Study of natural ventilation for a modular façade system in wind tunnel tests

Wind tunnel tests are a reliable tool to determine the effect of natural ventilation on buildings. This paper presents results of wind tunnel tests conducted to evaluate the influence of ventilation modules positioning on a façade system. Modules positioning was modified, resulting in different façade configurations. The tests were carried out with the use of a model, varying the position of the ventilation modules in the façade configuration. The cases tested were six ventilation modules positioned below the window-sill (ventilated window-sill), and three ventilation modules positioned above and below the façade. The façade system proposed was movable and interchangeable so that the same basic model could be used to test the possibilities for ventilation. Wind speed measurements were taken inside and outside the model for the different façades configurations to evaluate the best performance in relation to natural ventilation. Singleâ sided and Cross ventilation were considered for wind speed measurements. Results show the use of six ventilation modules positioned below the window-sill, forming "a ventilated window-sill" is the best solution in terms of natural ventilation

Glazing façade modules : daylighting performance simulation for Bragança, Coimbra, Évora and Faro

The daylighting performance improvement is one better strategy to reduce the artificial lighting consumption in buildings and obviously requires solar radiation from the exterior. Daylighting comes not only from direct sunlight but also from illumination provided by the sky on overcast days. Particular attention must be given to daylighting while designing a building when the aim is to maximize visual comfort or to reduce energy consumption. Visual comfort of glazing façades is a fundamental characteristic to the global comfort. Additionally, this work reports a part of the results of an ongoing investigation about a new façade system concept: "Façade Modules for Eco-Efficient Refurbishment of Buildings", especially on the daylighting performance of double glazing modules. Ecotect 5.6 software was used to obtain the daylight factor and illuminance level for four Portugal cities and two double glazing façade modules, composed by green solar control glass and low-e glass; selfcleaning glass and float clear glass. A typical dwelling room (25m²) was simulated. Daylight factor and illuminance level were obtained by means of computational simulations. These results were compared to daylighting standards and recommendations. Results showed a better daylight performance for double self-cleaning glazing for all cities. A lower performance was observed when using green solar control glass and low-e glass.Erasmus Mundus - ISAC – Improving Skills Across Continent

Passive façade solutions: tromble wall thermal performance and glazing daylighting performance for Guimarães - Portugal

Recently façade systems have integrated passive solutions to reduce the energy consumption in buildings and improve their occupants’ comfort. This paper reports the results of the thermal performance of Trombe walls and daylighting of glazing modules of a façade system in Portugal. Trombe walls are massive walls separated from the outdoors by glazing and an air space, which absorbs the solar energy and releases it selectively to the inside of the building at night. Computational simulations were carried out with the Design Builder, Ecotect and Desktop Radiance programs. The use of Trombe walls and double self-cleaning glass in the façade system led to a decrease in the heating energy needs.(undefined)The authors gratefully acknowledge the financial support provided by Erasmus Mundus ISAC - Improving Skills Across Continents for this researc

Different module placements in a modular façade system for natural ventilation

Nowadays natural ventilation has gained prominence because its correct use can reduce energy consumption for cooling systems and improve thermal comfort among users. In this paper, we report on the modelling initiative, based on the wind tunnel tests that were carried out for the determination of the influence of natural ventilation in buildings. Indeed, the renewal of air in a closed environment without using an air conditioning system with mechanical elements can lead to energy savings and, in addition, provide air quality.The wind tunnel tests were carried out by varying the positioning of six ventilation modules in the façade system configuration. The modules were positioned below the window-sill (ventilated window-sill) as well as separately above and below the façade. The wind speed measurements were taken inside and outside the model for the different façades configurations to evaluate the best performance in relation to natural ventilation. The results supported the positioning of the six ventilation modules below the window-sill, forming a â ventilated window-sillâ as the most effective natural ventilation solution.The authors gratefully acknowledge the financial support provided by Erasmus Mundus ISAC – Improving Skills Across Continents for this study

Estudo da eficiência energética de fachadas fotovoltaicas em Portugal

A redução dos níveis de CO2 emitidos para a atmosfera, resultantes do consumo energético, vem constituindo ao longo dos últimos anos uma preocupação global. Neste sentido, a União Européia vem desenvolvendo um conjunto de documentos que visam a regulamentação da redução do consumo de energia e das emissões de gases com efeito estufa, e aumento da quota de energias renováveis até 2020. O uso de sistemas fotovoltaicos em fachadas se insere nesse contexto de aumento da quota de energias renováveis. Os ganhos que a fachada fotovoltaica apresenta são referentes à eficiência energética e ao desempenho ambiental dos edifícios. Diante desses aspectos foi executado um estudo para Portugal (Porto, Lisboa e Faro) sobre uso de painéis fotovoltaicos em fachadas por meio de simulação computacional no qual foram analisadas as características dos painéis mais eficientes. Para alcançar tais resultados, a metodologia incluiu simulações computacionais realizadas com o software SolTerm 5.0. Com base nos resultados, observou-se que existe um potencial para o uso de painéis fotovoltaicos em Portugal, principalmente para latitudes próximas à Faro. Além disso, observou-se que o tipo de tecnologia com maior rendimento são os painéis de silício policristalino na posição inclinada, sendo que o tipo de painel fotovoltaico mais eficiente foi o Kyocera KC167G-2, seguido do painel BP 3160. Através da comparação dos resultados de simulação computacional com outros estudos, verificou-se que a ferramenta computacional utilizada se apresenta viável para a análise da eficiência energética deste tipo de sistema. The reduction in CO2 emitted in the atmosphere resulting from energy consumption has constituted a global concern over the past years. Thus, the EU has developed a set of proposals in order to reduce the energy consumption and emissions of greenhouse gases, encouraging the use of renewable energy until 2020. On this topic, the photovoltaic facade is known to be a solution that allows both energy efficiency and environmental performance of buildings. In this respect, a study of facade systems that incorporate photovoltaic panels, considering computational simulations for Portugal, is presented in this work. The main objective of the present research is to analyze the characteristics and parameters that define of more efficient systems based on computer simulations. On this purpose, the version 5.0 of SolTerm computer program was used. The results show that there is a high potential on the use of the proposed technology in Portugal, especially in Faro region, because of its latitude. Besides, inclined polycrystalline silicon solar panels achieved the best results. Considering the energy efficiency and environmental performance, the most efficient panel was the Kyocera KC167G-2, followed by BP 3160. It should be noted that the comparison of results obtained by numerical simulation and the ones presented in literature show that the use of computer programs is viable to the analysis of energy efficiency of the photovoltaic systems in façades.Os autores agradecem ao Programa Erasmus Mundus ISAC - Improving Skills Across Continents pelo apoio financeiro a esta pesquisa.info:eu-repo/semantics/publishedVersio

Study of natural ventilation in wind tunnels and influence of the position of ventilation modules and types of grids on a modular façade system

Natural ventilation requires no energy consumption, which can constitute 25% of a mechanically ventilated building, and both shape and position of inlets and outlets ventilation openings must be properly designed for better natural ventilation performance. Wind tunnel tests are a reliable tool for the determination of the effect of natural ventilation on buildings. This paper reports on results of wind tunnel tests conducted for the evaluation of the influence of the positioning and type of grid of ventilation modules on a façade system. Three ventilation modules were positioned below the window-sill (ventilated window-sill) and three were positioned above and below the façade. Ventilation modules with grid elements positioned vertically and horizontally were tested. Wind speed measurements that considered single-sided and cross ventilation were taken inside and outside the model for the different façade configurations for the evaluation of the best performance in relation to natural ventilation. The façade system proposed is movable and interchangeable, so that the same basic model can be used for the testing of possibilities for ventilation. The results show the use of six ventilation modules positioned below the window-sill and that form a "ventilated window-sill" with a horizontal grid is the best solution regarding natural ventilation. Such a configuration has proved the grid elements of ventilation modules exert a higher influence on the results than the positioning of modules on the façade. Therefore, better conditions of natural ventilation were obtained with a thin and horizontal positioning of the elements.The authors gratefully acknowledge the financial support provided by Erasmus Mundus ISAC – Improving Skills Across Continents.info:eu-repo/semantics/publishedVersio

Eficiência energética de fachadas fotovoltaicas destinadas às diferentes latitudes de Portugal

A redução dos níveis de CO2 emitidos para a atmosfera, resultantes do consumo energético, vem constituindo ao longo dos últimos anos uma preocupação global. Neste sentido, a União Européia vem desenvolvendo um conjunto de documentos que visam a regulamentação da redução do consumo de energia e das emissões de gases com efeito estufa, e aumento da quota de energias renováveis até 2020. O uso de sistemas fotovoltaicos em fachadas se insere nesse contexto de aumento da quota de energias renováveis. Os ganhos que a fachada fotovoltaica apresenta são referentes à eficiência energética e ao desempenho ambiental dos edifícios. Diante desses aspectos foi executado um estudo para Portugal sobre uso de painéis fotovoltaicos em fachadas por meio de simulação computacional no qual foram analisadas as características dos painéis mais eficientes. Para alcançar tais resultados, a metodologia incluiu simulações computacionais realizadas com o software SolTerm 5.0. Com base nos resultados, observou-se que existe um potencial para o uso de painéis fotovoltaicos em Portugal, principalmente para latitudes próximas à Évora. Além disso, observou-se que o tipo de tecnologia com maior rendimento são os painéis de silício policristalino na posição inclinada, sendo que o tipo de painel fotovoltaico mais eficiente foi o Kyocera KC167G-2, seguido do painel BP 3160. Através da comparação dos resultados de simulação computacional com outros estudos, verificou-se que a ferramenta computacional utilizada se apresenta viável para a análise da eficiência energética deste tipo de sistema.The reduction in CO2 emitted in the atmosphere resulting from energy consumption has constituted a global concern over the past years. Thus, the EU has developed a set of proposals in order to reduce the energy consumption and emissions of greenhouse gases, encouraging the use of renewable energy until 2020. On this topic, the photovoltaic facade is known to be a solution that allows both energy efficiency and environmental performance of buildings. In this respect, a study of facade systems that incorporate photovoltaic panels, considering computational simulations for Portugal, is presented in this work. The main objective of the present research is to analyze the characteristics and parameters that define of more efficient systems based on computer simulations. On this purpose, the version 5.0 of SolTerm computer program was used. The results show that there is a high potential on the use of the proposed technology in Portugal, especially in Évora region, because of its latitude. Besides, inclined polycrystalline silicon solar panels achieved the best results. Considering the energy efficiency and environmental performance, the most efficient panel was the Kyocera KC167G-2, followed by BP 3160. It should be noted that the comparison of results obtained by numerical simulation and the ones presented in literature show that the use of computer programs is viable to the analysis of energy efficiency of the photovoltaic systems in façades

Specification of glazings for façades based on spectrophotometric characterization of transmittance

The correct specification of glazings for façades can reduce the energy consumption in buildings. The heat exchange occurs through transparent surfaces and radiation reaches the building as light and heat. Therefore, glazings significantly contribute to the heat transfer between outdoor and indoor spaces and act directly on daylighting and thermal comfort. This paper reports on the spectrophotometric characterization of glazings transmittance for the study of components of a modular façade system and its suitability for the climate of Portugal (temperate climate). The study focused on results of spectrophotometric measurements of optical properties, specifically the transmittance of some types of glazings (solar control, self-cleaning, low-e, float, and extra-clear) and two types of double glazings. The results show the percentage of transmission to ultraviolet, visible, and near-infrared regions and its importance, which enabled the analysis of the glazing efficiency regarding daylighting and the correlation to thermal performance. Subsidies and indications for the specification and adequate uses of transparent surfaces have been presented and complemented the datasheets available from the manufactures.This research was funded by Erasmus Mundus External Cooperation Window–ISAC: Improving Skills Across Continents (Framework Partnership Agreement 2008-1021/001 FRAMEECW L16 Coimbra, Specific Grant Agreement 2008-3628/001-001-MUN-ECW)

Estudo da ventilação natural em túnel de vento para um sistema de fachadas modular

Os ensaios em túnel de vento são uma ferramenta confiável para determinar o efeito da ventilação natural em edifícios. Por meio do presente estudo são analisadas as condições de ventilação de um modelo, de acordo com o posicionamento de módulos de ventilação num sistema de fachadas. Os ensaios foram realizados em túnel de vento, variando a posição dos módulos de ventilação na configuração fachada. Os casos apresentados serão dois, um deles com seis módulos de ventilação posicionados no peitoril da janela (peitoril ventilado) e outro com três módulos de ventilação posicionados acima e abaixo na fachada. Trata-se de um sistema de fachadas móvel e intercambiável, de forma que o mesmo modelo básico fosse utilizado para testar as diferentes possibilidades de ventilação. Medições da velocidade do ar foram obtidas para o interior e exterior do modelo para as diferentes configurações de fachadas, de modo a avaliar o melhor desempenho em relação à ventilação natural. Casos com e sem ventilação cruzada foram considerados para medição da velocidade do ar. Os resultados indicaram que o uso de módulos de ventilação posicionados abaixo do peitoril da janela, formando um peitoril ventilado foi a melhor solução em termos de ventilação natural. Wind tunnel tests are a reliable tool to determine the effect of natural ventilation on buildings. This paper discusses the ventilation conditions of a model, according to the ventilation modules positioning in a façade system. The tests were carried out in a wind tunnel, varying the position of the ventilation modules in the façade configuration. The cases presented were two, one with six ventilation modules positioned below the window-sill (ventilated window-sill), and another with three ventilation modules positioned above and below the façade. The façade system proposed was movable and interchangeable so that the same basic model could be used to test the possibilities for ventilation. Air speed measurements were taken inside and outside the model for the different façades configurations to evaluate the best performance in relation to natural ventilation. Single-sided and Cross ventilation were considered for air speed measurements. Results show the use of six ventilation modules positioned below the window-sill, forming a “ventilated window-sill” was the best solution in terms of natural ventilation.Os autores agradecem o apoio financeiro concedido pelo programa Erasmus Mundus ISAC – Improving Skills Across Continents a presente pesquisa.info:eu-repo/semantics/publishedVersio