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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

Characterizing Water as Gap Fill for Double Glazing Units

Adu, Bright 01 May 2015 (has links)
The use of sunlight has always been a major goal in the design and operation of commercial buildings to minimize electrical consumption of artificial lighting systems. Glazing systems designed to allow optimal visible light transmission also allow significant unwanted direct solar heat gain caused by infrared light. Conversely, glazing systems that are designed to reflect unwanted direct solar heat gain significantly reduce the transmittance of visible light through windows. The goal of this research was to characterize the performance of water as gap-fill for double-glazing units in eliminating the compromises that exist in current glazing systems with respect to light and heat transmittance. An in situ test approach and computer simulations were conducted to measure the performance of water-filled glazing units against air-filled glazing units. The thermal transmittance and solar heat gain coefficient values obtained from both the field experiments and computer simulations, glazing units with air-fill proved better than the glazing units with non-flowing water-fill. However, the high convective coefficient and the high thermal mass of the water can be used to its advantage when it is allowed to flow at peak temperatures, thus, maintaining lower temperature swings indoor. This can lead to a reduction of about 50-70% direct solar heat and still maintain high visibility.
2

QUANTIFICATION OF THERMAL BRIDGING EFFECTS IN COLD-FORMED STEEL WALL ASSEMBLIES

Kapoor, Divyansh 08 April 2020 (has links)
Thermal bridging can be defined as the phenomenon where a structural element spanning the building envelope acts like a thermal pathway which collects and moves energy (heat) from the interior to the exterior of the structure. CFS construction, due to the high thermal conductivity of steel with respect to its surrounding structural components and repetitive nature of framing, is highly prone to thermal bridging. Thermal bridging significantly alters the thermal performance of wall assemblies. Hence, the objective of this research project was to quantify the magnitude of energy loss through cold-formed steel (CFS) stud wall assemblies at a component level to lay the groundwork for future works that promote sustainable, energy-efficient, and improved building design recommendations. Therefore, a parametric evaluation was performed using ISO 10211:2007, Annex A, conforming heat transfer software Blocon Heat3 version 8 to generate the data required for analysis. 80 unique wall assemblies and the impact of selected parameters on the overall thermal transmittance of the wall assembly were studied as part of the parametric evaluation. The key variables of the study are steel thickness, stud depth, stud spacing, cavity insulation R-value, external insulation thickness (R-value), and fastener diameter and length. Based on the results of the analysis, effects of increasing stud and track thickness, depth, and stud spacing have been discussed in the form of trends in overall heat flow and linear thermal transmittance coefficient values. Additionaly, effects of increasing external insulation have been discussed by addressing changes in heat flow.
3

Možnosti energetických úspor v bytovém domě Merhautova / Possibilities of energy savings in the residential house Merhautova

Bartek, Čeněk January 2018 (has links)
The diploma thesis is about the reduction of the energy intensity of the existing residential house Merhautova. The design documentation is focused on the thermal insulation of the living area, the replacement of windows and doors according to the variant of the design, accessible entrance to the house, loggia on the south side of the building and the replacement of the roofing. At the beginning of the diploma thesis the experimental part of the thermography was performed. Images of the existing object by the thermal camera were taken and building survey for the design documentation of the current state of the building was performed. Within the theoretical calculations the energy performance certificate was processed in options of the entering the thermal bridges. The energy performance certificate with thermal bridges calculated according to the details was compared with the energy performance certificate with estimated thermal bridges. A comparison of two options of the replacement of windows and doors was made in realation of the energy intesity of the building. A preliminary budget of these two options was also calculated with regard to the expected simple return on investment due to the heat saving.
4

Influência das propriedades térmicas da envolvente opaca no desempenho de habitações de interesse social em São Carlos, SP / Influence of the thermal properties of the opaque envelope in the thermal performance of social housing in São Carlos, SP

Marques, Tássia Helena Teixeira 22 November 2013 (has links)
O objetivo principal desta pesquisa é analisar a influência da transmitância térmica da envolvente opaca (paredes e coberturas) e de outros parâmetros (cor das superfícies exteriores, ventilação natural e inércia térmica) que interferem no desempenho térmico de edifícios habitacionais de interesse social no clima da cidade de São Carlos, SP. Após levantamento de dados em construtoras e em órgãos públicos e privados ligados à habitações, foi selecionado um modelo unifamiliar térreo representativo desta tipologia para a análise. Como a pesquisa baseia-se em simulações paramétricas de desempenho térmico, inicialmente é feito um estudo sobre padrões de modelagem de habitações, identificando quais elementos são mais relevantes. Definidos os parâmetros da modelagem, procede-se à verificação dos valores máximos de propriedades da envoltória prescritos na norma NBR 15575 - Edificações habitacionais - Desempenho, e no regulamento RTQ-R: Regulamento técnico da qualidade para o nível de eficiência energética em edificações residenciais. Esta análise fornece indícios sobre a dificuldade em fixar valores desta propriedade para o fechamento opaco, uma vez que seu desempenho é definido pelas características da envoltória como um todo. Por fim, são realizadas três séries de simulações paramétricas, variando-se a transmitância térmica de paredes e coberturas, a inércia das paredes externas, as cores das superfícies expostas à radiação solar, o aproveitamento de ventilação natural e o uso de cargas internas (ocupação, iluminação e equipamentos). De acordo com os resultados, verifica-se que os melhores desempenhos térmicos estão associados a baixos valores de transmitância da envoltória opaca das habitações. Contudo, percebe-se que as faixas de valores tornam-se muito tênues quando analisa-se o desempenho conjunto dos parâmetros da envoltória. Conclui-se que há uma dificuldade no estabelecimento dos limites de transmitância sem considerar a totalidade de fatores que influem no comportamento térmico da habitação. Isso implica em uma análise conjunta dos materiais de paredes e coberturas e das cores das superfícies exteriores (transmitância, capacidade térmica e absortância). Além disso, critérios que considerem períodos de verão e inverno de acordo com predominância no clima da cidade e ainda outras características, como porcentagem de área envidraçada por orientação de fachada, devem ser considerados nas análises. / The main objective of this research is to analyze the influence of the thermal transmittance of the opaque envelope (walls and roof) and other parameters (color of the exterior surfaces, natural ventilation and thermal mass) that affect the thermal performance of social housing in the city of São Carlos, SP. After a research in public and private agencies related to housing construction, a single-family model was selected for the studies. First, it was carried out a study on parameters of the simulation models, identifying which elements are most relevant for the software. Defined the parameters of the models, it was made a verification of maximum values of properties of the envelope prescribed in the standard NBR 15575 - Residential Buildings - Performance and in the regulation RTQ -R: Technical Regulation for the quality level of energy efficiency in residential buildings. This analysis provides evidence of the difficulty of setting values of this property (U-value) for the opaque envelope, since its performance is defined by the thermal characteristics of the envelope as a whole. Finally, it was made three series of parametric simulations varying the thermal transmittance of walls and roofs, the thermal inertia of the external walls, the colors of the surfaces exposed to solar radiation, the use of natural ventilation and the use of internal loads (occupancy, lighting and equipment). The results indicate that the best performances are associated with low thermal transmittance of the opaque envelope of housing. However, it is clear that the ranges of transmittance values become very tenuous when we analyze the performance of all parameters of the envelope. We conclude that to establish limits of transmittance values results is an incomplete analysis of the thermal performance of the building. It is necessary to consider all factors that influence the thermal behavior of housing, which involves the analysis of the materials of walls and roofs and the colors of exterior surfaces. It is also important to adopt different criteria to consider summer and winter according to predominance in the climate of the city, and to consider in the analysis the percentage of glass area of the exterior envelope.
5

Influência das propriedades térmicas da envolvente opaca no desempenho de habitações de interesse social em São Carlos, SP / Influence of the thermal properties of the opaque envelope in the thermal performance of social housing in São Carlos, SP

Tássia Helena Teixeira Marques 22 November 2013 (has links)
O objetivo principal desta pesquisa é analisar a influência da transmitância térmica da envolvente opaca (paredes e coberturas) e de outros parâmetros (cor das superfícies exteriores, ventilação natural e inércia térmica) que interferem no desempenho térmico de edifícios habitacionais de interesse social no clima da cidade de São Carlos, SP. Após levantamento de dados em construtoras e em órgãos públicos e privados ligados à habitações, foi selecionado um modelo unifamiliar térreo representativo desta tipologia para a análise. Como a pesquisa baseia-se em simulações paramétricas de desempenho térmico, inicialmente é feito um estudo sobre padrões de modelagem de habitações, identificando quais elementos são mais relevantes. Definidos os parâmetros da modelagem, procede-se à verificação dos valores máximos de propriedades da envoltória prescritos na norma NBR 15575 - Edificações habitacionais - Desempenho, e no regulamento RTQ-R: Regulamento técnico da qualidade para o nível de eficiência energética em edificações residenciais. Esta análise fornece indícios sobre a dificuldade em fixar valores desta propriedade para o fechamento opaco, uma vez que seu desempenho é definido pelas características da envoltória como um todo. Por fim, são realizadas três séries de simulações paramétricas, variando-se a transmitância térmica de paredes e coberturas, a inércia das paredes externas, as cores das superfícies expostas à radiação solar, o aproveitamento de ventilação natural e o uso de cargas internas (ocupação, iluminação e equipamentos). De acordo com os resultados, verifica-se que os melhores desempenhos térmicos estão associados a baixos valores de transmitância da envoltória opaca das habitações. Contudo, percebe-se que as faixas de valores tornam-se muito tênues quando analisa-se o desempenho conjunto dos parâmetros da envoltória. Conclui-se que há uma dificuldade no estabelecimento dos limites de transmitância sem considerar a totalidade de fatores que influem no comportamento térmico da habitação. Isso implica em uma análise conjunta dos materiais de paredes e coberturas e das cores das superfícies exteriores (transmitância, capacidade térmica e absortância). Além disso, critérios que considerem períodos de verão e inverno de acordo com predominância no clima da cidade e ainda outras características, como porcentagem de área envidraçada por orientação de fachada, devem ser considerados nas análises. / The main objective of this research is to analyze the influence of the thermal transmittance of the opaque envelope (walls and roof) and other parameters (color of the exterior surfaces, natural ventilation and thermal mass) that affect the thermal performance of social housing in the city of São Carlos, SP. After a research in public and private agencies related to housing construction, a single-family model was selected for the studies. First, it was carried out a study on parameters of the simulation models, identifying which elements are most relevant for the software. Defined the parameters of the models, it was made a verification of maximum values of properties of the envelope prescribed in the standard NBR 15575 - Residential Buildings - Performance and in the regulation RTQ -R: Technical Regulation for the quality level of energy efficiency in residential buildings. This analysis provides evidence of the difficulty of setting values of this property (U-value) for the opaque envelope, since its performance is defined by the thermal characteristics of the envelope as a whole. Finally, it was made three series of parametric simulations varying the thermal transmittance of walls and roofs, the thermal inertia of the external walls, the colors of the surfaces exposed to solar radiation, the use of natural ventilation and the use of internal loads (occupancy, lighting and equipment). The results indicate that the best performances are associated with low thermal transmittance of the opaque envelope of housing. However, it is clear that the ranges of transmittance values become very tenuous when we analyze the performance of all parameters of the envelope. We conclude that to establish limits of transmittance values results is an incomplete analysis of the thermal performance of the building. It is necessary to consider all factors that influence the thermal behavior of housing, which involves the analysis of the materials of walls and roofs and the colors of exterior surfaces. It is also important to adopt different criteria to consider summer and winter according to predominance in the climate of the city, and to consider in the analysis the percentage of glass area of the exterior envelope.
6

Hodnocení konstrukčních detailů budov z pohledu energetické náročnosti / Construction details of buildings evaluation from energy demand point of view

Císař, Milan January 2018 (has links)
Theoretical part of Diploma thesis deals with issues about thermal bridges and thermal connections in building structures. The Calculating part focused on the family houses with a low heat use. The results of this part are energy and financial evaluations of family house. The last part deals with the using of computer technology in engineering practice. These chapters devote about computer modeling an assembly details of passive house and family house after reconstruction (the dates of family house after reconstruction are compared with the results from experimental measurements). The last section of this Diploma thesis solves dynamic modelling of particular passive house in simulation program called Trnsys.
7

Effective Thermal Resistance of Commercial Buildings Using Data Analysis of Whole-Building Electricity Data

Wang, Tian 04 June 2020 (has links)
No description available.
8

Robust and Durable Vacuum Insulation Technology for Buildings

Karami, Peyman January 2015 (has links)
Today’s buildings are responsible for 40% of the world’s energy use and also a substantial share of the Global Warming Potential (GWP). In Sweden, about 21% of the energy use can be related to the heat losses through the climatic envelope. The “Million Program” (Swedish: Miljonprogrammet) is a common name for about one million housing units, erected between 1965 and 1974 and many of these buildings suffer from poor energy performance. An important aim of this study was to access the possibilities of using Vacuum Insulation Panels (VIPs) in buildings with emphasis on the use of VIPs for improving the thermal efficiency of the “Million Program” buildings. The VIPs have a thermal resistance of about 8-10 times better than conventional insulations and offer unique opportunities to reduce the thickness of the thermal insulation. This thesis is divided into three main subjects. The first subject aims to investigate new alternative VIP cores that may reduce the market price of VIPs. Three newly developed nanoporous silica were tested using different steady-state and transient methods. A new self-designed device, connected to a Transient Plane Source (TPS) instrument was used to determine the thermal conductivity of granular powders at different gaseous pressure combined with different mechanical loads. The conclusion was that the TPS technique is less suitable for conducting thermal conductivity measurements on low-density nanoporous silica powders. However, deviations in the results are minimal for densities above a limit at which the pure conduction becomes dominant compared to heat transfer by radiation. The second subject of this work was to propose a new and robust VIP mounting system, with minimized thermal bridges, for improving the thermal efficiency of the “Million Program” buildings. On the basis of the parametric analysis and dynamic simulations, a new VIP mounting system was proposed and evaluated through full scale measurements in a climatic chamber. The in situ measurements showed that the suggested new VIP technical solution, consisting of 20mm thick VIPs, can improve the thermal transmittance of the wall, up to a level of 56%. An improved thermal transmittance of the wall at centre-of-panel coordinate of 0.118 to 0.132 W m-2K-1 and a measured centre-of-panel thermal conductivity (λcentre-of-panel) of 7 mW m-1K-1 were reached. Furthermore, this thesis includes a new approach to measure the thermal bridge impacts due to the VIP joints and laminates, through conducting infrared thermography investigations. An effective thermal conductivity of 10.9 mW m-1K-1 was measured. The higher measured centre-of-panel and effective thermal conductivities than the published centre-of-panel thermal conductivity of 4.2 mW m-1K-1 from the VIP manufacturer, suggest that the real thermal performance of VIPs, when are mounted in construction, is comparatively worse than of the measured performance in the laboratory. An effective thermal conductivity of 10.9 mW m-1K-1 will, however, provide an excellent thermal performance to the construction. The third subject of this thesis aims to assess the environmental impacts of production and operation of VIP-insulated buildings, since there is a lack of life cycle analysis of whole buildings with vacuum panels. It was concluded that VIPs have a greater environmental impact than conventional insulation, in all categories except Ozone Depilation Potential. The VIPs have a measurable influence on the total Global Warming Potential and Primary Energy use of the buildings when both production and operation are taken into account. However, the environmental effect of using VIPs is positive when compared to the GWP of a standard building (a reduction of 6%) while the PE is increased by 20%. It was concluded that further promotion of VIPs will benefit from reduced energy use or alternative energy sources in the production of VIP cores while the use of alternative cores and recycling of VIP cores may also help reduce the environmental impact. Also, a sensitivity analysis of this study showed that the choice of VIPs has a significant effect on the environmental impacts, allowing for a reduction of the total PE of a building by 12% and the GWP can be reduced as much as 11% when considering both production and operation of 50 yes. Finally, it’s possible to conclude that the VIPs are very competitive alternative for insulating buildings from the Swedish “Million Program”. Nevertheless, further investigations require for minimizing the measurable environmental impacts that acquired in this LCA study for the VIP-insulated buildings. / Dagens byggnader ansvarar för omkring 40% av världens energianvändning och  står också för en väsentlig del av utsläppen av växthusgaser. I Sverige kan ca 21 % av energianvändningen relateras till förluster genom klimatskalet. Miljonprogrammet är ett namn för omkring en miljon bostäder som byggdes mellan 1965 och 1974, och många av dessa byggnader har en dålig energiprestanda efter dagens mått. Huvudsyftet med denna studie har varit att utforska möjligheterna att använda vakuumisoleringspaneler (VIP:ar) i byggnader med viss fokus på tillämpning i Miljonprogrammets byggnader. Med en värmeledningsförmåga som är ca 8 - 10 gånger bättre än för traditionell isolering erbjuder VIP:arna unika möjligheter till förbättrad termisk prestanda med minimal isolerings tjocklek. Denna avhandling hade tre huvudsyften. Det första var att undersöka nya alternativ för kärnmaterial som bland annat kan reducera kostnaden vid produktion av VIP:ar. Tre nyutvecklade nanoporösa kiselpulver har testats med olika stationära och transienta metoder. En inom projektet utvecklad testbädd som kan anslutas till TPS instrument (Transient Plane Source sensor), har använts för att mäta värmeledningsförmågan hos kärnmaterial för VIP:ar, vid varierande gastryck och olika mekaniska laster. Slutsatsen blev att transienta metoder är mindre lämpliga för utföra mätningar av värmeledningsförmåga för nanoporösa kiselpulver låg densitet. Avvikelsen i resultaten är dock minimal för densiteter ovan en gräns då värmeledningen genom fasta material blir dominerande jämfört med värmeöverföring genom strålning. Det andra syftet har varit att föreslå ett nytt monteringssystem för VIP:ar som kan användas för att förbättra energieffektiviteten i byggnader som är typiska för Miljonprogrammet. Genom parametrisk analys och dynamiska simuleringar har vi kommit fram till ett förslag på ett nytt monteringssystem för VIP:ar som har utvärderats genom fullskaleförsök i klimatkammare. Resultaten från fullskaleförsöken visar att den nya tekniska lösningen förbättrar väggens U-värde med upp till 56 %. En förbättrad värmegenomgångskoefficienten för väggen i mitten av en VIP blev mellan 0.118 till 0,132 W m-2K-1 och värmeledningstalet centre-av-panel 7 mW m-1K-1 uppnåddes. Detta arbete innehåller dessutom en ny metod för att mäta köldbryggor i anslutningar med hjälp av infraröd termografi. En effektiv värmeledningsförmåga för 10.9 mW m-1K-1 uppnåddes. Resultaten tyder även på att den verkliga termiska prestandan av VIP:ar i konstruktioner är något sämre än mätvärden för paneler i laboratorium. En effektiv värmeledningsförmåga av 10.9 mW m-1K-1 ger dock väggkonstruktionen en utmärkt termisk prestanda. Det tredje syftet har varit att bedöma miljöpåverkan av en VIP-isolerad byggnad, från produktion till drift, eftersom en livscykelanalys av hela byggnader som är isolerade med vakuumisoleringspaneler inte har gjorts tidigare. Slutsatsen var att VIP:ar har en större miljöpåverkan än traditionell isolering, i alla kategorier förutom ozonnedbrytande potential. VIP:ar har en mätbar påverkan på de totala utsläppen av växthusgaser och primärenergianvändningen i byggnader när både produktion och drift beaktas. Miljöpåverkan av de använda VIP:arna är dock positiv jämfört med GWP av en standardbyggnad (en minskning med 6 %) medan primärenergianvändningen ökade med 20 %. Slutsatsen var att ytterligare användning av VIP:ar gynnas av reducerad energiförbrukning och alternativa energikällor i produktionen av nanoporösa kiselpulver medan användningen av alternativa kärnmaterial och återvinning av VIP kärnor kan hjälpa till att minska miljöpåverkan. En känslighetsanalys visade att valet av VIP:ar har en betydande inverkan på miljöpåverkan, vilket ger möjlighet att reducera den totala användningen av primärenergi i en byggnad med 12 % och utsläppen av växthusgaser kan vara minska, så mycket som 11 % när det gäller både produktion och drift under 50 år. Avslutningsvis är det möjligt att dra slutsatsen att VIP:ar är ett mycket konkurrenskraftigt alternativ för att isolera byggnader som är typiska för Miljonprogrammet. Dock krävs ytterligare undersökningar för att minimera de mätbara miljöeffekter som förvärvats i denna LCA-studie för VIP-isolerade byggnader. / <p>QC 20151109</p> / Simulations of heat and moisture conditions in a retrofit wall construction with Vacuum Insulation Panels / Textural and thermal conductivity properties of a low density mesoporous silica material / A study of the thermal conductivity of granular silica materials for VIPs at different levels of gaseous pressure and external loads / Evaluation of the thermal conductivity of a new nanoporous silica material for VIPs – trends of thermal conductivity versus density / A comparative study of the environmental impact of Swedish residential buildings with vacuum insulation panels / ETICS with VIPs for improving buildings from the Swedish million unit program “Miljonprogrammet”
9

Tepelně technické vlastnosti rámu okenní výplně a připojovací spáry / Thermal properties of the window frame and the connection joints

Hejný, Lukáš January 2015 (has links)
This thesis deals with the solution problem of fitting a window in the wall, especially for passive houses. It provides options to optimize the window connection joints, improve the thermal transmittance of the window frame, thereby reducing the total heat loss through the window. In the first part of the thesis is a research literature on the windows and heat technical and physical mechanisms. Are described equations and physical processes taking place in the windows and related building structures. This section describes the basic points in history, technical description of windows, etc. and present ways of assembly Installation the window and the influence of the thermal properties of the heat loss. The next part deals with the description of the work and the results obtained in the course of doctoral study. Describes the main objectives of the dissertation thesis, calculations and simulations of temperature fields and the results of the calculated values. Furthermore are described and analyzed measurement data and compared with the calculated values. At the end dissertation thesis are given opportunities to improve the current solution regarding the heat transfer coefficient of the frame, the optimal way of installation fillers windows in the perimeter wall and improve the thermal properties of the connecting joint.
10

Studie snížení energetické náročnosti bytového domu / Study of energy consumption reduction of block of flats

Svoboda, Lukáš January 2014 (has links)
The goal of the thesis is firstly to get all the information about the initial state of solved block of flats, which is located on the street Merhautova 76/954 in Brno – Černá pole, in terms of constructions, energy consumption and initial state of heating system. In the second part of the thesis, where are discussed the possibilities of reduction of energy consumption, variant drafts of reduction of energy consumption and their financial costs and the choice of optimal variant. Third part deals with assement of solved block of flats in terms of sustainable built environment by using tool to rate buildings in terms of sustainable built environment - SBToolCZ, evaluation of possibility to use renewables. In the end are written summaries and recommendations.

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