Dr.-Ing.

Albrecht, Stefan

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  • Publication
    Reliability as a Key Driver for a Sustainable Design of Adaptive Load-Bearing Structures
    ( 2022)
    Efinger, D.
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    Ostertag, A.
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    Dazer, M.
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    Borschewski, D.
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    Albrecht, S. orcid-logo
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    Bertsche, B.
    The consumption of construction materials and the pollution caused by their production can be reduced by the use of reliable adaptive load-bearing structures. Adaptive load-bearing structures are able to adapt to different load cases by specifically manipulating internal stresses using actuators installed in the structure. One main aspect of quality is reliability. A verification of reliability, and thus the safety of conventional structures, was a design issue. When it comes to adaptive load-bearing structures, the material savings reduce the stiffness of the structure, whereby integrated actuators with sensors and a control take over the stiffening. This article explains why the conventional design process is not sufficient for adaptive load-bearing structures and proposes a method for demonstrating improved reliability and environmental sustainability. For this purpose, an exemplary adaptive load-bearing structure is introduced. A linear elastic model, simulating ten sion in the elements of the adaptive load-bearing structure, supports the analysis. By means of a representative local load-spectrum, the operating life is estimated based on Woehler curves given by the Eurocode for the critical notches. Environmental sustainability is increased by including reliability and sustainability in design. For an exemplary high-rise adaptive load-bearing structure, this increase is more than 50%.
  • Publication
    Plastik-Index PLIX macht Verpackungen vergleichbar
    ( 2021)
    Adel, F. van den
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    Scagnetti, C.
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    Lorenz, M.
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    Krieg, H.
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    Albrecht, S. orcid-logo
    Der Plastik-Index (PLIX) bietet Konsumierenden und Unternehmen ein verständliches Instrument zur Bewertung von Kunststoffverpackungen und zum Vergleich von Kunststoffverpackungen. Der PLIX befähigt Konsumierende, ihren Verpackungsverbrauch zu reduzieren und Unternehmen in Handel und Logistik, ihren gesamten ökologischen Fußabdruck zu minimieren. Die Bewertungskriterien für den PLIX sind die Verpackungsmenge, die Rezyklierfähigkeit und deren Umweltwirkung; die daraus resultierende Bewertung wird in einem ""best case"" bis ""worst case"" Szenario dargestellt. Unter Berücksichtigung des Lebenszyklusgedankens wird die Verpackung von ""Cradle to Gate"", also vom Rohstoffabbau bis zum Point of Sale im Einzelhandel berücksichtigt. In der vorliegenden Fallstudie dient der PLIX als Instrument zum Vergleich verschiedener Verpackungen innerhalb der Produktgruppe Tomaten. Grundsätzlich ist der PLIX jedoch auch für Anwendungsfälle außerhalb des Lebensmittelbereiches geeignet.
  • Publication
    The dilemma of balancing design for impact sound with environmental performance in wood ceiling systems - A building physics perspective
    ( 2021)
    Müller, Theresa
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    Borschewski, David Sven
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    Albrecht, Stefan orcid-logo
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    Leistner, Philip
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    Späh, Moritz
    Due to the high consumption of resources and energy in the construction sector, the development of resource-efficient and sustainable construction solutions is gaining increasing attention. The awareness of sustainability and resource conservation results in the interest of using natural and renewable materials in contemporary architecture. Timber construction methods offer both constructive and ecological potential for sustainable solutions. From a building physics perspective, the acoustic performance of lightweight buildings, such as those made of timber, presents a challenge. Even if standard requirements are met, the increased low-frequency sound transmission typical for light-weight construction can cause discomfort and is already the subject of questions in building physics, which are currently increasingly extending to timber construction. Within the framework of a holistic approach, this paper compares the problem of acoustic properties, design optimizations and the ecological properties of timber-frame and solid timber construction components. The comparison with heavy materials, such as concrete, shows the relation of acoustic optimization with the change of the environmental profile. In order to establish the interaction between acoustic quality of wooden ceiling constructions and their ecological characteristics, this article aims to demonstrate the potential of materials used in the building sector under ecological aspects considering a life cycle analysis.
  • Publication
    Environmental impacts of renewable insulation materials
    ( 2021)
    Geß, Andreas
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    Lorenz, Manuel
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    Tolsdorf, Anna
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    Albrecht, S. orcid-logo
    According to the IEA Global Status Report for Buildings and Construction 2019, one of the main industry sectors causing environmental impacts is the construction sector. Hence, construction materials from renewable resources are expected to have a large potential to decrease these impacts. In this study, a Life Cycle Assessment (LCA) was conducted for four different insulation materials from renewable feedstock: insulation made from pasture grass, seaweed, reed, and recycled jute fibres. Additionally, the effects on land use change were evaluated for pasture grass insulation using the LANCA® methodology. To put the LCA results in relation to those of nonrenewable resources, a comparison of standardized LCA values for conventional insulation materials is presented. In general, the renewable insulation materials show fewer environmental impacts than their conventional counterparts. In particular, these materials have advantages regarding greenhouse gas emissions and their impact on climate change. Of the analyzed materials, seaweed showed the overall lowest emissions. It can be concluded that insulation materials from non-mineral, non-fossil, and non-wooden resources are still fairly niche in terms of market share, but they have extraordinary potential in decreasing the environmental impacts of construction ventures.
  • Publication
    Zu Ende gedacht bewerten. Integration nachhaltiger Faktoren in die Bewertung von Investitionsobjekten
    ( 2020)
    Ilg, Robert
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    Albrecht, Stefan orcid-logo
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    Fischer, Matthias orcid-logo
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    Wimmer, Konrad
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    Ender, Manuela
    Die COVID-19-Pandemie und ihre Folgen haben die Transformation der Gesellschaft und Wirtschaft hin zu mehr Nachhaltigkeit auf den ersten Blick verzögert, wenn nicht gar gebremst. Auf der Tagesordnung fanden sich im ersten Halbjahr 2020 dringlichere Punkte. Auf den zweiten Blick stellt man jedoch fest, dass die Entwicklung sogar Fahrt aufgenommen hat. Mehr noch: Die gewaltigen Finanzmittel, die die Politik in den ""Wiederaufbau"" investieren wird, um die wirtschaftlichen Pandemieeffekte zu mildern beziehungsweise zu kompensieren, entpuppen sich als eine entscheidende Weichenstellung. Ziel muss es sein, die Finanzströme in erster Linie in nachhaltige Investitionsobjekte zu lenken. Die Szenarien auf die weltweite BIP-Entwicklung, die das ""Network for Greening the Financial System""(NGFS) im Juni 2020 vorlegt, sind beeindruckend und bedrückend genug (vgl. Abbildung 1: ""Orderly"" beziehungsweise ""Disorderly"" stehen für rechtzeitiges geordnetes politisches Handeln beziehungsweise für einen verzögerten Start ab 2030; ""Hot house world"" entspricht dem bloßen Fortschreiben bisheriger Maßnahmen mit der Folge der Erwärmung um plus drei Prozent bis 2080). Die Kreditwirtschaft nimmt ganz offensichtlich eine Schlüsselrolle bei der Transformation ein, da die Kreditvergabeentscheidung ausgezeichnet geeignet ist, zwischen - plakativ formuliert - grünen und grauen Investitionen zu selektieren. Letztere sollten abgelehnt oder mit einem hohen Zinsaufschlag versehen werden. Diese Preisgestaltung ist überdies aus betriebswirtschaftlicher Sicht zwingend notwendig, denn bei den grauen Investitionen drohen hohe Kreditausfällein der Zukunft.
  • Publication
    LCA of buildings in Germany: Proposal for a future benchmark based on existing databases
    ( 2019)
    Schlegl, Friederike
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    Gantner, Johannes
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    Traunspurger, René
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    Albrecht, Stefan orcid-logo
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    Leistner, Philip
    The evaluation of environmental aspects in the early planning phase of buildings can support the reduction of the resource use and environmental impacts associated with the building sector over the whole building life-cycle. The integration of life cycle assessment (LCA) benchmarks in the planning phase is one potential measure. To derive these benchmarks a large database of existing building assessment is essential. Potential data input is available from the German Sustainable Building Council (DGNB), as it certifies more than 200 buildings annually and the certification includes a mandatory LCA. In this study, the current submission files and database of the DGNB are assessed and critically reviewed with regard to their usability for automated LCA benchmarks. First, a harmonized database is created from the large number of assessed buildings. Second, the data is examined for its suitability for benchmarking with regard to data format, structure and level of detail. The data that were declared fit for purpose were used to create an exemplary, harmonized data set with 22 office buildings. The evaluation of these data for various environmental indicators of the individual life-cycle phases shows their respective relevance and can thus serve as a benchmark. Another focus is to encourage improvement of the additional documentation like the energy source required for better benchmarking, interpretation of results and auditing of the LCA rules for building certification. The results of this study highlight the opportunities and challenges in the development of a database for benchmarking. Before long-term LCA benchmarks can be developed and deployed, a standardized and uniform submission format of results, that is indifferent regarding the used LCA software, needs to be developed. In the future the submission process should be extended by an automated quality assurance to prevent restraints from low data quality and data gaps that otherwise have to be detected manually.
  • Publication
    Bauphysikalische und ökologische Bewertung adaptiver Fassadenkonstruktionen auf Raumebene
    ( 2019)
    Harder, Nadine
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    Schlegl, Friederike
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    Flemming, Daniela
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    Bari, Roberta di
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    Albrecht, Stefan orcid-logo
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    Leistner, Philip
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    Park, Sumee
    Eine Antwort auf den großen und fortschreitenden Ressourcenverbrauch im Bauwesen können leichte und zugleich adaptive Lösungsansätze für Gebäudehüllen und -strukturen darstellen. Dazu müssen sie sowohl für schadensfreie Bauwerke mit passender Aufenthaltsqualität als auch für eine deutlich höhere Ressourceneffizienz sorgen. Beides gilt für den gesamten Lebensweg und trotz der für die Adaptivität benötigen zusätzlichen Betriebsenergie. Im Rahmen einer vorangegangenen Untersuchung adaptiver Leichtbaukonstruktionen für Fassaden wurde die bauphysikalische Funktionalität und Umweltwirkung einiger Beispiele auf Bauteilebene behandelt. Im hier vorliegenden Beitrag wird nun der Betrachtungshorizont auf die Raumebene erweitert, um z. B. neben Kennwerten für Wärme- und Feuchteschutz der Hülle auch die Behaglichkeit im Raum als Bewertungsmaßstab heranzuziehen. Natürlich erhöhen sich damit der Aufwand und die Komplexität der Bilanz, dafür lässt sich aber fundierter das Anwendungspotenzial adaptiver Alternativen einschätzen und über deren Weiterverfolgung entscheiden. Dazu werden drei herkömmliche, teils massive und teils leichte Konstruktionen, sowie vergleichbare adaptive Fassaden auf Raumebene untersucht und bewertet. Als wesentliche Bewertungskriterien gelten dabei quantitative Aussagen zur Erfüllung bauphysikalischer Anforderungen und zu ökologischen Umweltwirkungen. Im Ergebnis der methodenübergreifenden Forschung zeigt sich, dass adaptive Konstruktionen fallspezifisch, z. B. standortbezogen, beachtliches Potenzial zur Ressourcenreduktion ohne Funktionseinschränkungen mit sich bringen.
  • Publication
    Bio-inspiration as a Concept for Sustainable Constructions Illustrated on Graded Concrete
    ( 2019)
    Horn, Rafael
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    Albrecht, Stefan orcid-logo
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    Haase, Walter
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    Langer, Max
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    Schmeer, Daniel
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    Sobek, Werner
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    Speck, Olga
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    Leistner, Philip
    The building industry is one of the main contributors to worldwide resource consumption and anthropogenic climate change. Therefore, sustainable solutions in construction are particularly urgent. Inspired by the success principles of living nature, biologists and engineers present here an interdisciplinary work: The sustainability assessment of a bio-inspired material technology called graded concrete, which was developed at ILEK. Gradient structural materials can be found in plants on different hierarchical levels, providing a multitude of creative solutions for technology. Graded concrete applies this biological concept of structural optimization to the interior structure of concrete components to minimize material and resource expenditure. To evaluate the sustainability of this innovation, a newly developed quantitative Bio-inspired Sustainability Assessment (BiSA) method is applied. It focuses on the relationship of environmental, social and economic functions and the corresponding burdens quantified basing on life cycle assessment. The BiSA of graded concrete slabs shows significant improvements over conventional concrete for the applied use case. While an overall reduction of environmental burdens by 13% is expected, economic burdens can be reduced by up to 40% and social burdens by 35.7%. The assessment of the graded concrete technology identifies its potential with regard to sustainable construction. The presented work provides a blueprint for the interdisciplinary, integrative work on sustainable, bio-inspired innovations. It shows that the synergies of bio-inspiration and BiSA within technical product development can be fruitful.
  • Publication
    Integration of LCA in the planning phases of adaptive buildings
    ( 2019)
    Schlegl, Friederike
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    Honold, Clemens
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    Leistner, Sophia
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    Albrecht, Stefan orcid-logo
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    Roth, Daniel
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    Haase, Walter
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    Leistner, Philip
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    Binz, Hansgeorg
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    Sobek, W.
    The high consumption of resources in the building industry requires a significant reduction of material in buildings and consequently a reduction of emissions over all phases of the life cycle. This is the aim of the Collaborative Research Centre 1244 Adaptive Skins and Structures for the Built Environment of Tomorrow, funded by the German Research Foundation (DFG), which addresses research on the development and integration of adaptive systems in building structures and skins. New approaches in building planning are required for the implementation of adaptive buildings. Therefore, a multidisciplinary team from various fields such as architecture, civil and mechanical engineering, and system dynamics is necessary. The environmental impacts of the whole life cycle have to be considered for an integral planning process for adaptive buildings right from the beginning. For the integration of the Life Cycle Assessment (LCA), four temporal and content-related interfaces were identified in the planning process. Inputs and outputs of the LCA were defined for the relevant planning stages in order to enable the greatest possible benefit for the planners and to minimize the environmental impacts as far as possible. The result of the research work is a methodology that can be used in the future to reduce life cycle-related environmental impacts in the planning process of adaptive buildings (ReAdapt).