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    Managing uncertainties in LCA dataset selection
    (2019) Pfeuffer, Simon; Wehner, Daniel; Bouslama, Raed
    The selection of LCA datasets requires an understanding of the available datasets in a database and awareness about the uncertainties associated with the dataset selection. Therefore, a graphical presentation technique is introduced to support the communication of information about available datasets and uncertainties.
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    Reliability as a key driver for a sustainable design of adaptive load-bearing structures
    (2022) Efinger, Dshamil; Ostertag, Andreas; Dazer, Martin; Borschewski, David; Albrecht, Stefan; Bertsche, Bernd
    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 tension 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%.
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    The relevance of recyclability for the life cycle assessment of packaging based on Design for Life Cycle
    (2022) Keller, Jonas; Scagnetti, Carla; Albrecht, Stefan
    The awareness for more environmentally sustainable packaging solutions is steadily growing. With both consumers and manufacturers looking to minimize their impacts on the environment, the need for easy-to-implement and standardized measures strengthening a circular economy rises. In the research, the goal was to determine whether the carbon footprint and circularity of non-food plastic packaging can be improved by simple design changes. The results should then lead to design recommendations, providing a Design for Life Cycle approach. The methodology of the study was to conceptually design a single-use plastic packaging with attributes having positive and negative effects on recyclability. Herein, only design characteristics from products obtainable on the market were regarded. Moreover, a comparison over existing recyclability assessment methods is given. The recyclability was then determined with the selected approach by Cyclos HTP, and a reference calculation was conducted. Life Cycle Assessments were implemented for 14 packaging designs using the GaBi software and the Environmental Footprint method. The results showed that dark color, material compounds, insoluble adhesives, and large labels result in lower recyclability of the single-use packaging. The impacts on climate change range from 0.13 kg CO2-equivalent emissions (100% recyclability) to 0.21 kg CO2-equivalent emissions (0% recyclability) per packaging, showing that lower recyclability leads to a larger carbon footprint in all assessed scenarios. Concluding, the research demonstrated that by applying Design for Life Cycle measures, impacts on climate change can be reduced. Lastly, design recommendations for decision makers are outlined.
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    Grill and chill: a comprehensive analysis of the environmental impacts of private household barbecuing in Germany
    (2024) Geng, Shaoran; Dorling, Kevin Christopher; Prenzel, Tobias Manuel; Albrecht, Stefan
    Rising environmental consciousness has prompted increased scrutiny of the environmental impact of everyday activities, such as barbecuing - a popular summertime activity in Germany. This study aimed to explore the environmental impacts of three grilling techniques, charcoal (including reusable types such as swivel, round, and kettle grills, as well as disposable charcoal grills), gas, and electric grills, utilizing a life cycle assessment (LCA) approach including the manufacturing of grills, consumption of energy sources and grilling ingredients, as well as the end-of-life of the grills. Five impact categories were considered: global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), abiotic depletion potential fossil (ADP), and land use (LU) according to the CML2016 and ReCiPe 2016 methodology. This study found that a barbeque event for four people results in GWP, AP, EP, ADP, and LU values ranging from 18 to 20 kg CO2-eq., 174 to 179 g SO2-eq., 166 to 167 g PO4-eq., 102 to 138 MJ, and 36 to 38 m2 annual crop-eq., respectively, across different types of grills. Furthermore, the ingredients proved to be the most significant contributor, surpassing 70% in all impact categories. Among the three types of grills, the electric grill emerged as the most environmentally friendly, while the disposable grill had the greatest environmental impact across the majority of categories. Lastly, the environmental impacts of varying consumer behaviors were evaluated to potentially assist consumers in adopting more sustainable grilling practices.
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    Analysis of the microclimatic and biodiversity-enhancing functions of a living wall prototype for more-than-human conviviality in cities
    (2023) Bornschlegl, Sebastian; Krause, Pia; Kropp, Cordula; Leistner, Philip
    This study analyzes the growing trend of urban green infrastructures, particularly green façade systems, in terms of their infrastructural relationships between nature and culture and their potential to act as bioclimatic layers mediating between the needs of flora, fauna and human habitation. An interdisciplinary approach is taken by combining the perspectives of social and engineering sciences to discuss the contribution of green façade systems for more-than-human conviviality in cities. Green infrastructures can support this endeavor by enabling functions that help to integrate the heterogeneity typical for semi-natural structures into urban ones, especially regarding microclimatic and biodiversity-enhancing functions. The theoretical distinction between “gray”, “green”, and “revolutionary” infrastructure is used to differentiate between conventional and posthumanist conceptualizations of urban naturecultures. The performance of the UNA TERRA living wall prototype as a green and revolutionary infrastructure is evaluated. The results show that the living wall has beneficial microclimatic effects and adds a heterogeneous habitat structure that supports biodiversity in the urban context. By adhering to “egalitarian humility” in design, the uncertainty and openness of more-than-human conviviality are acknowledged. The study finds that green infrastructures such as green façade systems can fulfill the criteria of revolutionary infrastructure if the contribution to local biodiversity and structural complexity is prioritized and the heterogeneous interrelations between human and non-human actors are taken into account.
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    Integration of LCA in the planning phases of adaptive buildings
    (2019) Schlegl, Friederike; Honold, Clemens; Leistner, Sophia; Albrecht, Stefan; Roth, Daniel; Haase, Walter; Leistner, Philip; Binz, Hansgeorg; Sobek, Werner
    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).
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    Bringing light into the dark : overview of environmental impacts of carbon fiber production and potential levers for reduction
    (2023) Prenzel, Tobias Manuel; Hohmann, Andrea; Prescher, Tim; Angerer, Kerstin; Wehner, Daniel; Ilg, Robert; Reden, Tjark von; Drechsler, Klaus; Albrecht, Stefan
    Carbon fibers (CFs) are a crucial material for lightweight structures with advanced mechanical performance. However, there is still a paucity of detailed understanding regarding the environmental impacts of production. Previously, mostly singled-out scenarios for CF production have been assessed, often based on scarce transparent inventory data. To expand the current knowledge and create a robust database for future evaluation, a life cycle assessment (LCA) was carried out. To this end, a detailed industry-approved LCI is published, which also proved plausible against the literature. Subsequently, based on a global scenario representing the market averages for precursor and CF production, the most relevant contributors to climate change (EF3.1 climate change, total) and the depletion of fossil energy carriers (EF3.1 resource use, fossil) were identified. The energy consumption in CF manufacturing was found to be responsible for 59% of the climate change and 48% of the fossil resource use. To enable a differentiated discussion of manufacturing locations and process energy consumption, 24 distinct scenarios were assessed. The findings demonstrate the significant dependence of the results on the scenarios’ boundary conditions: climate change ranges from 13.0 to 34.1 kg CO2 eq./kg CF and resource use from 262.3 to 497.9 MJ/kg CF. Through the investigated scenarios, the relevant reduction potentials were identified. The presented results help close an existing data gap for high-quality, regionalized, and technology-specific LCA results for the production of CF.