Entwicklung von anwendungsangepassten akustischen Absorbern unter Nutzung von Simulationstechnik

Innerhalb eines Forschungsprojekts in Kooperation mit der Universität Göttingen wurden im Projekt Abocorn Absorbermaterialien aus nachwachsenden Rohstoffen qualifiziert. Im Rahmen von weiteren Studien werden die Materialien und Modelle weiter angepasst, um eine bestmögliche Konstellation eines akustischen Absorbers herzustellen.Within a research project in cooperation with the University of Göttingen, absorber materials made of renewable raw materials were qualified in the Abocorn project. In the course of further studies, the materials and models will be further adapted to produce the best possible constellation of an acoustic absorber

Mechanical performance evaluation of fiber composites equipped with In-Situ wireless sensor bodies

In modern day structural engineering, fiber-composites play a vital role for their capability for light-weight construction and high stiffness value. More and more applications are being developed in various industries ranging from science, architecture and engineering. These structures can also be equipped with multi-component sensor systems for different performance evaluations both during pre- and post-curing processes. In this work a novel method is developed to place wireless sensors inside the fiber reinforced composite system to enable multifunctionality without much trade-off in mechanical performance. Key objective here was to optimize the sensor shape to minimize stress accumulation and crack propagation around the sensor geometry inside the cured composite sample under stress. A finite element simulation model is developed for this purpose and a parametric model for the sensor geometry provided better insight into the force distribution along the fibers around the sensor element. Consequently, different testing sample combinations were prepared, for which, fibers were either cut or bend around the sensors and dielectric channels. Various composite samples with different shapes of sensor dummies were also experimentally tested to validate the computational results. CT scan models of post-cure samples before and after loading enabled in-depth understanding of fiber alignment that could cause disturbances in overall mechanical performance. The scan models also provided with sufficient information about unwanted porosity, and micro-crack growth inside the composite under loading, which turned out to be vital for establishing a reliable simulation model and improving parameters in manufacturing process. In the end, the goal of the work was to transport the know-how of such production unit from experimental and flexible manufacturing system like vacuum assisted resin infusion (VARI) to more sophisticated processing systems like prepreg manufacturing where all necessary information can be provided as inputs prior to the impregnation, thus removing error occurred due to manual handling

Einfluss der elektrischen und thermischen Speicherkapazität auf die Netzbelastung bei Einfamilienhäusern mit regenerativer Eigenerzeugung, Elektrowärmepumpenheizung und hohem Autarkiegrad

Fokus der Arbeit steht das Energiesystem eines Einfamilienhauses, dessen elektrischer und thermischer Energiebedarf bilanziell zu 100 % aus regenerativen Quellen bereitgestellt wird. Heizwärme- und Trinkwarmwasserbedarf werden mittels einer elektrischen Wärmepumpe gedeckt. In Kombination mit einem Batterie- und einem Wärmespeicher trägt diese dazu bei, die fluktuierend verfügbare erneuerbare Energieerzeugung in das Gebäudeenergiesystem zu integrieren. Übergeordnete Zielstellung der Arbeit ist die Untersuchung des Einflusses elektrischer und thermischer Speicherkapazitäten auf die Belastung des elektrischen Verteilnetzes in wärmepumpenbeheizten Einfamilienhäusern. Daraus werden drei Forschungsfragen abgeleitet, welche (1) auf den Einfluss des EE-Erzeugungsmixes sowie (2) die wechselseitige Beeinflussung der eingesetzten thermischen und elektrischen Speicherkapazitäten abzielen und (3) den Beitrag der nach heutigen Planungsgrundsätzen dimensionierten Speicherkapazitäten zur Netzentlastung untersuchen. Basierend auf den Modellen der einzelnen Systemkomponenten wird ein vereinfachtes Modell des Gebäudeenergiesystems in Form eines Optimierungsproblems (MILP) mit der primären Zielstellung der Minimierung der maximalen Netzbelastung entwickelt. Mit diesem Modell wird, unter der grundlegenden Annahme der bilanziellen Autarkie, eine Vielzahl an Jahressimulationen für verschiedene Kombinationen der eingesetzten elektrischen und thermischen Speicherkapazitäten mit unterschiedlichen Eingangsdaten hinsichtlich der Wetterbedingungen (Temperatur, Globalstrahlung, Windgeschwindigkeit) durchgeführt. Mittels der erhaltenen Ergebnisse erfolgt die Ableitung eines Metamodells zur Beschreibung des funktionalen Zusammenhangs der Abhängigkeit der maximalen Netzbelastung von den eingesetzten Speicherkapazitäten und des Erzeugungsmixes. Das Metamodell wird anschließend in einem nicht-linearen Optimierungsmodell zur Auslegung des Erzeugungsmixes, der maximalen Netzbelastung und der Speicherkapazitäten unter Berücksichtigung der jeweiligen Kosten aus gesamtenergiesystemischer Sicht eingesetzt. Weiterhin wird das Metamodell verwendet, um den Einfluss der eingesetzten Speicherkapazitäten auf die maximale Netzbelastung und den Autarkiegrad im Bereich der heute wirtschaftlichen Speicherdimensionierung des betrachteten Gebäudes zu untersuchen. Als Referenzgebäude wird ein Einfamilienhaus im Niedrigenergiehausstandard mit einem Jahresheizenergiebedarf von 3200 kWh und einem elektrischen Energiebedarf von 5250 kWh betrachtet. Hinsichtlich der Auslegung des Erzeugungsmixes, des Netzanschlusses und der Speicherkapazitäten ergibt sich ein kostenoptimales Verhältnis der installierten Photovoltaik- zu Windleistung von etwa 0,25 zu 1. Dabei kommt aufgrund des Kostenvorteils gegenüber einem elektrischen Speicher ausschließlich ein thermischer Speicher mit einer Kapazität von 57 kWh (etwa 5000 L) zum Einsatz. Die Auswirkungen der eingesetzten Speicherkapazitäten auf die maximale Belastung des elektrischen Verteilnetzes hängt stark vom Erzeugungsmix ab. Während thermische Speicher im Bereich der heute üblichen Auslegung für das oben genannte Referenzgebäude (Batteriespeicher mit 6,56 kWh und thermischer Speicher mit einem Volumen von 570 L) für einen winddominierten Erzeugungsmix den deutlichsten Einfluss auf die Reduktion der maximalen Netzbelastung haben, sind Batteriespeicher für einen photovoltaiklastigen Erzeugungsmix vorzuziehen. Weiterhin zeigen die Ergebnisse, dass in den winddominierten Szenarien durch für den Einfamilienhaussektor technisch durchaus realisierbare Steigerung der eingesetzten Speicherkapazitäten Autarkiegrade um 80 % erreicht werden können. Bei höheren Photovoltaikanteilen sind aufgrund des erhöhten saisonalen Ausgleichsbedarfs zwischen Heizenergiebedarf und EE-Bereitstellung zum Erreichen desselben Autarkiegrades unrealistisch hohe Speicherkapazitäten erforderlich.The focus of this work is the energy system of a single-family house, whose electrical and thermal energy demand is provided by renewable sources at 100 %. Heating and domestic hot water requirements are covered by an electric heat pump. In combination with a battery and a heat storage system, this helps to integrate the fluctuating renewable energy generation into the building energy system. The overall objective of this work is to investigate the influence of electrical and thermal storage capacities on the load of the electrical distribution network in heat pump heated single family homes. Three research questions are derived from this, which (1) focus on the influence of the RE generation mix and (2) the mutual influence of the thermal and electrical storage capacities used, and (3) investigate the contribution of storage capacities sized according to current planning principles to grid load relief. Based on the models of the individual system components, a simplified model of the building energy system is developed in the form of an optimization problem (MILP) with the primary objective of minimizing the maximum grid load. With this model, under the basic assumption of a 100 % self-sufficiency, a large number of simulations, covering a timeframe of one year, are performed for different combinations of the applied electrical and thermal storage capacities with different input data regarding weather conditions (temperature, global radiation, wind speed). By means of the obtained results, a metamodel is derived to describe the functional relationship of the dependence of the maximum grid load on the deployed storage capacities and the generation mix. The metamodel is then used in a non-linear optimization model to design the generation mix, the maximum grid load and the storage capacities, taking into account the respective costs from an overall energy system perspective. Furthermore, the metamodel is used to investigate the influence of the applied storage capacities on the maximum grid load and the degree of self-sufficiency in the range of today’s economic storage dimensioning of the considered building. A single-family house in low-energy standard with an annual heating energy demand of 3200 kWh and an electrical energy demand of 5250 kWh is considered as the reference building. With respect to the design of the generation mix, grid connection, and storage capacities, the cost-optimal ratio of installed photovoltaic to wind power is about 0.25 to 1, using only thermal storage with a capacity of 57 kWh (about 5000 L) due to the cost advantage over electrical storage. The impact of the storage capacities used on the maximum load on the electric distribution system is highly dependent on the generation mix. While thermal storage in the range of the current design for the above reference building (battery storage with 6,56 kWh and thermal storage with a volume of 570 L) for a wind-dominated generation mix has the most significant impact on reducing the maximum grid load, battery storage for a photovoltaic-heavy generation mix is preferable. Furthermore, the results show that in the wind-dominated scenarios, increases in the storage capacities self-sufficiency levels around 80 % can be achieved. At higher photovoltaic fractions, unrealistically high storage capacities are required to achieve the same degree of self-sufficiency due to the increased seasonal balancing needs between heating energy demand and RE supply

Establishment of a research focus on resilient sustainable climate neutral agricultural production: resilient farming initiative

Efficient and sustainable agricultural production is a pivotal factor in meeting the nutritional needs of an expanding global population. However, it is imperative to optimize national, regional and local effectiveness to support government initiatives towards climate neutrality and resilience, while simultaneously ensuring economic viability for farmers. A significant reduction in the cost of goods must be accompanied by a decrease in their global warming potential contribution to maintain competitiveness in the world market. As such, it is necessary to adopt practices that enhance productivity while minimizing environmental impacts. This paper discusses potential solutions for the sustainable enlargement of botanical product portfolios towards essential oil products and natural extracts for value-added products, such as natural pharmaceuticals, cosmetics, agrochemicals and materials by direct waste valorization. Contributions from the fields of automation and digitalization provide the basic technology for the realization of the approaches presented. Agricultural photovoltaics can contribute to the goal of the reduction of the cost of goods and global warming potential, such as the already established utilization of biogas. The potential of the research initiative described is demonstrated by basic data on key characteristic numbers and costs from the literature. The economic potential for climate neutrality and the reduction of global warming potential contribution is seen in magnitudes of factors 5–10. A research initiative is recommended and exemplified for the industrialization of such integrated processing

Bestimmung von Anwendungsreibwerten stirnseitig befestigter Freiläufe

Für eine sichere Auslegung der Mehrschraubenverbindung zwischen Freilaufaußenring und angrenzendem Flansch ist eine möglichst genaue Kenntnis des Reibwertes in der Trennfuge erforderlich. Dieser Artikel gibt einen Überblick über die Ermittlung von Anwendungsreibwerten an Flachproben, welche eine ähnliche Oberflächentopographie aufweisen wie der Freilaufaußenring. Untersucht wird der Einfluss von verschiedenen Betriebsstoffen, Oberflächenzuständen und Schmiermitteln. Zudem wird eine Aussage bezüglich der Übertragbarkeit der Ergebnisse auf die Einbausituation getroffen.For a reliable dimensioning of the multi-bolt connection between the freewheel outer ring and the adjacent flange, it is necessary to know the coefficient of friction in the contact zone as accurately as possible. This article provides an overview of the determination of friction coefficients on flat specimens with a surface topography similar to that of the freewheel outer ring. The influence of different surface conditions and lubricants is investigated. In addition, a statement is made regarding the transferability of the results to the installation circumstances

Einfluss der Schmierung auf die Gestaltfestigkeit der Passverzahnung

Die Dimensionierung von Passverzahnungen muss verschiedene Aspekte berücksichtigen. Dazu gehören neben der Gestaltfestigkeit auch die Verschleißfestigkeit und die dazwischen agierende Reibdauerschädigung. Mit diesem Betrag wird für die Wahl eines geeigneten Festigkeitsnachweises Licht in den Bereich zwischen Gestaltfestigkeit und Reibdauerschädigung gebracht und der Einfluss der Reibbeanspruchung im Kontakt auf die Beanspruchung in der Zahnfußausrundung geklärt.The dimensioning of splined shaft-hub connections takes account of fatigue strength and wear plus the blended fretting load. Within this paper a detailed view is given on friction and their impact on fatigue strength in the foot root

Particle fouling at hot reactor walls monitored In situ with a QCM-D and modeled with the frequency-domain lattice Boltzmann method

Fouling at a hot reactor wall during emulsion polymerization was studied in-situ with a quartz crystal microbalance with dissipation monitoring (QCM-D). Transient maxima in resonance bandwidth were observed, which are typically interpreted as the signature of a coupled resonance. However, the most common type of coupled resonances, the film resonance, cannot explain these observations, because the film resonance should occur first on the high overtones (on the overtones with small wavelength). In experiment, the low overtones reach the maximum first. The maximum in dissipation can be explained with the particulate nature of the sample. As the particles flatten out and merge, the height of the layer decreases and the surface becomes smoother. The decreasing height lets the layer go through the film resonance in reversed order. Also, the decreasing roughness lets the bandwidth decrease, unrelated to the film resonance. The argument is substantiated with a simulation based on the frequency-domain lattice Boltzmann method (FD-LBM). Apart from explaining the features seen in QCM experiments on particle fowling, this case study demonstrates the capabilities of FD-LBM

The structure of the ionic liquid / electrode interface and its possible influence on electrochemical materials synthesis: an in situ STM and AFM Study

Ionic liquids (ILs) have become one of the most popular material classes over the past twenty years. They have been considered as alternative materials to molecular solvents and molten salts in various applications (e.g. batteries, capacitors, lubricants, solvents for electrodeposition purposes). A detailed understanding of the IL/solid interfacial nanostructure and of the spatial distribution of the electroactive species at the interface is important for the development of various technical processes using ILs. In the present work the structure of the electrified IL/solid interface was investigated using in situ scanning tunnelling microscopy (STM) and atomic force microscopy (AFM). Various ILs, namely [Py1,4]TFSA, [Py1,4]FAP, [Py1,4]FSA, [Py1,4]TfO, [EMIm]TFSA, [OMIm]TFSA, [EMIm]FAP, [EMIm]TfO and [HMIm]FAP were applied for this study. In situ AFM reveals that multiple interfacial layers are present at the IL/electrode interface. Furthermore, the applied potential determines whether cations or anions are preferably adsorbed to the substrate with stronger near surface layering detected at higher positive or negative surface potentials. Both the cation and the anion of the IL have a strong influence on the structure and composition of the interface. In situ STM shows that the appearance of the Au(111) and H-terminated p-Si(111) surfaces is different in various ILs, due to specific ion/surface and ion/ion interactions, which are dependent on the type of the functional groups (pyrrolidinium or imidazolium ring and the length of the alkyl chains), resulting in a different interfacial structure for various cations. With the same anion, the Au(111) surface undergoes the (22 x √3) reconstruction with [Py1,4]+ during cathodic polarization, but with [EMIm]+, [HMIm]+ and [OMIm]+ the herringbone superstructure has not been obtained. Furthermore, different [OMIm]TFSA superstructures with the lateral size between 1.2 and 1.7 nm are probed with in situ STM on highly ordered pyrolytic graphite (HOPG) at high negative electrode potentials, as a result of several cation and/or anion layers probed at the same time by the STM tip. AFM measurements show that the imidazolium cation is adsorbed at the H-Si(111)/[EMIm]TFSA interface leading to an ordered clustered facet structure of ~3.8 nm in size. In comparison, the Si(111)/[Py1,4]TFSA interface appears the same as the native surface under argon. The interfacial structure is sensitive to metal and semiconductor salts dissolved in the IL. In general the ion layering at the IL/solid interface is markedly different in the presence of dissolved solutes than for the pure IL systems, as the presence of salt ions alters both the IL-surface and IL-IL interactions at the interface. For instance, AFM measurements reveal that interfacial layering is markedly weaker in the presence of LiCl and SiCl4 in [Py1,4]FAP. The presence of Li+ and Si(IV) affects interactions between [Py1,4]+ and the gold surface hindering the (22 x √3) Au(111) reconstruction. Marked changes in the IL/Si(111) interfacial structure are obtained on addition of LiTFSA in [Py1,4]TFSA and [EMIm]TFSA. The concentration of the solute has also a significant effect on the structure of the IL/electrode interface. Thus, considerable changes are obtained on addition of high concentrations of NaFSA and LiTFSA in [Py1,4]FSA and [Py1,4]TFSA, respectively. For the [EMIm]TfO/Au(111) interface the structure of the innermost layer also depends on the amount of added water. A transition from a multilayered structure to a classical double layer structure occurs at -1.0 V vs. Pt on changing the water concentration from 30 to 50 vol%. The formation of a double layer structure at the IL/Au(111) interface is also obtained on increasing the concentration of SiCl4 in [Py1,4]FAP. In situ AFM force-separation measurements confirm that the dissolved solute is present within the innermost (Stern) layer. The altered interfacial structures represent the best compromise between the IL ion and solute surface affinities, packing constraints, and charge localisations. Thus, the IL EDL is highly complex both in the pure ILs and in the presence of solutes and often leads to an unpredictable electrochemical behaviour. This in turn should affect the reactions that occur at the IL/electrode interface (e.g. metal deposition). Thus, in [Py1,4]TFSA, TaF5 can be reduced to elemental Ta, while in [Py1,4]FAP the electroreduction processes are practically inhibited. The difference for Si deposition from SiCl4 in [Py1,4]TFSA and [Py1,4]FAP is roughly 1 V. The crystal sizes of the electrodeposited Ga varies upon changing the ILs. The deposit made from [Py1,4]TFSA consists of spherical structures of 60-260 nm in diameter, while the crystal sizes of a Ga deposit obtained from [Py1,4]TfO are between 15 and 110 nm. In the case of [Py1,4]FSA a nanocrystalline Ga deposit with a crystal size of less than 50 nm is obtained. Furthermore, GaSb obtained in [EMIm]TFSA and [Py1,4]TFSA exhibits a band gap of about 1.2 eV and 0.9 eV, respectively. The present work shows that the electrodeposition of metals and semiconductors in ILs is complicated. On the one hand, the (chemical) structure of the IL has an influence on the EDL structure of the Au(111)/IL interface. On the other hand, the addition of precursors, which are required for the deposition processes, can also affect the structure of the electrode/IL interface. Furthermore, the nanostructure of interfacial layers can vary if the concentration of the precursor is increased, which might facilitate the deposition processes. Such interfacial effects have to be considered for all applications that involve reactions at the IL/solid interface

Eine experimentalökonomische Untersuchung von Recyclingverhalten

Natürliche Ressourcen stellen einen bedeutenden Inputfaktor in Produktionsprozessen dar und tragen zum menschlichen Wohlstand bei. Sie sind jedoch nur begrenzt verfügbar. Dies gefährdet zukünftiges Wachstum und birgt Konfliktpotential. Zudem werden natürliche Ressourcen durch negative Umweltauswirkungen entlang der Wertschöpfungskette beeinträchtigt und dienen etwa als Senke für klimaschädliche Treibhausgasemissionen oder Abfälle. Somit zieht die Ressourcenknappheit vielfältige lokale wie globale Probleme nach sich, denen im Hinblick auf Nachhaltigkeitsziele durch den Aufbau einer Kreislaufwirtschaft entgegengewirkt werden kann. Die Transformation der Wirtschaft erfordert neben der Schaffung geeigneter politischer Rahmenbedingungen und erheblicher technologischer Investitionen insbesondere auch die Mitwirkung von Privathaushalten, damit Abfälle recycelt und die darin enthaltenen Rohstoffe im Kreislauf gehalten werden können. Aus ökonomischer Perspektive besteht diesbezüglich ein Dilemma, da private Kosten des Recyclings den unmittelbar daraus resultierenden privaten Nutzen übersteigen: Während rational nutzenmaximierende Akteure entsprechend der Standardtheorie auf jegliche Recyclingaktivität verzichten, könnten sie bei Kooperation wechselseitig vom nicht-ausschließbaren Nutzen des Recyclings profitieren und sich insgesamt besserstellen. Die Ökonomik bietet zwar mit Instrumenten wie dem Pfandsystem Lösungen an – diese unterliegen jedoch Grenzen und lassen sich praktisch nicht zur Regulierung aller relevanten Bereiche einsetzen. In dieser Arbeit wird die freiwillige Mitwirkung am Recycling in unterschiedlichen institutionellen Settings experimentalökonomisch im Labor untersucht. Grundlage bildet ein erweitertes Öffentliches-Gut-Spiel, in dem Recycling als Investition in ein Öffentliches Gut Umwelt- und Ressourcenschutz interpretiert wird. Konkret wird die Gesellschaft in zwei gleichgroße Klubs unterteilt. Die Gesellschaftsmitglieder erhalten dann die Möglichkeit zur Investition in ein gesamtgesellschaftlich nutzenstiftendes Öffentliches Gut sowie in ihr Klubgut: Der hier erzielte Nutzen kommt exklusiv den Klubmitgliedern zugute. Vor diesem Hintergrund bezieht sich die Fragestellung dieser Arbeit auf die Bedeutung der Einführung exklusiver Recyclingsysteme, ihre Zusammensetzung sowie die Wirkung eines Wettbewerbs zwischen ihnen. Die Ergebnisse zeigen, dass die Neueinführung der Klubgüter im Laufe des Experiments zu höheren Beiträgen in die Klubgüter und schließlich zu höheren Gesamtbeiträgen führt. Hinsichtlich der Klubeinteilung wird zwischen zufälliger Einteilung und der Einteilung in Klubs mit hoher, respektive niedriger Umwelteinstellung unterschieden. Die einstellungsbezogene Klubeinteilung führt zu höheren Beiträgen zum Öffentlichen Gut sowie zu höheren Gesamtbeiträgen. Auf Klubebene leisten die Mitglieder der Klubs mit höherer Umwelteinstellung höhere Gesamtbeiträge. Die wettbewerbliche Komponente besteht darin, dass in jeder Gesellschaft der Klub, in den innerhalb eines bestimmten Zeitraums weniger investiert wurde, vorzeitig aufgelöst wird. Die betroffenen Mitglieder können fortan nur noch in das Öffentliche Gut investieren. Bei zufälliger Klubeinteilung lässt sich diesbezüglich kein signifikanter Unterschied feststellen. Allerdings wirkt sich der Wettbewerb in Kombination mit einstellungsbezogener Gruppeneinteilung tendenziell kontraproduktiv auf die Gesamtbeiträge aus. Dies ist zuvorderst darauf zurückzuführen, dass die Mitglieder der Klubs mit niedriger Umwelteinstellung signifikant weniger zum Klubgut beitragen als ohne Wettbewerb. Zusammengenommen lassen die Ergebnisse darauf schließen, dass die Einführung zusätzlicher Recyclingoptionen mit spürbarem Nutzen sowie die Verschiebung von Recyclingentscheidungen in den Kontext sozial verbundener Gruppen mit nicht-diskriminierender Identität zu höherer Beteiligung am Recycling führen.Natural resources play a crucial role in production processes and contribute to human prosperity However, these resources are limited. This poses a threat to the future growth and may cause conflicts in the long run. Additionally, the usage of natural resources has a negative impact on the environment at almost every step along the value chain. For instance, natural resources act as sinks for greenhouse gas emissions or waste. Summed up, resource scarcity leads to various local and global issues that can be resolved by developing a circular economy. Apart from creating adequate policy frameworks and making substantial technological investments, it is crucial to have households involved in the economic transformation: By recycling their waste, they retain the raw materials in the cycle. In economic terms, this poses a dilemma, as the costs of recycling incurred by private households exceed the direct benefits derived from it. Although standard economic theory suggests that rational and utility-maximizing agents should refrain from recycling, they could benefit from the non-excludable advantages of recycling and improve their overall outcome if they cooperate. While the economic instruments such as deposit systems could offer potential solutions, its versatility is limited and cannot be applied to regulate all relevant areas in practice. This work investigates the voluntary participation in recycling in different institutional settings by using experimental methods in the laboratory. The research is based on an extended Public Goods Game where recycling is interpreted as an investment in the environment and resource protection. Specifically, the population is divided into two equal-sized clubs. All members of the population are then given the opportunity to invest in either a Public Good that benefits the society as a whole, or in their own club where the achieved benefit is exclusively for club members. Against this background, this work's focus is on the significance of exclusive recycling systems, their composition, and the effects of competition between them. The results indicate that the introduction of club goods during the experiment leads to higher contributions towards them and results in higher total contributions. Regarding club division, a distinction is made between random division and division into clubs with their members having high versus low environmental attitudes. The club division based on attitude leads to higher contributions to the Public Good as well as higher total contributions. At the club level, members of clubs with relatively high environmental attitudes show higher total contributions. The competitive component is that within each society, the club where less has been invested within a certain period gets dissolved earlier. From that point on, the involved members are only permitted to invest in the Public Good. Random club assignments did not result in any substantial contrast. Nevertheless, scheduling competitions along with attitudinal grouping leads to an negative influence on the overall contributions. This mainly results from the reduced contribution of members from clubs with low environmental attitudes to the club's benefit as compared to those without competition. Collectively, the findings imply that the introduction of more recycling options with tangible benefits leads to higher recycling participation – as well as shifting recycling decisions to socially connected groups with non-discriminatory identities