Publisher
Editorial
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Dear JFDE Readers and Authors,
After four volumes of JFDE we can conclude that JFDE is still being seen as a ‘young’ journal just as the scientific area it is aiming to serve. In the past, building envelope related papers have been published in structure or building physics related journals. But with the development of the professional field the scientific community grows as well, and with it JFDE is enjoying more and more acknowledgement.
One result is that we have been able to become the scientific partner of two conferences: ‘Powerskin’ in January 2017 at the BAU building trade fair in Munich and the ICBEST International Conference on Building Envelopes Systems and Technologies, May 2017 in Istanbul. Both events will be covered in two special issues.
This development stimulates us to continuously evaluate the future scope of JFDE. In this sense, we are proud to present a new issue of JFDE with innovative contributions that target both the design and engineering of building envelopes.
Two papers focus on a better understanding of facades in a technical sense. The first one predicts light transmission trough complex fenestration systems including high incident directions, the other aims at understanding the increased thermal load, the effect on structural safety of insulated glass units and the implications for norms and regulations.
Two other contributions focus on novel applications: The first one looks at photocatalytic self-cleaning coatings for building façade maintenance. The application of Nano technologies is rather new and it is important to explore the potential it might provide to the discipline. The second one researches biomimetic inspired natural ventilation facades with integrated green.
Such combination is prototypic of the scope we envision for JFDE. A good mixture of technical and innovative contributions, always trying to relate science and practice, design and engineering.
The editors in chief,
Tillmann Klein
Ulrich Knaack
Dear JFDE Readers and Authors,
After four volumes of JFDE we can conclude that JFDE is still being seen as a ‘young’ journal just as the scientific area it is aiming to serve. In the past, building envelope related papers have been published in structure or building physics related journals. But with the development of the professional field the scientific community grows as well, and with it JFDE is enjoying more and more acknowledgement.
One result is that we have been able to become the scientific partner of two conferences: ‘Powerskin’ in January 2017 at the BAU building trade fair in Munich and the ICBEST International Conference on Building Envelopes Systems and Technologies, May 2017 in Istanbul. Both events will be covered in two special issues.
This development stimulates us to continuously evaluate the future scope of JFDE. In this sense, we are proud to present a...
Dear JFDE Readers and Authors,
After four volumes of JFDE we can conclude that JFDE is still being seen as a ‘young’ journal just as the scientific area it is aiming to serve. In the past, building envelope related papers have been...
Articles
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The transmission and distribution of light through Complex Fenestration Systems (CFS) impacts visual comfort, solar gains and the overall energy performance of buildings. For most fenestration, scattering of light can be approximated as the optical property of a thin surface, the Bidirectional Scattering Distribution Function (BSDF). It is modelled in simulation software to replicate the optical behaviour of materials and surface finishes. Data-driven BSDF models are a generic means to model the irregular scattering by CFS employing measured or computed data-sets. While measurements are preferred by researchers aiming at realism, they are constraint by the measurement geometries of the employed instrumentation. Particularly for large samples prevailing in the field of building sciences, measurements of the BSDF for directions close to grazing are impacted by shadowing and edge effects. Reliable extrapolation techniques are not available due to the irregularity of the BSDF. Computational simulation is not limited by such constraints at the cost of lower realism. A hybrid approach is therefore proposed. The BSDF of a CFS is measured for incident elevation angles from 0° to 60°. For incident elevation angles from 0° to 85°, the BSDF of the sample is computed. The BSDF acquired by both techniques in the overlapping range of directions between 0° to 60° is compared and reveals good qualitative accordance. The variance of the direct-hemispherical reflection and transmission based on the two techniques is between 3% and 28%. A hybrid data-set is then generated, utilizing measurements where possible and simulations where instrumentation cannot provide reliable data. A data-driven model based on this data-set is implemented in simulation software. This hybrid model is tested by comparison with the geometrical model of the sample. The hybrid approach to BSDF modelling shall support the utilization of BSDF models based on measured data by selectively overcoming the lack of reliable measured or extrapolated data.
The transmission and distribution of light through Complex Fenestration Systems (CFS) impacts visual comfort, solar gains and the overall energy performance of buildings. For most fenestration, scattering of light can be approximated as the optical property of a thin surface, the Bidirectional Scattering Distribution Function (BSDF). It is modelled in simulation software to replicate the optical behaviour of materials and surface finishes. Data-driven BSDF models are a generic means to model the irregular scattering by CFS employing measured or computed data-sets. While measurements are preferred by researchers aiming at realism, they are constraint by the measurement geometries of the employed instrumentation. Particularly for large samples prevailing in the field of building sciences, measurements of the BSDF for directions close to grazing are impacted by shadowing and edge effects. Reliable extrapolation techniques are not available due to the irregularity of...
The transmission and distribution of light through Complex Fenestration Systems (CFS) impacts visual comfort, solar gains and the overall energy performance of buildings. For most fenestration, scattering of light can be approximated as the optical property of a thin surface,...
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The oil crises of the 1970s increased the awareness of energy efficiency. Over the past forty years, single- and double-glazed windows have evolved into a range of modern insulating glass solutions for windows and facades. In the mid-1990s the climatic loading of double-glazed units (DGUs) was investigated and design rules were developed for use in practice. Even though those rules were at the time developed for DGUs, they have recently also been used for the design of modern triple-glazed units (TGUs) and multilayer facade systems. So far, no research has posed the question whether this design process, and in particular the temperature differences that have been determined for DGUs, can be applied to other systems. It is therefore the aim of this paper to determine the governing temperatures in insulated glass units (IGUs) under modern boundary conditions. To do this, the thermal behavior of TGUs, multilayer facade systems and solar shading is investigated in detail. A simple calculation model is developed, which can be used to determine the glass temperatures in various facade configurations in accordance with the relevant standards. The results show that while parts of the existing requirements are still valid, there are distinct differences in the requirements for more modern applications.
The oil crises of the 1970s increased the awareness of energy efficiency. Over the past forty years, single- and double-glazed windows have evolved into a range of modern insulating glass solutions for windows and facades. In the mid-1990s the climatic loading of double-glazed units (DGUs) was investigated and design rules were developed for use in practice. Even though those rules were at the time developed for DGUs, they have recently also been used for the design of modern triple-glazed units (TGUs) and multilayer facade systems. So far, no research has posed the question whether this design process, and in particular the temperature differences that have been determined for DGUs, can be applied to other systems. It is therefore the aim of this paper to determine the governing temperatures in insulated glass units (IGUs) under modern boundary conditions. To do this, the thermal behavior of TGUs, multilayer facade systems and solar shading is investigated in detail. A simple...
The oil crises of the 1970s increased the awareness of energy efficiency. Over the past forty years, single- and double-glazed windows have evolved into a range of modern insulating glass solutions for windows and facades. In the mid-1990s the climatic loading of double-glazed units (DGUs) was...
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Façade maintenance has become a key aspect in building management, due the specific actions involved and operation related costs. In this frame, the application of titanium dioxide photocatalytic sol-gel products on façade elements offers a wide range of opportunities to ensure proper functionalities maintenance overtime. This paper illustrates the self-cleaning performance of titanium dioxide and silicon dioxide based coatings applied to different kind of cladding materials. All tested samples were opaque. Preliminary laboratory tests were performed to verify hydrophobic and hydrophilic behaviour, prior to outdoor application, through water contact angle measurements. Afterwards, outdoor tests were performed to monitor color variation during 36 months to verify product effectiveness and its durability. Results proved that the application of functionalized nanotechnological coating to façade can significantly ease cleaning operations and reduce their necessary frequency over time. In addition, output provide some preliminary information about exposure condition influence on self-cleaning performance, which could be further investigated in the future.
Façade maintenance has become a key aspect in building management, due the specific actions involved and operation related costs. In this frame, the application of titanium dioxide photocatalytic sol-gel products on façade elements offers a wide range of opportunities to ensure proper functionalities maintenance overtime. This paper illustrates the self-cleaning performance of titanium dioxide and silicon dioxide based coatings applied to different kind of cladding materials. All tested samples were opaque. Preliminary laboratory tests were performed to verify hydrophobic and hydrophilic behaviour, prior to outdoor application, through water contact angle measurements. Afterwards, outdoor tests were performed to monitor color variation during 36 months to verify product effectiveness and its durability. Results proved that the application of functionalized nanotechnological coating to façade can significantly ease cleaning operations and reduce their necessary frequency over...
Façade maintenance has become a key aspect in building management, due the specific actions involved and operation related costs. In this frame, the application of titanium dioxide photocatalytic sol-gel products on façade elements offers a wide range of opportunities to ensure proper...
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This paper deals with the greening of claddings and the cooling of buildings from the perspective of a bionic scientist or an industrial designer. Reflections on a new building cover shall early enough show an approach to the containment of future problems in the often predicted ‘urban future’. The development of a concept for a greened cooling cladding happens through the transition of bionic-mathematical principles, which have been considered only a little here so far. The paper begins with a summary of the public debate about the topics urbanization and climate change. The section 'greening of claddings' shall illustrate a smarter, future-orientated idea for the building sector. The section of architectural bionics shows the potentials of nature’s principles of construction, originating millions of years ago, and it analyses relevant bionic principles in full detail. To conclude, the author’s iterative concept development for a bionically-mathematically inspired, greened cooling cladding is explained and the obtained findings are discussed. In addition, further development potentials are considered.
This paper deals with the greening of claddings and the cooling of buildings from the perspective of a bionic scientist or an industrial designer. Reflections on a new building cover shall early enough show an approach to the containment of future problems in the often predicted ‘urban future’. The development of a concept for a greened cooling cladding happens through the transition of bionic-mathematical principles, which have been considered only a little here so far. The paper begins with a summary of the public debate about the topics urbanization and climate change. The section 'greening of claddings' shall illustrate a smarter, future-orientated idea for the building sector. The section of architectural bionics shows the potentials of nature’s principles of construction, originating millions of years ago, and it analyses relevant bionic principles in full detail. To conclude, the author’s iterative concept development for a bionically-mathematically...
This paper deals with the greening of claddings and the cooling of buildings from the perspective of a bionic scientist or an industrial designer. Reflections on a new building cover shall early enough show an approach to the containment of future problems in the often predicted...