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Was ist synthetisches Gas?
(2019)
The earth as we know it can only continue to exist if humanity finds a way to switch to a sustainable use of energy and resources. This work contributes to the research carried out to achieve this goal by improving the coating of adsorptive materials. These are used in heat transformation and drying processes that allow for efficient temperature and humidity control in buildings. A central component of these adsorptive coatings is the binder that acts as "glue" in the manufacturing of the coating. In this work the methods to evaluate binder performance regarding their thermal stability under the process conditions, their mechanical stability and their influence on the adsorptive properties of the coating were established. The coatings have to meet special requirements due to the thermal stresses and low pressure atmosphere they experience in these applications. A selection of silicone binders was then characterized with the established tests according to these requirements. Additionally a selection of inorganic binders was investigated because they allow for the use of high desorption temperatures and thus a high energy efficiency of the process. Out of these binders Silres® MP50E emerged as the most promising one due to very good adsorptive properties of the coating, its good temperature stability and ease of use. While some of the inorganic binders showed very good adsorptive properties and temperature stability the mechanical stability of all inorganic binders was not sufficient for their use in adsorption heat transformation technology. This is the first time that a broad selection of binders was evaluated with regards to adsorptive coatings and the results published in literature. With a suitable binder identified, the next step was to optimize the coating of the heat exchangers in order to work out how to manufacture the most efficient and powerful heat exchangers. Samples with different coating thicknesses were manufactured in small scale and full scale and their adsorption behavior was characterized. It could be shown for the first time that it is possible to increase energy efficiency by improving the mass ration of adsorber to coating and increase the delivered power at the same time. This was shown for small and full scale samples. It was shown that under the corresponding conditions the heat transfer from the coating layer to the adsorber metal substrate is the limiting step in the process. These results can now be used for the planning and construction of adsorbers. With knowledge of a suitable binder and how to coat efficient, powerful adsorbers, the coating process itself was improved to allow for industrial scale manufacturing. A central point here is the ability to control slurry rheology. Out of many rheology additives those that are suited for the application in adsorption heat transformation were identified and their influence on the slurry rheology thoroughly characterized. Additionally the process of slurry preparation could be simplified for several different adsorbents. Here it was shown that the supersonic deagglomeration step is not necessary to prepare a slurry. Extending the possible coating techniques and in addition to the dip coating process used so far, the spray coating of adsorptive coatings was established for the first time in literature. This process is widely used in the industry and allows for easier plugin into existing coating processes. For the coating of high resolution patterns a proof of concept of the screen printing process was carried out.
Mit "InnovationCity Ruhr - Modellstadt Bottrop" soll ein typisches Stück Ruhrgebiet mit rund 70 000 Einwohnern bis zum Jahr 2020 klimagerecht umgebaut werden. Benjamin Best rekonstruiert den Partizipationsprozess des Projektes, er analysiert seine Begrenzungen und zeigt Weiterentwicklungsmöglichkeiten auf. Die empirische Studie basiert auf qualitativen Methoden der empirischen Sozialforschung, auf teilnehmenden Beobachtungen in der Modellstadt und der Teilnahme an ausgewählten Beteiligungsveranstaltungen. Mittels Interviews mit Expertinnen und Experten identifiziert der Autor kulturelle Faktoren, die die Form der Partizipation im Kontext von InnovationCity sowie den Verlauf des Gesamtprojektes bestimmt haben.
Responsible consumption and production is one of the Sustainable Development Goals of the United Nations. To achieve this goal the currently high extraction rates of natural resources, that our economy is based on, needs a transformation of the consumption and production system considering technological as well as social change. One of the promising transition approaches is seen in collaborative consumption with its many facets of socio-cultural innovations and fast growing number of participants and businesses. With a decreasing production of goods, due to a utilisation of underutilised assets, these offers might support an absolute reduction of the global resource use. However, a positive environmental effect depends on the setting and the social practices of such sharing offers and is not sustainable or resource efficient generally. Also, resource efficient practices with a low diffusion potential that stick in a niche offer no leverage to achieve sustainable consumption patterns. Thus, this paper describes a mixed method approach to analyse the resource efficiency and diffusion potential of 20 sharing offers in the area of mobility, housing & travel and everyday objects in Germany. Results show that the overall positive environmental connotation of sharing offers cannot be confirmed. We identified five clusters of offers that are all treated to be differently when it comes to deploying the positive potential and avoid unnecessary societal effort to achieve the mentioned Sustainable Development Goal.