ABSTRACT Numerous demonstration studies have identified a large potential for adaptive facades to... more ABSTRACT Numerous demonstration studies have identified a large potential for adaptive facades to improve the energy performance and indoor environmental quality of buildings. However, to enable widespread application of these concepts, there is a need for more research and development, leading to innovative materials and components, and better scalable solutions. One of the barriers that hinders innovation and adoption of new technologies for improved energy efficiency in buildings is known as the Valley of Death – the metaphor which describes the lack of resources and expertise that impedes new ideas in their transition from lab to market. In this paper, the use of building performance simulation is put forward as a useful tool in the product development process of innovative adaptable building envelope components. By discussing the background principles and details of two application examples, we show how building performance simulation can become a useful tool to help close the gap between building material innovation and successful building application.
The irregular reflection and transmission properties of innovative fenestration components allow ... more The irregular reflection and transmission properties of innovative fenestration components allow to redirect, and to selectively admit or block solar irradiation based on its incident direction. Compared to e.g. systems that implement adaptivity to external conditions by mechanical transformations, such tailored light scattering properties promise to reduce the complexity of installation, operation and maintenance as well as the impact on outward view and the aesthetical appearance of buildings. Examples of such innovative fenestration techniques, e.g. light redirecting films and Venetian blinds featuring irregular reflection properties, are presented with their gonio-photometrically measured light scattering properties. Techniques to model such innovative, optically complex fenestration in building simulation software to support product development and planning are presented. The effects on daylight availability, glare and solar gains are demonstrated for exemplary cases. Prelimina...
IEEE Transactions on Evolutionary Computation, 2002
Keywords: 454/ICOM Reference ICOM-ARTICLE-2002-002 Record created on 2008-01-24, modified on 2016... more Keywords: 454/ICOM Reference ICOM-ARTICLE-2002-002 Record created on 2008-01-24, modified on 2016-08-08
The potential of exemplary organic and inorganic Phase Change Materials (PCMs) as façade integrat... more The potential of exemplary organic and inorganic Phase Change Materials (PCMs) as façade integrated storage is tested. The impact of two PCMs on heat flows is assessed in comparison with water and concrete. The simulation-study employs a transient Modelica simulation model of a test cell featuring the Solar Energy Balanced Façade (SEBF). It is shown that, when compared to water, PCMs of identical volume change the seasonal energy balance in winter and summer by only ± 4%. Other than water, the PCMs maintain this effect even if the storage volume decreases. Due to spatial constraints, this can support the integration of thermal storage in façade design considerably. Preliminary results indicate that designing thermal storage in façades with PCMs must not only consider the latent heat storage capacity, but also take into account the combined effects of latent heat capacity, melting point, conductivity, and dead load. The application of PCMs promises to foster the integration of the te...
ZusammenfassungDer Rückgang der Heiratsziffern sowie die Verschiebung der Eheschließung auf einen... more ZusammenfassungDer Rückgang der Heiratsziffern sowie die Verschiebung der Eheschließung auf einen späteren Zeitpunkt im Lebensverlauf können u.a. durch neue Formen des Zusammenlebens erklärt werden. Eine in diesem Zusammenhang für Deutschland noch weitgehend ungeklärte Frage ist, ob durch eine „Probeehe“ das Scheidungsrisiko einer nachfolgenden Ehe verringert werden kann, weil - wie die „weeding“-Hypothese postuliert - instabile Partnerschaften vor einer Eheschließung beendet werden können. Zahlreiche Befunde aus verschiedenen Ländern können diese Annahme nicht bestätigen: Sie zeigen vielmehr, daß voreheliches Zusammenleben mit einem höheren Scheidungsrisiko verbunden ist. Der Aufsatz überprüft für Deutschland die „weeding“-Hypothese anhand eines aktuellen und eigens für das Thema „Ehescheidung“ konzipierten Datensatzes. Die Analyse zeigt erstens, daß Paare, die vor der Ehe zusammengelebt haben, aufgrund ihrer Merkmale einem höheren Scheidungsrisiko unterliegen und daher ein inhären...
ABSTRACT Stability of load carrying elements in glass The increasing demand in modern architectur... more ABSTRACT Stability of load carrying elements in glass The increasing demand in modern architecture for more slender and lighter structures requires the use of new construction materials. Glass, a material that has been used for a long time in windows as a filling material, has much to offer in this regard due to its very high compressive strength and transparency. For this reason, there is a growing trend to extend the use of glass sheets to load carrying elements such as columns, beams and panels. Due to their high slenderness and high compressive strength, such elements tend to fail because of instability (i.e. column buckling, lateral torsional buckling or plate buckling). At the moment little knowledge exists about the load carrying behaviour of glass structural elements, and existing design methods for other materials (i.e. steel) have been found to be unsuitable for direct transfer to the design of glass panels. With this in mind, the main objectives of the current thesis are: The study of the load carrying behaviour of glass elements which may fail due to lack of stability by means of laboratory tests and analytical and numerical models, as well as the study of the main influencing parameters. Discussion of possible design methods for glass elements which may fail due to lack of stability for the three main stability problems (column buckling, lateral torsional buckling and plate buckling) and proposition of possible aids for design such as buckling curves. The main influencing parameters (dispersion of the glass thickness, initial deformation) on the load carrying behaviour of glass elements which may fail due to lack of stability have been measured and are evaluated herein using statistical methods. The breakage stress, the thermal prestress and the effective tensile strength are defined and explained. Existing models to determine the tensile strength of glass are discussed. The column buckling behaviour of single layer and laminated safety glass is studied by means of column buckling tests, which are compared to analytical and numerical models. The models are used to study the influence of the main parameters, particularly the shear connection due to the interlayer (PVB) in laminated safety glass, on the load carrying behaviour and buckling strength of glass elements. On the basis of this study different possible design methods for column buckling of glass elements in compression are proposed and discussed. It is shown that a second order stress analysis is the most appropriate method for glass. As a further simplification, the cross section of a laminated safety glass structural element can be modelled as a monolithic cross section with an effective thickness. Analytical and numerical models for the lateral torsional buckling of glass beams are also verified by a comparison to test results. Along with a study of the main parameters, different methods to determine the lateral torsional buckling strength are discussed, and it is shown that buckling curves for lateral torsional buckling should be developed for glass beams using a slenderness ratio based on effective tensile strength. As a result of numerical simulations, recommendations for the future development of lateral torsional buckling curves of glass beams are given. The column buckling behaviour of single layer and laminated safety glass is also studied by means of column buckling tests, analytical and numerical models. It is shown that glass panels have a large post critical load carrying capacity but the way the loads are introduced into the panels, as well as the buckling shape, have an important influence on the plate buckling capacity. A design method with buckling curves using a slenderness ratio based on effective tensile strength seems applicable for the design of glass panels. As a result of numerical simulations, recommendations for the future development of plate buckling curves for plate glass elements under compression are given. Stabilité des éléments porteurs en verre La tendance actuelle en architecture moderne pour des structures toujours plus élancées et légères requiert l'utilisation de nouveaux matériaux de construction. Le verre, un matériau longtemps utilisé comme élément de remplissage des fenêtres, a beaucoup plus à offrir eu égard à sa très haute résistance à la compression et à sa transparence. C'est pourquoi on cherche à étendre l'utilisation des feuilles de verre pour en faire des éléments porteurs tels que poteaux, poutres ou parois. Ces éléments étant très élancés, ils ont tendance à se ruiner par instabilité lorsqu'ils sont soumis à la compression (ruine par flambage, déversement ou voilement). Actuellement, il existe très peu de connaissances dans le domaine de la capacité portante des éléments structuraux en verre, et les méthodes de dimensionnement développées pour d'autres matériaux de construction (par exemple l'acier) se sont avérées difficiles à appliquer directement au…
... The main objective of research work being conducted is to develop a design method for stabili... more ... The main objective of research work being conducted is to develop a design method for stability-critical load carry-ing glass elements which may fail due to lack of stability, ie columnbuckling, plate buckling and lateral torsional buckling [2]. In this paper the most im-portant ...
ABSTRACT Due to the large increase of structural glass applications, the lateral torsional buckli... more ABSTRACT Due to the large increase of structural glass applications, the lateral torsional buckling behavior of glass beams actually represents a topic of great interest for researchers. Although several analytical models and design approaches exist in literature, various aspects complicate the realistic prediction of their typical out-of-plane response, especially if composed of two (or more) laminated glass sheets. Based on viscoelastic numerical results and predictions of a large experimental campaign of lateral torsional buckling tests performed on PVB and SG beams, the paper investigates the accuracy of existing analytical models in the prediction of the elastic critical load and load-lateral displacement path of these elements.
Modern cities face a climatic problem due to the high proportion of sealed surfaces that increase... more Modern cities face a climatic problem due to the high proportion of sealed surfaces that increase the urban heat island (UHI) effect. Green surfaces offer a way to mitigate the UHI effect, as they positively influence the thermal energy storage and air temperature. To support an increase of green surfaces in the limited resources of cities, vertical spaces, e.g. façades, must be exploited. A possible realisation of a vertical green system are overgrown rope façades. Overgrown rope façades have pre-fitted ropes in front of façades on which climbing plants can grow. However, such systems have to deal with dynamic wind forces, which pose static challenges to the climbing system. In order to design such systems for the effective wind forces, so-called drag coefficients of the climbing plants must be known. Unfortunately, there are no guidelines or known values that provide such specific drag coefficients for climbing plants. In this study, based on a study review of relevant data for dr...
ABSTRACT Numerous demonstration studies have identified a large potential for adaptive facades to... more ABSTRACT Numerous demonstration studies have identified a large potential for adaptive facades to improve the energy performance and indoor environmental quality of buildings. However, to enable widespread application of these concepts, there is a need for more research and development, leading to innovative materials and components, and better scalable solutions. One of the barriers that hinders innovation and adoption of new technologies for improved energy efficiency in buildings is known as the Valley of Death – the metaphor which describes the lack of resources and expertise that impedes new ideas in their transition from lab to market. In this paper, the use of building performance simulation is put forward as a useful tool in the product development process of innovative adaptable building envelope components. By discussing the background principles and details of two application examples, we show how building performance simulation can become a useful tool to help close the gap between building material innovation and successful building application.
The irregular reflection and transmission properties of innovative fenestration components allow ... more The irregular reflection and transmission properties of innovative fenestration components allow to redirect, and to selectively admit or block solar irradiation based on its incident direction. Compared to e.g. systems that implement adaptivity to external conditions by mechanical transformations, such tailored light scattering properties promise to reduce the complexity of installation, operation and maintenance as well as the impact on outward view and the aesthetical appearance of buildings. Examples of such innovative fenestration techniques, e.g. light redirecting films and Venetian blinds featuring irregular reflection properties, are presented with their gonio-photometrically measured light scattering properties. Techniques to model such innovative, optically complex fenestration in building simulation software to support product development and planning are presented. The effects on daylight availability, glare and solar gains are demonstrated for exemplary cases. Prelimina...
IEEE Transactions on Evolutionary Computation, 2002
Keywords: 454/ICOM Reference ICOM-ARTICLE-2002-002 Record created on 2008-01-24, modified on 2016... more Keywords: 454/ICOM Reference ICOM-ARTICLE-2002-002 Record created on 2008-01-24, modified on 2016-08-08
The potential of exemplary organic and inorganic Phase Change Materials (PCMs) as façade integrat... more The potential of exemplary organic and inorganic Phase Change Materials (PCMs) as façade integrated storage is tested. The impact of two PCMs on heat flows is assessed in comparison with water and concrete. The simulation-study employs a transient Modelica simulation model of a test cell featuring the Solar Energy Balanced Façade (SEBF). It is shown that, when compared to water, PCMs of identical volume change the seasonal energy balance in winter and summer by only ± 4%. Other than water, the PCMs maintain this effect even if the storage volume decreases. Due to spatial constraints, this can support the integration of thermal storage in façade design considerably. Preliminary results indicate that designing thermal storage in façades with PCMs must not only consider the latent heat storage capacity, but also take into account the combined effects of latent heat capacity, melting point, conductivity, and dead load. The application of PCMs promises to foster the integration of the te...
ZusammenfassungDer Rückgang der Heiratsziffern sowie die Verschiebung der Eheschließung auf einen... more ZusammenfassungDer Rückgang der Heiratsziffern sowie die Verschiebung der Eheschließung auf einen späteren Zeitpunkt im Lebensverlauf können u.a. durch neue Formen des Zusammenlebens erklärt werden. Eine in diesem Zusammenhang für Deutschland noch weitgehend ungeklärte Frage ist, ob durch eine „Probeehe“ das Scheidungsrisiko einer nachfolgenden Ehe verringert werden kann, weil - wie die „weeding“-Hypothese postuliert - instabile Partnerschaften vor einer Eheschließung beendet werden können. Zahlreiche Befunde aus verschiedenen Ländern können diese Annahme nicht bestätigen: Sie zeigen vielmehr, daß voreheliches Zusammenleben mit einem höheren Scheidungsrisiko verbunden ist. Der Aufsatz überprüft für Deutschland die „weeding“-Hypothese anhand eines aktuellen und eigens für das Thema „Ehescheidung“ konzipierten Datensatzes. Die Analyse zeigt erstens, daß Paare, die vor der Ehe zusammengelebt haben, aufgrund ihrer Merkmale einem höheren Scheidungsrisiko unterliegen und daher ein inhären...
ABSTRACT Stability of load carrying elements in glass The increasing demand in modern architectur... more ABSTRACT Stability of load carrying elements in glass The increasing demand in modern architecture for more slender and lighter structures requires the use of new construction materials. Glass, a material that has been used for a long time in windows as a filling material, has much to offer in this regard due to its very high compressive strength and transparency. For this reason, there is a growing trend to extend the use of glass sheets to load carrying elements such as columns, beams and panels. Due to their high slenderness and high compressive strength, such elements tend to fail because of instability (i.e. column buckling, lateral torsional buckling or plate buckling). At the moment little knowledge exists about the load carrying behaviour of glass structural elements, and existing design methods for other materials (i.e. steel) have been found to be unsuitable for direct transfer to the design of glass panels. With this in mind, the main objectives of the current thesis are: The study of the load carrying behaviour of glass elements which may fail due to lack of stability by means of laboratory tests and analytical and numerical models, as well as the study of the main influencing parameters. Discussion of possible design methods for glass elements which may fail due to lack of stability for the three main stability problems (column buckling, lateral torsional buckling and plate buckling) and proposition of possible aids for design such as buckling curves. The main influencing parameters (dispersion of the glass thickness, initial deformation) on the load carrying behaviour of glass elements which may fail due to lack of stability have been measured and are evaluated herein using statistical methods. The breakage stress, the thermal prestress and the effective tensile strength are defined and explained. Existing models to determine the tensile strength of glass are discussed. The column buckling behaviour of single layer and laminated safety glass is studied by means of column buckling tests, which are compared to analytical and numerical models. The models are used to study the influence of the main parameters, particularly the shear connection due to the interlayer (PVB) in laminated safety glass, on the load carrying behaviour and buckling strength of glass elements. On the basis of this study different possible design methods for column buckling of glass elements in compression are proposed and discussed. It is shown that a second order stress analysis is the most appropriate method for glass. As a further simplification, the cross section of a laminated safety glass structural element can be modelled as a monolithic cross section with an effective thickness. Analytical and numerical models for the lateral torsional buckling of glass beams are also verified by a comparison to test results. Along with a study of the main parameters, different methods to determine the lateral torsional buckling strength are discussed, and it is shown that buckling curves for lateral torsional buckling should be developed for glass beams using a slenderness ratio based on effective tensile strength. As a result of numerical simulations, recommendations for the future development of lateral torsional buckling curves of glass beams are given. The column buckling behaviour of single layer and laminated safety glass is also studied by means of column buckling tests, analytical and numerical models. It is shown that glass panels have a large post critical load carrying capacity but the way the loads are introduced into the panels, as well as the buckling shape, have an important influence on the plate buckling capacity. A design method with buckling curves using a slenderness ratio based on effective tensile strength seems applicable for the design of glass panels. As a result of numerical simulations, recommendations for the future development of plate buckling curves for plate glass elements under compression are given. Stabilité des éléments porteurs en verre La tendance actuelle en architecture moderne pour des structures toujours plus élancées et légères requiert l'utilisation de nouveaux matériaux de construction. Le verre, un matériau longtemps utilisé comme élément de remplissage des fenêtres, a beaucoup plus à offrir eu égard à sa très haute résistance à la compression et à sa transparence. C'est pourquoi on cherche à étendre l'utilisation des feuilles de verre pour en faire des éléments porteurs tels que poteaux, poutres ou parois. Ces éléments étant très élancés, ils ont tendance à se ruiner par instabilité lorsqu'ils sont soumis à la compression (ruine par flambage, déversement ou voilement). Actuellement, il existe très peu de connaissances dans le domaine de la capacité portante des éléments structuraux en verre, et les méthodes de dimensionnement développées pour d'autres matériaux de construction (par exemple l'acier) se sont avérées difficiles à appliquer directement au…
... The main objective of research work being conducted is to develop a design method for stabili... more ... The main objective of research work being conducted is to develop a design method for stability-critical load carry-ing glass elements which may fail due to lack of stability, ie columnbuckling, plate buckling and lateral torsional buckling [2]. In this paper the most im-portant ...
ABSTRACT Due to the large increase of structural glass applications, the lateral torsional buckli... more ABSTRACT Due to the large increase of structural glass applications, the lateral torsional buckling behavior of glass beams actually represents a topic of great interest for researchers. Although several analytical models and design approaches exist in literature, various aspects complicate the realistic prediction of their typical out-of-plane response, especially if composed of two (or more) laminated glass sheets. Based on viscoelastic numerical results and predictions of a large experimental campaign of lateral torsional buckling tests performed on PVB and SG beams, the paper investigates the accuracy of existing analytical models in the prediction of the elastic critical load and load-lateral displacement path of these elements.
Modern cities face a climatic problem due to the high proportion of sealed surfaces that increase... more Modern cities face a climatic problem due to the high proportion of sealed surfaces that increase the urban heat island (UHI) effect. Green surfaces offer a way to mitigate the UHI effect, as they positively influence the thermal energy storage and air temperature. To support an increase of green surfaces in the limited resources of cities, vertical spaces, e.g. façades, must be exploited. A possible realisation of a vertical green system are overgrown rope façades. Overgrown rope façades have pre-fitted ropes in front of façades on which climbing plants can grow. However, such systems have to deal with dynamic wind forces, which pose static challenges to the climbing system. In order to design such systems for the effective wind forces, so-called drag coefficients of the climbing plants must be known. Unfortunately, there are no guidelines or known values that provide such specific drag coefficients for climbing plants. In this study, based on a study review of relevant data for dr...
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