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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Quantification, the link to relate climate-induced damage to indoor environments in historic buildings

Bylund Melin, Charlotte, Legnér, Mattias January 2013 (has links)
This paper describes and applies a method to quantify and related damage of painted wooden pulpits in 16 churches in Gotland, Sweden, to both the current and the historical indoor climate of the twentieth century. In addition, it demonstrates that the energy used to heat a church in the past can be measured and the study alsopoints towards a relationship between damage and heat output. The results suggest that more damage is present in churches with a higher heat output and there is increased damage in churches using background heating compared to churches that do not. However, the method needs to be improved and a larger population is required to validate these results. / Climate for Culture / Cultural heritage and human comfort: the issue of indoor climate in historic buildings in the twentieth cnentury
2

Development of a stove to meet the new environmental requirements

Pedrosa, Ane January 2018 (has links)
No description available.
3

Vliv zanášení svazku trubek v kotli na jeho životnost / The effect of boiler tube bundle fouling on its service life

Volná, Kateřina January 2018 (has links)
Fouling of tube bundles in boilers on the flue gas side affects not only the service life, but also the boiler heat output and increases maintenance and operating costs. Therefore, it is necessary to minimize or completely eliminate this process. This thesis focuses on comparison of the service life and the heat output of the tube bundles with and without deposit in the coal fired boiler. Simulations of flue gas flow in area of tube bundles with and without deposit are performed using ANSYS Fluent software, which shows that the surface of tube bundles with deposit is much less heated than the surface without deposit. The thermal loads of tubes obtained by the CFD analysis are applied to the model, which is created in the program ANSYS Mechanical, where the calculation of the temperature field in the cross section of the pipe is realized. The effect of fouling on creep life and heat output is then evaluated based on simulation results. The results show that fouling increases creep life, but significantly reduces heat output of heavily fouled tubes. Hence the flue gas flows at a higher temperature to the rest of the tube bundle, and the service life of those tubes will therefore probably decrease.
4

Návrh vytápění rodinného domu. / Design of a space heating system for family house.

Němec, Miloš January 2013 (has links)
The present thesis deals with a design of a heating system for reconstructed family house. The heat loss was calculated according to ČSN EN 12831 Heating systems in buildings – Method for calculation of the heating load. The projected system was regulated. Hot water generation and the safety devices, such as safety valve or expansion tank, were designed. The total costs were calculated afterwards.
5

Vzduchem chlazený rozvaděč / Air cooled electrical cabinet

Rusetskyi, Ivan January 2021 (has links)
During the operation of electrical equipment, heat is generated due to internal losses of the equipment. If these devices are located in the switchgear, the heat output of the individual elements adds up and the temperature in the switchboard can rise to values when the reliability of the individual devices decreases. One of the ways to prevent increase the temperature inside the switchgear from rising to critical values is to solve its proper ventilation (cooling with ambient air). By natural convection or using a ventilator. This diploma thesis deals with the most reliable way of cooling UniGear ZS1 switcgears by natural convection.
6

Tlakové ztráty a tepelný výkon hydraulických kostek lineární integrované hydraulické jednotky / Pressure losses and heat output of the hydraulic blocks of a linear integrated hydraulic unit

Soukup, Lubomír January 2012 (has links)
A common problem in the design of hydraulic systems is the pressure losses caused by movement of viscous liquid in individual elements of hydraulic circuits. These losses have negative effects on the overall efficiency of hydraulic systems and thus their overall operation. There is a change in temperature of working fluid and components (elements) of circuit due to the result of the mentioned losses. This master thesis is focused on the heat generation (output) in hydraulic cubes of a linear integrated hydraulic cubes (here in after LIHJ) which is the prototype of hydraulic lifting equipment. Losses, arising during the operation LIHJ in pipes and in hoses, can be determined numerically and experimentally. Most of hydrostatic transmitters and others hydraulic components are almost always supplied with the necessary documentation which contains all the necessary information such as experimental characteristics, etc. However problematic parts are the hydraulic blocks which are specific to their size and function. Of course, each manufacturer must prepare technical documentation including characteristics which are important for trouble-free operation of the hydraulic system. The main aim of this work is to determine pressure losses and the heat generation (output) in the hydraulics blocks by program which is used for creating geometry and computing using software like Ansys Fluent, which is based on the finite element method. If these calculations could be compared with experimental measurement technically, then heat generation (output) in both the cubes will be evaluated towards other hydraulic components and the whole system (device). The simulation results will be implemented in software which is used for calculation of heat generation in LIHJ at different operating modes and loads. Furthermore, these results will be the basis for the design of geometry of hydraulic blocks with low pressure losses which will reduce energy consumption of the device. At the end of this thesis, some advanced methods for the manufacturing of hydraulic blocks are briefly introduced, namely the method 3-D casting.
7

Att bygga energisnålt med olika ventilationssystem / To build energy efficient with various ventilation systems

Bengtsdottir, Fanney, Hagerup Norrman, Christel January 2018 (has links)
Ett ventilationssystem i en byggnad ska tillföra en tillräcklig mängd frisk luft och skapa ett undertryck för att minska fuktrelaterade problem. Idag finns flera typer av ventilationssystem tillgängliga, några med värmeåtervinning, vilka bidrar med olika funktioner och begränsningar. Studien undersöker skillnaden mellan frånluftsventilation (F), frånluftsvärmepump (FVP) samt fläktstyrt till- och frånluftssystem med roterande återvinning (FTX) i NNE-hus. Tre enfamiljshus i Kronobergs län blev strategiskt utvalda för insamling av data, mätningar, intervjuer och beräkningar. Därefter gjordes en utvärdering och jämförelse mellan systemens prestanda med avseende på termisk komfort, luftomsättning, effektbehov, energianvändning och kostnader. Resultaten visar att kriterierna för termisk komfort uppfylls i samtliga hus under tiden för undersökningar och den specifika energiförbrukningen för de olika husen är mindre än hälften av det maximalt tillåtna. El- och värmeeffektbehovet är minst för F-systemet enligt resultaten men FVP är mest lönsam med hänsyn till återvinning. FVP är även mest lönsam med avseende på ackumulerade kostnader. Resultaten är begränsade för ett specifikt uteklimat under perioden för undersökningen. För en större översikt och tillförlitlighet i beräkningar rekommenderas studier som sträcker sig över ett år. / A ventilation system in a building provides sufficient amount of fresh air and create a negative pressure to reduce moisture-related problems. Today several ventilation systems, some with different energy recovery, are available and those inherence different features and limitations. This study examines differences between exhaust air ventilation without heat recovery (F), exhaust air heat pump (FVP) and exhaust and supply air ventilation with a rotating heat exchanger (FTX) in nearly zero-energy houses. Three single-family houses in Kronoberg County were strategically chosen for the data collection, measurements, interviews and calculations to evaluate and compare their system’s performances in terms of thermal comfort, air circulation, heat recovery effects, energy use and financial attractiveness. The results show that the criteria for thermal comfort are satisfied and the specific energy consumption are within the current requirements in all these houses. Under the period of investigation, the house without heat recovery requires minimum quantity of electricity for ventilation system where as the house with FVP is the most energy efficient. Also, the house with an FVP shows to be the most cost-efficient with lowest accumulated costs. The results are limited for a specific outdoor climate during the studied period. Therefore, examinations over a longer term in different contexts are recommended for a more comprehensive view.
8

Aspekty spolehlivosti při posuzování shody výrobků / Aspect of reliability in compatibility evaluation of products

Šenkýř, Michal January 2008 (has links)
The diploma thesis deals with stating the aspects of reliability in product compatibility evaluation, namely with stating result uncertainty in product parameters testing and diagnosis which are imperative for introduction of the product to the market. The practical part of the thesis focuses on stating selected uncertainty in warm-water boilers testing, especially in gas fueled boilers with rated thermal input of max. 70 kW.
9

Systémy vytápění a chlazení v kancelářských provozech / Heating and cooling systems in office operations

Dostál, Petr January 2020 (has links)
The diploma thesis deals with the design of the heating and cooling system, inclu-ding hot water preparation for the administrative part of the production hall. The first part of the thesis briefly discusses the history of heating and cooling of office buildings, legislative requirements and current solutions. The second part contains the design of the entire heating and cooling system with heat pump as a source of heat and cold. The final part of the thesis describes the experimental measure-ment and evaluation of the efficiency of the ice rink source.

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