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Prediction of interior daylight under clear sky conditionsAlshaibani, Khalid Asker January 1996 (has links)
Most available techniques for predicting internal daylight illuminance do not take into account reflected sunlight, nor the fact that under clear sky conditions the direction of the illuminance is usually upwards, not downwards from the sky. The general goal of this study is to investigate the issue of predicting the internal illuminance from natural light in clear sky conditions. This includes the possibility of proposing a method based on the concept of the average daylight factor for use in sunny climates. This thesis is divided into eight chapters. After introducing the problem in Chapter One, Chapter Two is a literature review of problems associated with utilising natural light in sunny regions. Chapter Three is the statement of the problem and how it will be solved. Existing equations for finding the average daylight factor have one thing in common: they assume that the incident light on the window comes directly from an overcast sky or by external reflection from it. If any of these equations are to be used under clear sky conditions, or a new method is to be developed based on the same concepts, the sensitivity of average internal illuminance to the direction of external light needs to be tested. A study of this is described in Chapter Four. Chapter Five tests, by numerical simulation, the performance of existing average daylight factor methods under clear sky conditions. It is concluded that they are not appropriate for sunny regions. The tests, and the conclusions from Chapter Four, do, however, suggest a new approach. This has two bases. The first is that it has been shown to be possible to relate incident light on the window plane to horizontal sky illuminance, and this sets a minimum condition for window design. In practice this can be used in conjunction with a limiting maximum window size based on heat gain and other environmental issues. The second basis is a new formula for relating average internal illuminance to external window plane illuminance. The overall result is a formula for predicting internal illuminance as a ratio of external horizontal sky iluminance. In Chapter Seven this approach is tested. Two methods are used: field measurements under real sky conditions, and comparison with detailed calculations.
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An examination of the thermophysical nature of solar-control films using an illuminated hot box and computer based simulation modelling techniquesGriffiths, P. W. January 1994 (has links)
Solar-control films are increasingly being retrofitted to the windows of buildings as a means of reducing solar gain. At present, there is a dearth of information concerning how these films effect the thermal comfort of occupants within buildings where these films have been applied. An illuminated hot box, utilising a xenon lamp to simulate sunlight, has been designed as a testing facility. The illuminated hot box has been used to obtain information on how much thermal radiation enters the internal space from a window fitted with a solar-control film. The data from the experimental apparatus was verified using a finite-difference model written on a personal computer, with the aim of the computer program being used to compare different films, and thereby avoiding expensive experiments. The experimental rig produced usable data for the tested films only when the lamp was orthogonal to the plane of the glass, with errors occurring, and increasing, as the angle of incidence between the lamp and the glass increased. This conclusion was verified by the computer based model. It was seen that the illuminated hot box was too small to give accurate measurements for angles of incidence other than 0°. It is suggested that a larger illuminated hot box which is able to eliminate the problems encountered when measuring for angles of incidence above 10° would be desirable. Furthermore, a more complex transient finite-difference computer based simulation model is needed, taking into account the conclusions that were made during this study.
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Desenho de aberturas e comportamento térmico de ambientes de simulação : qualificação e quantificação para região climática de Porto Alegre / Windows Design and Thermal Behavior of Environment: qualification and quantification for climatic region of Porto AlegreZiebell, Clarissa Sartori January 2013 (has links)
O objetivo dessa dissertação foi estudar a relação entre o desenho da abertura e o comportamento térmico de ambientes internos de simulação. Para tanto, o comportamento foi quantificado a partir da energia consumida pelo ar-condicionado para manter o ambiente interno com temperaturas aceitáveis para o conforto térmico. Dessa forma, quanto menor a energia consumida, melhor o comportamento térmico do ambiente. A energia consumida foi obtida através de simulação com o software EnergyPlus 7.0. Os parâmetros investigados foram baseados nas variáveis das equações do RTQ-R (Regulamento Técnico da Qualidade para o Nível de Eficiência Energética das Edificações Residenciais). Para o estudo foram simulados ambientes onde em cada simulação era variada a orientação (norte, nordeste, leste, sudeste, sul, sudoeste, oeste e noroeste) o tamanho (cinco diferentes tamanhos) e a existência ou não de dispositivos de sombreamento das aberturas. Como análise complementar, foi também estudado a influência da intensificação da ventilação durante as noites de verão no comportamento térmico de ambientes. No total, o mesmo ambiente foi simulado 240 vezes. O estudo se concentrou no contexto climático da cidade de Porto Alegre. O foco da pesquisa foi a abertura porque esse elemento de construção, dependendo de seu tamanho em relação à parede, de sua orientação, de sua vedação, ou de outras características, pode permitir uma troca térmica significativa entre o interior e o exterior da edificação, independentemente das características de isolamento das paredes. A relação entre o desenho da abertura e o comportamento térmico de ambientes é discutida tendo como base o RTQ-R, pois esse é o regulamento de classificação do nível de eficiência energética de edificações residenciais vigente no país. Ao final do trabalho, a influência dos parâmetros tamanho, orientação e sombreamento para o comportamento térmico de ambientes é discutida tendo como base os resultados do EnergyPlus 7.0 – ferramenta de quantificação – e do RTQ-R – ferramenta de qualificação. Como resultado das simulações feitas com o EnergyPlus 7.0, obteve-se informação sobre a forma pela qual o tamanho, a orientação e o sombreamento das aberturas influenciam o comportamento térmico de ambientes. As análises feitas com o uso das equações do RTQ-R levaram a resultados de maneira geral compatíveis com as simulações, apesar da menor sensibilidade dessa ferramenta qualitativa. Nas análises com o EnergyPlus 7.0, o tamanho foi a variável que apresentou maior influência. Com o uso do RTQ-R, a variável que se mostrou mais influente foi o sombreamento. Foi observado ainda que as equações do RTQ-R ajudam na definição da orientação, do tamanho e do sombreamento das aberturas, características que são essenciais para aprimorar o comportamento térmico de ambientes. Portanto, o uso das equações como ferramenta de suporte ao desenvolvimento de projetos é recomendável. O EnergyPlus também se mostrou uma ferramenta capaz de auxiliar a escolha das melhores estratégias de projeto. Sendo assim, as duas ferramentas se complementam. / The objective of this dissertation was to demonstrate the relationship between the design of the window and the thermal behavior of simulated internal environments. The thermal behavior was quantified from the energy consumed by the air conditioning system to maintain the internal environment with acceptable temperatures for thermal comfort. Thus, the lower the energy consumed, the better the thermal performance of the internal environment. The amount of energy consumed was obtained by simulation with the software EnergyPlus 7.0. The parameters investigated were based on the variables of the equations of RTQ-R (Quality Technical Regulation for the Level of Energy Efficiency of Residential Buildings). For the study internal environments were simulated, where in each simulation were varied orientation (north, northeast, east, southeast, south, southwest, west and northwest) size (five different sizes) and the presence or absence of shading window devices. As a complement, was also studied the influence of the intensification of ventilation during the summer nights on the thermal behavior of internal environments. In total, the same internal environment was simulated 240 times. The study focused on the climatic context of the city of Porto Alegre. The focus of the research was the window because this construction element, depending on its size relative to the wall, on its orientation, on its thermal isolation, or on other characteristics, can allow a significant heat exchange between the interior and the exterior of the building, independently of the characteristics of the isolation of the walls. The relationship between the design of the window and the thermal behavior of buildings is discussed based on the RTQ-R, because this is the classification regulation of the level of energy efficiency of residential buildings present in the country. At the end of the work, the influence of the parameters size, orientation and shading for thermal behavior of internal environments is discussed based on the results of the EnergyPlus 7.0 - quantification tool - and RTQ-R - qualification tool. As a result of the simulation made with the EnergyPlus 7.0, information was obtained about how the size, the orientation and the shading of the windows influence the thermal behavior of the internal environment. The analysis made with the RTQ-R equations led to results which are in general compatible with the simulations, despite the lower sensibility of this qualitative tool. In the analysis made with the EnergyPlus 7.0, the size was the variable with the greatest influence. Using the RTQ-R, the variable that was the most influential was the shading. It was also observed that the equations of the RTQ-R are useful for the definition of orientation, size and shading of windows, characteristics which are essential to improve the thermal behavior of internal environments. Therefore, the use of the equations as a tool to support the development of projects is recommended. The EnergyPlus was also showed as a tool able to help select the best design strategies. Thus, the two tools are complementary.
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Desenho de aberturas e comportamento térmico de ambientes de simulação : qualificação e quantificação para região climática de Porto Alegre / Windows Design and Thermal Behavior of Environment: qualification and quantification for climatic region of Porto AlegreZiebell, Clarissa Sartori January 2013 (has links)
O objetivo dessa dissertação foi estudar a relação entre o desenho da abertura e o comportamento térmico de ambientes internos de simulação. Para tanto, o comportamento foi quantificado a partir da energia consumida pelo ar-condicionado para manter o ambiente interno com temperaturas aceitáveis para o conforto térmico. Dessa forma, quanto menor a energia consumida, melhor o comportamento térmico do ambiente. A energia consumida foi obtida através de simulação com o software EnergyPlus 7.0. Os parâmetros investigados foram baseados nas variáveis das equações do RTQ-R (Regulamento Técnico da Qualidade para o Nível de Eficiência Energética das Edificações Residenciais). Para o estudo foram simulados ambientes onde em cada simulação era variada a orientação (norte, nordeste, leste, sudeste, sul, sudoeste, oeste e noroeste) o tamanho (cinco diferentes tamanhos) e a existência ou não de dispositivos de sombreamento das aberturas. Como análise complementar, foi também estudado a influência da intensificação da ventilação durante as noites de verão no comportamento térmico de ambientes. No total, o mesmo ambiente foi simulado 240 vezes. O estudo se concentrou no contexto climático da cidade de Porto Alegre. O foco da pesquisa foi a abertura porque esse elemento de construção, dependendo de seu tamanho em relação à parede, de sua orientação, de sua vedação, ou de outras características, pode permitir uma troca térmica significativa entre o interior e o exterior da edificação, independentemente das características de isolamento das paredes. A relação entre o desenho da abertura e o comportamento térmico de ambientes é discutida tendo como base o RTQ-R, pois esse é o regulamento de classificação do nível de eficiência energética de edificações residenciais vigente no país. Ao final do trabalho, a influência dos parâmetros tamanho, orientação e sombreamento para o comportamento térmico de ambientes é discutida tendo como base os resultados do EnergyPlus 7.0 – ferramenta de quantificação – e do RTQ-R – ferramenta de qualificação. Como resultado das simulações feitas com o EnergyPlus 7.0, obteve-se informação sobre a forma pela qual o tamanho, a orientação e o sombreamento das aberturas influenciam o comportamento térmico de ambientes. As análises feitas com o uso das equações do RTQ-R levaram a resultados de maneira geral compatíveis com as simulações, apesar da menor sensibilidade dessa ferramenta qualitativa. Nas análises com o EnergyPlus 7.0, o tamanho foi a variável que apresentou maior influência. Com o uso do RTQ-R, a variável que se mostrou mais influente foi o sombreamento. Foi observado ainda que as equações do RTQ-R ajudam na definição da orientação, do tamanho e do sombreamento das aberturas, características que são essenciais para aprimorar o comportamento térmico de ambientes. Portanto, o uso das equações como ferramenta de suporte ao desenvolvimento de projetos é recomendável. O EnergyPlus também se mostrou uma ferramenta capaz de auxiliar a escolha das melhores estratégias de projeto. Sendo assim, as duas ferramentas se complementam. / The objective of this dissertation was to demonstrate the relationship between the design of the window and the thermal behavior of simulated internal environments. The thermal behavior was quantified from the energy consumed by the air conditioning system to maintain the internal environment with acceptable temperatures for thermal comfort. Thus, the lower the energy consumed, the better the thermal performance of the internal environment. The amount of energy consumed was obtained by simulation with the software EnergyPlus 7.0. The parameters investigated were based on the variables of the equations of RTQ-R (Quality Technical Regulation for the Level of Energy Efficiency of Residential Buildings). For the study internal environments were simulated, where in each simulation were varied orientation (north, northeast, east, southeast, south, southwest, west and northwest) size (five different sizes) and the presence or absence of shading window devices. As a complement, was also studied the influence of the intensification of ventilation during the summer nights on the thermal behavior of internal environments. In total, the same internal environment was simulated 240 times. The study focused on the climatic context of the city of Porto Alegre. The focus of the research was the window because this construction element, depending on its size relative to the wall, on its orientation, on its thermal isolation, or on other characteristics, can allow a significant heat exchange between the interior and the exterior of the building, independently of the characteristics of the isolation of the walls. The relationship between the design of the window and the thermal behavior of buildings is discussed based on the RTQ-R, because this is the classification regulation of the level of energy efficiency of residential buildings present in the country. At the end of the work, the influence of the parameters size, orientation and shading for thermal behavior of internal environments is discussed based on the results of the EnergyPlus 7.0 - quantification tool - and RTQ-R - qualification tool. As a result of the simulation made with the EnergyPlus 7.0, information was obtained about how the size, the orientation and the shading of the windows influence the thermal behavior of the internal environment. The analysis made with the RTQ-R equations led to results which are in general compatible with the simulations, despite the lower sensibility of this qualitative tool. In the analysis made with the EnergyPlus 7.0, the size was the variable with the greatest influence. Using the RTQ-R, the variable that was the most influential was the shading. It was also observed that the equations of the RTQ-R are useful for the definition of orientation, size and shading of windows, characteristics which are essential to improve the thermal behavior of internal environments. Therefore, the use of the equations as a tool to support the development of projects is recommended. The EnergyPlus was also showed as a tool able to help select the best design strategies. Thus, the two tools are complementary.
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Desenho de aberturas e comportamento térmico de ambientes de simulação : qualificação e quantificação para região climática de Porto Alegre / Windows Design and Thermal Behavior of Environment: qualification and quantification for climatic region of Porto AlegreZiebell, Clarissa Sartori January 2013 (has links)
O objetivo dessa dissertação foi estudar a relação entre o desenho da abertura e o comportamento térmico de ambientes internos de simulação. Para tanto, o comportamento foi quantificado a partir da energia consumida pelo ar-condicionado para manter o ambiente interno com temperaturas aceitáveis para o conforto térmico. Dessa forma, quanto menor a energia consumida, melhor o comportamento térmico do ambiente. A energia consumida foi obtida através de simulação com o software EnergyPlus 7.0. Os parâmetros investigados foram baseados nas variáveis das equações do RTQ-R (Regulamento Técnico da Qualidade para o Nível de Eficiência Energética das Edificações Residenciais). Para o estudo foram simulados ambientes onde em cada simulação era variada a orientação (norte, nordeste, leste, sudeste, sul, sudoeste, oeste e noroeste) o tamanho (cinco diferentes tamanhos) e a existência ou não de dispositivos de sombreamento das aberturas. Como análise complementar, foi também estudado a influência da intensificação da ventilação durante as noites de verão no comportamento térmico de ambientes. No total, o mesmo ambiente foi simulado 240 vezes. O estudo se concentrou no contexto climático da cidade de Porto Alegre. O foco da pesquisa foi a abertura porque esse elemento de construção, dependendo de seu tamanho em relação à parede, de sua orientação, de sua vedação, ou de outras características, pode permitir uma troca térmica significativa entre o interior e o exterior da edificação, independentemente das características de isolamento das paredes. A relação entre o desenho da abertura e o comportamento térmico de ambientes é discutida tendo como base o RTQ-R, pois esse é o regulamento de classificação do nível de eficiência energética de edificações residenciais vigente no país. Ao final do trabalho, a influência dos parâmetros tamanho, orientação e sombreamento para o comportamento térmico de ambientes é discutida tendo como base os resultados do EnergyPlus 7.0 – ferramenta de quantificação – e do RTQ-R – ferramenta de qualificação. Como resultado das simulações feitas com o EnergyPlus 7.0, obteve-se informação sobre a forma pela qual o tamanho, a orientação e o sombreamento das aberturas influenciam o comportamento térmico de ambientes. As análises feitas com o uso das equações do RTQ-R levaram a resultados de maneira geral compatíveis com as simulações, apesar da menor sensibilidade dessa ferramenta qualitativa. Nas análises com o EnergyPlus 7.0, o tamanho foi a variável que apresentou maior influência. Com o uso do RTQ-R, a variável que se mostrou mais influente foi o sombreamento. Foi observado ainda que as equações do RTQ-R ajudam na definição da orientação, do tamanho e do sombreamento das aberturas, características que são essenciais para aprimorar o comportamento térmico de ambientes. Portanto, o uso das equações como ferramenta de suporte ao desenvolvimento de projetos é recomendável. O EnergyPlus também se mostrou uma ferramenta capaz de auxiliar a escolha das melhores estratégias de projeto. Sendo assim, as duas ferramentas se complementam. / The objective of this dissertation was to demonstrate the relationship between the design of the window and the thermal behavior of simulated internal environments. The thermal behavior was quantified from the energy consumed by the air conditioning system to maintain the internal environment with acceptable temperatures for thermal comfort. Thus, the lower the energy consumed, the better the thermal performance of the internal environment. The amount of energy consumed was obtained by simulation with the software EnergyPlus 7.0. The parameters investigated were based on the variables of the equations of RTQ-R (Quality Technical Regulation for the Level of Energy Efficiency of Residential Buildings). For the study internal environments were simulated, where in each simulation were varied orientation (north, northeast, east, southeast, south, southwest, west and northwest) size (five different sizes) and the presence or absence of shading window devices. As a complement, was also studied the influence of the intensification of ventilation during the summer nights on the thermal behavior of internal environments. In total, the same internal environment was simulated 240 times. The study focused on the climatic context of the city of Porto Alegre. The focus of the research was the window because this construction element, depending on its size relative to the wall, on its orientation, on its thermal isolation, or on other characteristics, can allow a significant heat exchange between the interior and the exterior of the building, independently of the characteristics of the isolation of the walls. The relationship between the design of the window and the thermal behavior of buildings is discussed based on the RTQ-R, because this is the classification regulation of the level of energy efficiency of residential buildings present in the country. At the end of the work, the influence of the parameters size, orientation and shading for thermal behavior of internal environments is discussed based on the results of the EnergyPlus 7.0 - quantification tool - and RTQ-R - qualification tool. As a result of the simulation made with the EnergyPlus 7.0, information was obtained about how the size, the orientation and the shading of the windows influence the thermal behavior of the internal environment. The analysis made with the RTQ-R equations led to results which are in general compatible with the simulations, despite the lower sensibility of this qualitative tool. In the analysis made with the EnergyPlus 7.0, the size was the variable with the greatest influence. Using the RTQ-R, the variable that was the most influential was the shading. It was also observed that the equations of the RTQ-R are useful for the definition of orientation, size and shading of windows, characteristics which are essential to improve the thermal behavior of internal environments. Therefore, the use of the equations as a tool to support the development of projects is recommended. The EnergyPlus was also showed as a tool able to help select the best design strategies. Thus, the two tools are complementary.
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Optimering av klassrumsmiljön i en ny skolbyggnad i Västerås : En studie om fönsterplacering och energiförlusterFadi, Kunda, Nahla, Alhamada, Mert, Celen January 2023 (has links)
Purpose: The purpose of this study was to plan blueprints for a school located Härbregatan and Vallby Skolgata in Västerås with a focus on energy losses and window placement to choose the most suitable types of windows to obtain a good internal environment. Method: The methodology used to conduct this thesis was based on earlier case studies, literature book and literature reviews in the form of legal specification from Boverket Byggregel (BBR) that had a significant impact on how the school was designed, interior and exterior views. Results: The study demonstrated how important window types and selection was for the students and the teachers occupying the classrooms because windows are a vital source of light, energy and encouragement due to the daylight. Larger windows minimize the need for electrical lighting but increases the risk of energy loss due to inadequate insulation resulting in an impact on the indoor environment and causing a higher energy usage. The size of the window also has an impact on specific transmission losses, thermal bridges, heat losses and as well as the solar radiation passing through the glass, according to this study. Conclusions: The study came to the conclusion that while windows have a significant role in these aspects, additional aspects that include the size of walls, doors, floors and ceiling also play an essential part. Larger windows lead to increased transmission losses and thermal bridges, but at the same time it lets in more daylight and sunlight in the form of heat energy, therefore larger windows are a better choice to use in the school building.
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Optimering av dubbelspaltigt värmefönster / Optimization of double slotted heat exchange windowGil Castro, Roberson Manuel André, Henriksson, Claes Evald January 2020 (has links)
Utvecklad för att bibehålla termisk komfort och minska exergianvändningen, Free Heat Exchange Window [FHEW] är en fönsterdesign som är tänkt att ersätta konventionella värmesystem i bostäder och kontorsbyggnader. Baserat på dubbelspaltkonceptet kommer fönstret utgöra en värmekälla under kalla vinterdagar och en värmesänka under varmare sommardagar. För att värdera huruvida teknologin kan bibehålla tillräcklig termisk komfort och avgöra dess optimala parameterkonfiguration utifrån byggnadens effektbehov skapas två olika modeller. En grundar sig på en datorsimulering av en lägenhet i COMSOL Multiphysics och den andra är en analytisk metod för beräkning av energibalanser i MATLAB. Resultaten från båda modellerna påvisade att hög inströmningstemperatur och låg inströmningshastighet är att föredra för minimering av effektbehovet. Å andra sidan ger en låg inströmnings temperatur och hög strömningshastighet en upphov till högre termisk komfort. Valet av den isolerande gasen som används i mittersta gas-spalten bedöms ha låg inverkan på prestandan, särskilt för höga strömningshastigheter. En alternativ modell med den isolerande gas-spalten omplacerad närmast utomhuset skulle kunna framföra bättre användning av den isolerande gas-spaltens funktion. Datorsimuleringen jämförs avslutningsvis med en ekvivalent lägenhetsmodell med enkelspaltiga fönster och element som värmekälla. Denna modell kräver lägre effekt, men är samtidigt mindre flexibel och inducerar en lägre termisk komfort. Datorsimuleringen rekommenderas på grund av dess antaganden och i vissa fall orimliga resultat endast som jämförelse med andra liknande modellen, snarare än verkliga data. / Developed to maintain thermal comfort and reduce exergy usage, Free Heat Exchange Window [FHEW] is a modern window design aimed to replace current heat systems in homes and office buildings. Based on the double slot concept, the window can be used as a heat source during cold winter days and heat sink during warmer summer days. To evaluate if the technology is viable to maintain thermal comfort and determine its optimal parameters with respect to energy efficiency, two different models will be made. One is based on computer simulations in COMSOL Multiphysics and one is based on analytical equations in MATLAB. The results from both models proved that a higher inflow temperature and a lower flow rate was prefered to minimize power demand. On the contrary, a lower inflow temperature and a higher flow rate is preferred to achieve the best thermal comfort. The differences between the choice of insulation gas gave unnoticeable deviation for indoor heat exchange for high flow rates. An alternative window model could reposition the insulation gas-gap to be between the whole system and the outdoors environment, instead of having it installed between the flowing air-gaps, for better use of the low thermal conductivity. The computer simulation is finally compared with an equivalent model using regular single slot windows and radiators as heaters. This model requires less energy but is less flexible and induces a less desirable thermal comfort. The computer simulation is due to its assumptions and in some instances implausible results only recommended to be compared to similar models, rather than real data.
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