is a design tool which will help in deciding and finding the optimal alternative to the energy renovation of a school building in connection with daylighting inside classrooms.
Night Cooling in Condition of Czech Republic
Šíma, Jiří ; Katunský,, Dušan (referee) ; Plášek, Josef (referee) ; Šikula, Ondřej (advisor)
The PhD thesis deals with the theoretical evaluation of the potential use of night cooling techniques in condition of the Czech Republic. Mainly aims to evaluate the potential of night cooling, which uses the physical phenomenon of radiation against the night sky. This technique is widely used mainly in the dry and hot regions where there are the most suitable climatic conditions for this cooling method. The work is based on the current state of knowledge in the area of passive and low-energy cooling systems. These knowledges are applied to the conditions of Czech Republic and by using simulations of the energy, behaviour of the buildings explores the benefits in terms of improving of the internal microclimate and from the perspective of economy operation of conventional cooling equipment. In order to establish the benefits of night cooling on the operation of the building in the dynamically changing conditions, the modular simulation program TRNSYS was used, which is suitable for the analysis of energy systems of buildings and their behaviour. The results of simulation results were converted to thermal comfort parameters of the PMV and the PPD.
Experimental drying and desalination of bricks, sandstones and masonry under an applied electric field
Matyščák, Ondřej ; Katunský,, Dušan (referee) ; Ostrý, Milan (referee) ; Doc.Ing. Karel Kubečka, Ph.D (referee) ; Novotný, Miloslav (advisor)
Dewatering and desalination of building constructions is currently a discussed topic. At the present time, different techniques for dewatering and desalination can be used. The existing methods are efficient but it is necessary to improve these methods and to develop new ones. The moisture in the building constructions is directly connected with the salts, which can be dissolved in it and together with the moisture further to move. The salts can cause damage of constructions and change mechanical and physical properties of the buildings materials. The basic demands for dewatering and desalination are the speed, efficiency and economical factors. Presented dissertation focuses on dewatering and desalination with the use of electrokinetic methods together with the technique of the clay poultices. In the first part of the thesis, basic theoretical principles of moisture and salts are described. In the second part (experimental part), the series of experimental measurements were conducted both in the laboratory and in situ. In this part of dissertation, I was dewatering and desalinating bricks and sandstones under an applied electric field. The main focus was on the optimization of a laboratory setup in order to get the highest efficiency for dewatering and desalination. Other measurements were done in situ, where the same technique was used.
PREDICTION SOUND INSULATION PROPERTIES DIVIDER BUILDING STRUCTURES AND SECURITY ACOUSTIC COMFORT INSIDE BUILDINGS
Berková, Petra ; Katunský,, Dušan (referee) ; Tuza,, Karel (referee) ; Vaňková,, Marie (referee) ; Vlček, Milan (advisor)
This thesis deals with the properties of soundproof partition structures in the low-frequency sound at impact sound insulation and security of acoustic comfort inside buildings. The prediction of impact sound is a simulation laboratory measurements of impact sound. The work is based on the occurrence of frequent complaints of inhabitants of residential homes for subjectively poor impact sound insulation of horizontal dividing structures, whose top layer is formed laminate. Although these structures conform in terms of impact sound insulation in accordance with the requirements of CSN 73 0532: 2010, residents complain about the subjective perception of the sounds of lower frequencies. A noise with a distinctive character of sound at low frequencies has been proved by measuring the spectral analysis and evaluation of sound pressure levels caused by the movement of persons roof construction to the floor. On the measurement and evaluation carried out in accordance with the measurement and evaluation of noise in non-working environment can be related requirement under the Regulation No. 272/2011 Coll. "On the protection of health from the adverse effects of noise and vibration." Occupational noise limits for protected buildings interior space do not apply to noise from ordinary use of the apartment. Under current legislation, the problem is in the Czech Republic at present insoluble. Therefore, this work explores ways evaluation of impact sound and delivery is determined conclusions. With the low-frequency impact sound insulation is also related to the latter part of this dissertation, where the computing program ANSYS (version 14.0) is simulated laboratory measurements of impact sound insulation of the real structure. The paper presents the results of simulation, and the sound pressure level in the receiving room to třetinooktávového band 630 Hz. These results are compared with measured values modeled in the laboratory.

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