02 Fakultät Bau- und Umweltingenieurwissenschaften

Permanent URI for this collectionhttps://elib.uni-stuttgart.de/handle/11682/3

Browse

Search Results

Now showing 1 - 10 of 25

Open Access
Sustainability assessment of fuel cell buses in public transport
(2018) Lozanovski, Aleksandar; Whitehouse, Nicole; Ko, Nathanael; Whitehouse, Simon
Hydrogen fuel cell (H2FC) buses operating in every day public transport services around Europe are assessed for their sustainability against environmental, economic and social criteria. As part of this assessment the buses are evaluated against diesel buses both in terms of sustainability and in terms of meeting real world requirements with respect to operational performance. The study concludes that H2FC buses meet operability and performance criteria and are sustainable environmentally when ‘green’ hydrogen is used. The economic sustainability of the buses, in terms of affordability, achieves parity with their fossil fuel equivalent by 2030 when the indirect costs to human health and climate change are included. Societal acceptance by those who worked with and used the buses supports the positive findings of earlier studies, although satisfactory operability and performance are shown to be essential to positive attitudes. Influential policy makers expressed positive sentiments only if ‘green’ hydrogen is used and the affordability issues can be addressed. No “show-stopper” is identified that would prevent future generations from using H2FC buses in public transport on a broad scale due to damage to the environment or to other factors that impinge on quality of life.
Open Access
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.
Open Access
Life cycle assessment for early-stage process optimization of microbial biosurfactant production using kinetic models : a case study on mannosylerythritol lipids (MEL)
(2024) Bippus, Lars; Briem, Ann-Kathrin; Beck, Alexander; Zibek, Susanne; Albrecht, Stefan
Introduction: This study assesses the environmental impacts of mannosylerythritol lipids (MELs) production for process optimization using life cycle assessment (LCA). MELs are glycolipid-type microbial biosurfactants with many possible applications based on their surface-active properties. They are generally produced by fungi from the family of Ustilaginaceae via fermentation in aerated bioreactors. The aim of our work is to accompany the development of biotechnological products at an early stage to enable environmentally sustainable process optimization. Methods: This is done by identifying hotspots and potentials for improvement based on a reliable quantification of the environmental impacts. The production processes of MELs are evaluated in a cradle-to-gate approach using the Environmental Footprint (EF) 3.1 impact assessment method. The LCA model is based on upscaled experimental data for the fermentation and purification, assuming the production at a 10 m³ scale. In the case analyzed, MELs are produced from rapeseed oil and glucose, and purified by separation, solvent extraction, and chromatography. Results: The results of the LCA show that the provision of substrates is a major source of environmental impacts and accounts for 20% of the impacts on Climate Change and more than 70% in the categories Acidification and Eutrophication. Moreover, 33% of the impacts on Climate Change is caused by the energy requirements for aeration of the bioreactor, while purification accounts for 42% of the impacts respectively. For the purification, solvents are identified as the main contributors in most impact categories. Discussion: The results illustrate the potentials for process optimization to reduce the environmental impacts of substrate requirements, enhanced bioreactor aeration, and efficient solvent use in downstream processing. By a scenario analysis, considering both experimental adaptations and prospective variations of the process, the laboratory development can be supported with further findings and hence efficiently optimized towards environmental sustainability. Moreover, the presentation of kinetic LCA results over the fermentation duration shows a novel way of calculating and visualizing results that corresponds to the way of thinking of process engineers using established environmental indicators and a detailed system analysis. Altogether, this LCA study supports and demonstrates the potential for further improvements towards more environmentally friendly produced surfactants.
Open Access
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.
Open Access
Insect habitat systems integrated into façades : impact on building physics and awareness of society
(2020) Meier, Linda; Raps, Johanna; Leistner, Philip
Deforestation, intensive farming and the sealing of green spaces are considered to be the main reasons for the global decrease of biodiversity. In this context, the built environment, and in particular vertical surfaces, are still highly underestimated and need to be taken into account. Although it is acknowledged that greened surfaces have beneficial effects, for example, on the microclimate, the vast majority of buildings are still not biodiversity-friendly. Artificial nesting boxes help birds and bats adapt to the change of their habitats. However, insects, with their tremendous significance for insectivorous species and for humans, are mostly neglected or even threatened. The purpose of this holistic approach is to investigate interactions between integrated insect habitat systems in façades and building physical aspects to create test objects. Heat transfer coefficients, thermal bridges, and the risk of condensation inside the buildings were simulated in different arrangements of nesting boxes for wild bees. As a result, conclusions on heat and humidity protection in ventilated façades and external thermal insulation composite systems could be drawn. The following results showed the maintenance of indoor comfort and energy efficiency as well as a low risk of mold. Further investigations analyzed the sound reduction index and fire protection. From a building physical point of view, integrated insect habitat systems could be part of the constructed environment and even link inner-city biotopes. Further challenges and opportunities are identified rather at a socio-ecological and technical level. Without taking into account the civil society and ecological demands of the various species, habitat systems for insects will miss their objectives. Special focus will be put on the skepticism and lack of knowledge of people, as well as on the comfort of the insects.
Open Access
Moving beyond land use intensity types : assessing biodiversity impacts using fuzzy thinking
(2021) Lindner, Jan Paul; Eberle, Ulrike; Knuepffer, Eva; Coelho, Carla R. V.
The impact of land use on biodiversity is a topic that has received considerable attention in life cycle assessment (LCA). The methodology to assess biodiversity in LCA has been improved in the past decades. This paper contributes to this progress by building on the concept of conditions for maintained biodiversity. It describes the theory for the development of mathematical functions representing the impact of land uses and management practices on biodiversity. The method proposed here describes the impact of land use on biodiversity as a decrease in biodiversity potential, capturing the impact of management practices. The method can be applied with weighting between regions, such as ecoregions. The biodiversity potential is calculated through functions that describe not only parameters which are relevant to biodiversity, for example, deadwood in a forest, but also the relationships between those parameters. For example, maximum biodiversity would hypothetically occur when the nutrient balance is ideal and no pesticide is applied. As these relationships may not be readily quantified, we propose the use of fuzzy thinking for biodiversity assessment, using AND/OR operators. The method allows the inclusion of context parameters that represent neither the management nor the land use practice being investigated, but are nevertheless relevant to biodiversity. The parameters and relationships can be defined by either literature or expert interviews. We give recommendations on how to create the biodiversity potential functions by providing the reader with a set of questions that can help build the functions and find the relationship between parameters. We present a simplified case study of paper production in the Scandinavian and Russian Taiga to demonstrate the applicability of the method. We apply the method to two scenarios, one representing an intensive forestry practice, and another representing lower intensity forestry management. The results communicate the differences between the two scenarios quantitatively, but more importantly, are able to provide guidance on improved management. We discuss the advantages of this condition-based approach compared to pre-defined intensity classes. The potential drawbacks of defining potential functions from industry-derived studies are pointed out. This method also provides a less strict approach to a reference situation, consequently allowing the adequate assessment of cases in which the most beneficial biodiversity state is achieved through management practices. The originality of using fuzzy thinking is that it enables land use management practices to be accounted for in LCA without requiring sub-categories for different intensities to be explicitly established, thus moving beyond the classification of land use practices. The proposed method is another LCIA step toward closing the gap between land use management practices and biodiversity conservation goals.
Open Access
Environmental impacts of renewable insulation materials
(2021) Geß, Andreas; Lorenz, Manuel; Tolsdorf, Anna; Albrecht, Stefan
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 non-renewable 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.
Open Access
Techno-economic feasibility of off-grid renewable energy electrification schemes : a case study of an informal settlement in Namibia
(2022) Amupolo, Aili; Nambundunga, Sofia; Chowdhury, Daniel S. P.; Grün, Gunnar
This paper examines different off-grid renewable energy-based electrification schemes for an informal settlement in Windhoek, Namibia. It presents a techno-economic comparison between the deployment of solar home systems to each residence and the supplying power from either a centralized roof-mounted or ground-mounted hybrid microgrid. The objective is to find a feasible energy system that satisfies technical and user constraints at a minimum levelized cost of energy (LCOE) and net present cost (NPC). Sensitivity analyses are performed on the ground-mounted microgrid to evaluate the impact of varying diesel fuel price, load demand, and solar photovoltaic module cost on system costs. HOMER Pro software is used for system sizing and optimization. The results show that a hybrid system comprising a solar photovoltaic, a diesel generator, and batteries offers the lowest NPC and LCOE for both electrification schemes. The LCOE for the smallest residential load of 1.7 kWh/day and the largest microgrid load of 5.5 MWh/day is USD 0.443/kWh and USD 0.380/kWh, respectively. Respective NPCs are USD 4738 and USD 90.8 million. A sensitivity analysis reveals that variation in the fuel price and load demand changes linearly with system costs and capacities. However, reducing the PV module price in an energy system that includes wind and diesel power sources does not offer significant benefits. Furthermore, deploying an energy system that relies on fossil fuels to each residence in an informal settlement is not environmentally responsible. Unintended negative environmental impacts may result from the mass and simultaneous use of diesel generators. Therefore, a microgrid is recommended for its ability to control the dispatch of diesel generation, and its scalability, reliability of supply, and property security. A roof-mounted microgrid can be considered for piloting due to its lower initial investment. The electricity tariff also needs to be subsidized to make it affordable to end-users. Equally, government and community involvement should be prioritized to achieve long-term economic sustainability of the microgrid.
Open Access
Particulate matter versus airborne viruses : distinctive differences between filtering and inactivating air cleaning technologies
(2022) Burdack-Freitag, Andrea; Buschhaus, Michael; Grün, Gunnar; Hofbauer, Wolfgang Karl; Johann, Sabine; Nagele-Renzl, Anna Maria; Schmohl, Andreas; Scherer, Christian Rudolf
The current pandemic of the SARS-CoV-2 virus requires measures to reduce the risk of infection. In addition to the usual hygiene measures, air cleaners are a recommended solution to decrease the viral load in rooms. Suitable technologies range from pure filters to inactivating units, such as cold plasma or UVC irradiation. Such inactivating air cleaners, partly combined with filter technology, are available on the market in various designs, dimensions and technical specifications. Since it is not always clear whether they may produce undesirable by-products, and the suitability for particular applications cannot be assessed on the basis of the principle of operation, the effectivity of six inactivating devices was investigated in a near-real environment. The investigations were based on a standard method published by the VDI. The procedure was extended in such a way that a permanent virus source was simulated, which corresponds to the presence of a person suffering from COVID-19 in a room. The study addresses the difference of the mere presence of viruses to the determination of the virulence. As a result, a deep understanding is provided between the behavior of a virus as a pure aerosolized particle and its real infectivity in order to enable the assessment of suitable air cleaners.
Open Access
Assessing land use efficiencies and land quality impacts of renewable transportation energy systems for passenger cars using the LANCA method
(2022) Uusitalo, Ville; Horn, Rafael; Maier, Stephanie D.
Targets to reduce global warming impacts of the transportation sector may lead to increased land use and negative land quality changes. The aim of this paper is to implement the Land Use Indicator Calculation in Life Cycle Assessment (LANCA®) model to assess land quality impacts and land use efficiencies (concerning occupation and transformation) of different example renewable transport energy systems for passenger cars. In addition, the land use impacts are normalized according to the Soil Quality Index building on LANCA® and included in the environmental footprint. The assessment is based on information from GaBi life cycle assessment software databases and on literature. Functional unit of the model is to provide annual drive of 18,600 km for a passenger car in the EU. The analysis includes examples of biomass, electricity, electricity to fuels and fossil-based energy systems. Our findings confirm previous research that biomass-based transport energy systems have risks to lead to significantly higher land occupation and transformation impacts than do fossil oil or electricity-based ones. According to the LANCA® model, methane from Finnish wood and German corn has the highest impacts on filtration and the physicochemical filtration reduction potential. Sugarcane ethanol and palm oil diesel systems, on the other hand, lead to the highest erosion potential. Electricity-based transportation energy systems appear to be superior to biomass-based ones from the perspectives of land occupation, land transformation, and soil quality impacts for the selected examples. Land quality impacts should be taken into account when developing and expanding renewable transportation energy systems. The paper shows that the LANCA® method is applicable for the assessment of transport systems in order to provide extended information on environmental sustainability, which should be included more often in future analysis. However, it can be challenging to interpret underlaying assumptions, especially when aggregated information is used from databases.

02 Fakultät Bau- und Umweltingenieurwissenschaften

Browse

Filters

Settings

Sort By

Results per page

Search Results