Dr.-Ing.

Albrecht, Stefan

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Switchable Heat Pipes for Eco-Friendly Battery Cooling in Electric Vehicles: A Life Cycle Assessment

2024-02-17 , Illner, Maike , Thüsing, Kai , Nioac de Salles, Ana Claudia , Trettenhann, Anian , Albrecht, Stefan , Winkler, Markus

Battery thermal management systems (BTMSs) ensure that lithium-ion batteries (LIBs) in electric vehicles (EVs) are operated in an optimal temperature range to achieve high performance and reduce risks. A conventional BTMS operates either as an active system that uses forced air, water or immersion cooling, or as a complete passive system without any temperature control. Passive systems function without any active energy supply and are therefore economically and environmentally advantageous. However, today’s passive BTMSs have limited cooling performance, which additionally cannot be controlled. To overcome this issue, an innovative BTMS approach based on heat pipes with an integrated thermal switch, developed by the Fraunhofer Cluster of Excellence Programmable Materials (CPM), is presented in this paper. The suggested BTMS consists of switchable heat pipes which couple a passive fin-based cold plate with the battery cells. In cold state, the battery is insulated. If the switching temperature is reached, the heat pipes start working and conduct the battery heat to the cold plate where it is dissipated. The environmental benefits of this novel BTMS approach were then analysed with a Life Cycle Assessment (LCA). Here, a comparison is made between the suggested passive and an active BTMS. For the passive system, significantly lower environmental impacts were observed in nearly all impact categories assessed. It was identified as a technically promising and environmentally friendly approach for battery cooling in EVs of the compact class. Furthermore, the results show that passive BTMS in general are superior from an environmental point of view, due their energy self-sufficient nature

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Reusable Plastic Crates vs. Single-Use Cardboard Boxes

2022 , Albrecht, Stefan , Bertling, Jürgen , Fischer, Matthias , Gehring, Florian , Kabasci, Stephan , Prescher, Tim , Schulte, Anna

A.: Reusable plastic crates vs. single-use cardboard boxes-two packaging systems in competition, Oberhausen/Stuttgart 2022.

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The dilemma of balancing design for impact sound with environmental performance in wood ceiling systems - A building physics perspective

2021 , Müller, Theresa , Borschewski, David Sven , Albrecht, Stefan , Leistner, Philip , 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.

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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, 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).

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Sustainable Pultruded Sandwich Profiles with Mycelium Core

2023-07-28 , Früchtl, Marion , Senz, Andreas , Sydow, Steffen , Frank, Jonas Benjamin , Hohmann, Andrea , Albrecht, Stefan , Fischer, Matthias , Holland, Maximilian , Wilhelm, Frederik , Christ, Henrik-Alexander

This research focuses on exploring the potential of mycelium as a sustainable alternative to wood or solid foam in pultruded glass fiber-reinforced plastic (GFRP) sandwich profiles. The study evaluates the performance and the environmental sustainability potential of this composite by mechanical tests and life cycle assessment (LCA). Analysis and comparison of pultruded sandwich profiles with mycelium, polyurethane (PUR) foam and chipboard demonstrate that mycelium is competitive in terms of its performance and environmental impact. The LCA indicates that 88% of greenhouse gas emissions are attributed to mycelium production, with the heat pressing (laboratory scale) being the main culprit. When pultruded profiles with mycelium cores of densities 350 and 550 kg/m 3 are produced using an oil-heated lab press, a global warming potential (GWP) of 5.74 and 9.10 kg CO 2-eq. per functional unit was calculated, respectively. When using an electrically heated press, the GWP decreases to 1.50 and 1.78 kg CO 2-eq. Compared to PUR foam, a reduction of 23% in GWP is possible. In order to leverage this potential, the material performance and the reproducibility of the properties must be further increased. Additionally, an adjustment of the manufacturing process with in situ mycelium deactivation during pultrusion could further reduce the energy consumption.

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Sustainable Shape Memory Polymer Foams

2022 , Walter, Mario , Pretsch, Thorsten , Borschewski, David Sven , Albrecht, Stefan , Lengsfeld, Kristin , Mügge, Maximilian , Lehmann-Brauns, Susanne

Today, polymer foams are used in numerous industries such as automotive, consumer goods, construction, medical and aerospace. The thermal and mechanical properties of water-blown polyurethane (PUR) foams can be varied over a wide range, depending on the starting materials used to produce them. After thermomechanical treatment, also known as programming, certain PUR foams exhibit a self-sufficient switching behavior during heating and cooling. This can add value and enable new applications. Here, we introduce new polyurethane foams that are able to thermoreversibly change shape. This functionality, combined with good insulating properties, paves the way for novel concepts for material-inherent thermal management. By selecting the molecular building blocks, the switching temperature range and foam properties can be tailored. The sustainability of the materials can also be increased by customized formulations. Bio-based raw materials lead to a high proportion of renewable carbon, while the selection of linear building blocks enables the formation of thermoplastic polymers that can be mechanically recycled, for example. The ecological impact of such materials and the thermal management concepts based on them can be estimated with the aid of life cycle assessments. Financial support from Fraunhofer Cluster of Excellence Programmable Materials, grant number 40-03549-2500-00002, is kindly acknowledged.

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Environmental impacts of renewable insulation materials

2021 , Geß, Andreas , Lorenz, Manuel , Tolsdorf, Anna , Albrecht, S.

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.

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Reliability as a Key Driver for a Sustainable Design of Adaptive Load-Bearing Structures

2022-01-13 , Efinger, Dshamil , Ostertag, Andreas , Dazer, Martin , Borschewski, David Sven , 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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Mehrwegsteige aus Kunststoff vs. Einwegkarton aus Pappe

2022 , Albrecht, Stefan , Bertling, Jürgen , Fischer, Matthias , Gehring, Florian , Kabasci, Stephan , Prescher, Tim , Schulte, Anna

Weg vom Kunststoff hin zu Papier, Karton oder Pappe - wie nachhaltig ist der neue Verpackungstrend? In diesem Bericht erläutern das Fraunhofer-Institut für Umwelt-, Sicherheits- und Energietechnik UMSICHT und das Fraunhofer-Institut für Bauphysik IBP im Auftrag der Stiftung Initiative Mehrweg (SIM) Hintergründe und Zusammenhänge zu ökologischen Wirkungen des Einwegkartons und der Kunststoff-Mehrwegsteige. Ein darauf aufbauender genereller Diskurs zum Thema Einweg vs. Mehrweg soll Akteuren der Politik Hilfestellung geben, die richtigen Weichen für eine funktionierende Kreislaufwirtschaft der Zukunft zu stellen.

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Die Bedeutung von Anlagentechnik für die Ökobilanz von Nichtwohngebäuden - Ergebnisse eines neuen Anlagenkonfigurators

2020 , Chuchra, David , Bari, Roberta di , Jorgji, Olivia , Albrecht, Stefan

Gebäude leisten einen erheblichen Beitrag zur globalen Erwärmung, dem Ressourcenverbrauch und der Produktion von Abfällen. Mit verbesserten Energiestandards steigt der Anteil der Herstellung und des Lebensendes gebäudetechnischer Komponenten an den Umweltwirkungen des Lebenszyklus. Aufgrund der Komplexität liegt der Anteil gebäudetechnischer Komponenten an den gesamten Treibhausgasemissionen eines Gebäudes bei bis zu 25%. In den derzeit angewendeten Bewertungsverfahren werden die Verteilung und Übergabe oft vereinfacht oder nicht abgebildet. Es wurde daher ein Anlagenkonfigurator entwickelt, der flexibel im Planungsprozess eingesetzt werden kann und an die verfügbaren Informationen angepasst ist. Erste Ergebnisse zeigen, dass der Anteil der Verteil- und Übergabesysteme bis zu 80 % an den gesamten Treibhausgasemissionen einer Kostengruppe betragen kann und daher nicht wie bisher vernachlässigbar ist.

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