The goal of this thesis was to provide designers guidance in designing their yet-to-be designed products that contain injection moulded parts in a way that allows for interchangeable, functionally equivalent spare parts produced with additive manufacturing in the future. The project was scoped to stereolithography as the additive manufacturing technology, focusing on geometrical and mechanical aspects of product design. The result of the thesis is a newly developed guide, referred to as the ‘form factor optimisation guide’. This guide was developed by analysing literature and conducting various case studies.

Two newly developed approaches are part of the form factor optimisation guide, referred to as the ‘geometry-based part coupling approach' and the ‘form factor definition approach’. A designer can compose a product architecture map using the geometry-based part coupling approach to map the relationships of coupled parts. Parts are considered coupled when they influence each other’s geometry. The product architecture map, along with the list of requirements, is used to define the ‘form factor’ of a part. This form factor is the design space and non-design space for the part's geometry. Using the form factor, the designer can optimise the part for production with injection moulding and stereolithography. It may occur that the form factor does not allow the designer to cope with the limitations of each manufacturing technology. In this case, ‘reciprocity’ is applied. Reciprocity is the term that is used to describe the process of going back and forth between the designs of coupled parts and their requirements. Reciprocity is applied until the form factor allows for interchangeable, functionally equivalent parts produced with injection moulding and stereolithography.

Noise pollution is a growing concern in homes and workplaces, making acoustic solutions more important than ever. This project explores the potential of corn cobs (an agricultural by-product) to create sustainable acoustic panels. The goal is to offer an alternative to conventional soundproofing materials that is both eco-friendly and practical for real-world use.

Traditional acoustic panels are often made from synthetic materials like mineral wool, foam, or fiberglass. While effective, these materials come with environmental downsides, including high carbon footprints, waste generation, and, in some cases, the release of volatile organic compounds (VOCs) that can affect indoor air quality. This project takes a different approach by repurposing agricultural waste into a functional and circular product.

To test the concept, a prototype panel was developed. It measures 260 cm long, 30 cm wide, and 3 cm thick, designed to fit into U-profiles that attach to a floor-to-ceiling frame. The sound absorption coefficient was measured at approximately 0.35, meaning it provides some noise reduction but still has room for improvement. Mechanical tests revealed that the panel’s bending and tensile strength are lower than standard requirements, highlighting the need for a stronger or more suitable binder.

Despite these technical challenges, the project has promising advantages. Corn cobs are widely available and inexpensive, making them a cost-effective raw material. The panels support a strong sustainability narrative, helping brands improve their eco-friendly positioning. They also do not emit VOCs, making them safer for indoor use. Aesthetically, they have a neutral, modern appearance that can suit various interior styles, and their customizability allows for different design possibilities.

However, there are still some limitations. The natural inconsistencies of the material, along with its sensitivity to moisture, could affect long-term durability. Some users might also question its strength, especially compared to established alternatives. The texture of the panels may not appeal to everyone, and while the production process is scalable using hydraulic pressing, setting up large-scale manufacturing could be costlier than expected. Additionally, competing with well-known brands will require strong market positioning.

To make the product commercially viable, key aspects such as cost, regulations, and consumer demand need further evaluation. The main target audience includes first-time homebuyers and renovators who prioritize sustainability, but the panels could also be applied in commercial spaces. The next steps will focus on improving strength and moisture resistance while maintaining environmental benefits.

This project demonstrates how agricultural waste can be transformed into useful, sustainable materials. While further refinements are needed, corn cob acoustic panels have the potential to become a real alternative to conventional options. By balancing sustainability, function, and design, they could contribute to a more circular and environmentally responsible construction industry.

This thesis presents the design process of a novel noise barrier design made from horizontally arranged, decommissioned wind turbine blade material.

To address climate change challenges worldwide, wind power is increasingly being adopted. The wind turbine blades (WTBs) used for them are decommissioned after 20-25 years, at which point a problem emerges: the complex material composition makes that current end-of-life options result in the loss of material value without regaining significant economic value. The aim is therefore to structurally reuse WTB material in applications that preserve material integrity and prolong its lifetime. Scalable and long-lasting noise barriers are consequently identified as a fitting opportunity. This thesis focuses on horizontal arrangements of WTB material for use in a noise barrier as this is underexplored and will more closely resemble conventional building materials.

However, due to the variable curved shapes of WTBs, seamless assembly in noise barriers becomes challenging. Especially since gaps compromise the noise attenuation of a noise barrier. The proposed design is a solution to that challenge. It configures WTB panels in modular cassette-panel-cassette sections that allow for tackling alignment issues and can be easily (dis)assembled on frame structures. It attenuates noise by reflecting sound waves into the sky off of tilted, continuous front panels. A second column of panels further reduces sound transmission behind the barrier. Continuity and aesthetic harmony of the barrier in its surroundings is aimed for by use of climbing plants and a green colour palette.

The design follows from a process based on research. Led by a vision on durability, modularity and feasibility, ideas are developed into two concepts that are evaluated with input from experts. Subsequently, one integrated concept is further developed through (CAD) modelling, prototyping, testing, simulating, and a survey.

Three research questions are answered throughout this process. To ensure seamless fitting, a parametric model is developed to inform segmentation strategies. It filters out excessively curving parts to retrieve suitable panels. Alternating the orientation of cladded panels and avoiding seams in the road-side surface of the assembly further tackle alignment issues. Analysis of existing noise barriers reveals that mounting and assembly are facilitated by use of modular cassette-based systems. Cassettes can accommodate the WTB panels that contain variable curvature. A prototype is developed to test fastening options, resulting in an adjustable and reversible clamp design that allows for acoustic sealing. The resulting cassette-panel-cassette modules can be pre-fabricated off-location to reduce time spent on-location. Maintaining opportunities for next material lifecycles is found to largely depend on resizing activities. Large panels are prioritized as they can be more broadly reused than smaller ones. Additionally, protecting exposed core materials of sandwich structures (balsa wood and foam) against weathering is important. An explorative test with epoxy coatings provides starting insights to this end.

Overall, the valuable insights in this thesis culminate in a functional, feasible and desirable noise barrier made of WTB material, and highlights areas for further industry research.

This graduation project focuses on enhancing the sustainability of the Laerdal suction canister by developing a new reusable canister design for the LCSU, with a design emphasis on personal use. The design report comprises eight chapters, detailing the design research, iteration, and final proposed design.

This thesis investigates how electronic products can be designed for effective recycling, which can reduce the demand for critical raw materials and mitigate environmental and human health risks through the safe removal of hazardous substances. In collaboration with an electronics recycling facility, this study provides practical insights into e-waste recycling through a shredding experiment. By conducting a shredding experiment with four brands of smart TVs the influence of product and part characteristics on the liberation and separation of materials are studied. The insights of this experiment, with a specific focus on connections and materials, are incorporated into Design for Recycling (DfR) guidelines and introduces a novel method to assess the tensions between repairability and recyclability, called: Recyclability Maps.

Key findings include the identification of connections that influence the separation of materials, such as the high liberation degree of snap-fits and the complex behaviour of screws and adhesives. This study demonstrates the critical role of product design in enhancing the recyclability of products and reducing its environmental impact. The developed DfR guidelines offer practical guidance for designers, integrating theoretical insights with empirical data from the recycling experiment. The Recyclability Map method provides a structured approach to evaluate how design choices affect the repairability and recyclability of a product. With this method the smart TVs were analysed on the tensions between these two circular design strategies.

The thesis concludes that effective integration of circular design strategies requires careful selection of connections and materials during the design phase, emphasizing the importance of informed design decisions to promote sustainability.

This graduation project presented the development of a new Photovoltaic-Thermal panel (PVT) module design, aimed at addressing sustainability challenges in conventional solar panels. The research focused on improving repairability and recyclability by replacing the standard ethylene-vinyl acetate (EVA) laminate with a liquid encapsulant. This transformation enhanced the module's thermal stability and light transmittance and innovatively converted the panel into a pioneering photovoltaic-thermal (PVT) system. Experimental prototypes, conducted at the Photovoltaic Materials and Devices - TU Delft, demonstrated the feasibility of this concept. The outcome of this graduation project, conducted for Biosphere Solar, laid a robust foundation for future developments in sustainable solar energy solutions.

The study discusses the challenges posed by substances of concern (SoCs) in products, emphasizing the need to address them within the framework of a circular economy (CE). It introduces the Safe and Circular Design (SCD) method as a potential solution but notes its lack of practical testing. The study focuses on implementing the SCD method in addressing indium tin oxide (ITO) within a liquid crystal display (LCD) monitor, highlighting difficulties due to limited data on SoCs and strategies for their management. An ex-ante life cycle assessment (LCA) compares ITO and an alternative, revealing environmental impacts and challenges in evaluating toxic trade-offs. The application of the SCD method to the LCD case identifies insights and challenges, emphasizing the importance of data availability and multidisciplinary collaboration for safer and sustainable product development. The study recommends refining the SCD method and conducting further case studies to assess its effectiveness across different scenarios. It underscores the need for enhanced data transparency and collaboration among stakeholders to advance safe and sustainable product design.

Plastics have become indispensable in modern life due to their versatility and affordability. However, their widespread use has resulted in far-reaching environmental damage, including the accumulation of plastic waste, fossil fuel depletion, and significant greenhouse gas emissions. Bio-based plastics have been proposed as a sustainable, circular solution to the environmental issues associated with plastics. However, bio-based plastics are not implicitly sustainable or circular. These aspects are influenced by how a plastic is produced and how it is recovered at end-of-life, implying that careful attention needs to be paid to material development and product design. This thesis explores the sustainability and circularity of bio-based plastics by looking at: how they are perceived by value chain actors, potential recovery pathways in a circular economy, and environmental impact.


Although bio-based plastics have the potential to be sustainable, the emissions associated with producing them depend heavily on the biomass sourcing. At the same time, bio-based plastics are not de-facto biodegradable and thus efficient recovery at end-of-life needs to be guaranteed. Circular product design with bio-based plastics requires careful consideration of biomass sourcing and recovery. Although much information regarding these aspects is still missing, the research presented in this dissertation provides some guidelines for circular product design with bio-based plastics. In order to reduce environmental impacts, bio-based plastics should be produced with agricultural by-products or with biomass types with a high conversion efficiency. Biomass for bio-based plastics should be cultivated with minimal use of land, water, chemicals and fossil fuels. Environmental impacts can be reduced further by using renewable energy in the production process. Product designers should also consider what recovery pathway they want to target at end-of-life of a product. The plastic composition and product architecture need to reflect the targeted recovery pathway.@en

Thermoplastic composite materials are increasingly used in aircraft construction due to their high-mechanical properties, toughness, rapid processing rates and reprocessing possibilities at their end-of-life. In the production thermoplastic composite parts, 10-40% of the material remains unused, so-called production waste. Despite being a high-performance material that can be re-processed, real-world applications of the material into structures or products are lacking. This research explores how the thermoplastic composite production waste material can be utilised by designers and engineers, by demonstrating its use in a design process of new applications. This exploration resulted in the design of a structural member, that can be tailored to a specific function, and a design of a pedestrian bridge, which aims to stimulate the creative use of the material. By evaluating the design process, a framework is proposed which engineers and designers can utilise to design new applications from composite waste material.

Electrical and electronic devices are a significant focus in resource sustainability due to increasing demand, resource usage, and waste challenges. Among these, consumer electronics are known for rapid innovation, short product life cycles, and being a part of an industry with many players, making them ideal for applying circularity principles to promote sustainability. However, adopting circular practices requires systemic change and collaboration from diverse stakeholders, necessitating a value chain perspective. Resources for collaborative efforts in the consumer electronics industry, adopting a value chain and circular economy perspective, are limited. Thus, there's a need for new tools and methods to aid organizations in establishing circular value chains through collaboration.

The main goal of this project is to help organizations in the Dutch consumer electronics industry set up an aligned value chain based on Circular Economy principles.A literature review first explored the current state of circular economy adoption, alignment dimensions, and barriers/drivers in the industry. The literature revealed that alignment dimensions are linked to specific barrier/driver categories, that at the same time are linked to the organizational boundaries. Then, semi-structured interviews with representatives from the context were conducted. The relevance of organizational roles within value chains, circular economy and environmental impact awareness, and context-specific drivers and barriers, emerged from them. Collaboration emerged as crucial, necessitating shared responsibility, the use of success stories to attract partners, and clear partner selection criteria.

These insights informed the development of the Circular Value Chain (CVC) method, designed to assist Original Equipment Manufacturers (OEM) in establishing circular value chains for consumer electronic products. CVC is a seven-step iterative process that considers design organizations and OEMs as initiators of the value chain. It begins with a self-evaluation, followed by drafting an initial Product-Service System proposition, to then envision an ideal circular value chain. It is then followed by assessing and selecting suitable partners, and aligning them for an effective collaboration. Various tools were designed and incorporated in the method in the form of circular value chain archetypes, an assessment card and spider diagram, and a table of selection guidelines.Overall, CVC adopts an organizational approach, involving different teams guided by an expert strategic designer.

This project holds practical and academic significance by providing insights into aligning partners within circular collaborations using a value chain perspective and offering a theoretical framework for future research. The designed method and tools bridge existing research implementing a value chain perspective, enhancing their industry applicability and the relevance from a circularity perspective. The included tools focus on assessing partners based on organizational roles and facilitates informed decision-making. Collaboration within value chains is vital for advancing the circular economy, and the CVC method supports this through a value chain perspective, role definition, and selection of the ‘right people’. While testing shows high potential, further refinement is needed for practicality and information inclusion. In sum, the design outcome offers an initial version of a method that should be further explored and iterated on.

This graduation project (Hyfen) elucidates opportunities for mycelium-based innovations in circular aircraft cabin design with a focus on material properties, applications and comparative environmental impacts.
Aircraft cabin interior elements account for 10% of an aircraft’s empty weight, and are replaced 4-5 times during the lifetime of an airframe. Thus, cabin elements are responsible for a significant portion of an airliner’s environmental impacts due to operational emissions and improper waste handling. An understanding of the need to apply circular principles to the cabin led to
heightened interest in mycelium-based materials which are lightweight and biodegradable.

The design goals were 1) Understanding the material properties of mycelium-based materials based on aircraft cabin requirements 2) Identifying optimal applications of mycelium-based materials in an aircraft cabin and developing selected demonstrators & detailed designs 3) Assessing the circularity and comparative Life Cycle Impacts of selected applications.

These goals were achieved through an adaptation of the Material Driven Design methodology. The outcomes of this project included conceptual design and demonstrators of two applications. First, is an optimized bionic partition with mycelium acoustic panels and filler material, weighing 40% less (41,6 kg) than a conventional nomex honeycomb-based composite partition (67 kg). The second is a modular packaging cum meal tray for airlines, aiming to reduce single-use plastic waste.
These specific applications were detailed to highlight the temporal & versatile properties such as competitive insulation (acoustic & impact), damage-resistant textures, foam-like compressive properties, mouldability into complex shapes and comfortable tactile interactions for passengers. They also have a high potential to mitigate the environmental impacts of an aircraft cabin due to weight savings in the bulky interior panels, as demonstrated by a final circularity and fast-track life cycle assessment.
Takeaways from this thesis also include insights into the optimal application families, including hot & cool cases, galley, business class & first class seat shelving systems, cushions and upholstery for seats and even decorative filler material for armrests and accessories. These applications to different degrees, leverage the unique material properties (e.g. low weight, mouldability, apparent sustainable advantage, warm & comforting textures etc.) of pure mycelium and
myco-composite materials. It also adds to an understanding of the design requirements for circular applications using mycelium derivatives and aims to inspire further research & development for deployment.

This thesis provided conclusive foundational qualitative evidence on the potential environmental advantage of mycelium applications over plastics, composites and other petroleum-derived materials in an aircraft cabin. Future recommendations include looking into standardization, commercialization, usability and acceptance. Project Hyfen aimed to be visionary and embolden the stringent aerospace sector to seek solutions in nature for its circularity transition - with biobased materials like mycelium being the building blocks, literally and figuratively

More and more wind turbines are erecting in the landscape, stemming from the need for sustainable energy. However, less attention is paid to the secondary effects of these wind turbines, more specifically, the wind turbine blades. Wind turbine blades are made of composite material, a material that provides many advantageous properties for the desired functionality. Nevertheless, the material is difficult to reuse or recycle after the lifespan of the wind turbine blade. This challenge is expected to result in thousands of tons of decommissioned blades entering the market in the coming years which, due to the absence of good alternatives, are most likely to be disposed of in an unsustainable manner.

This project focuses on how composite material from decommissioned wind turbine blades can be reused in order to retain the value embedded in the material. It explores how delamination can potentially add to design freedom of the material for it to be used in a scalable way and match the large influx of the material. Focus is put on the curved elements of the blade: the inboard and outboard sections. Aside from producing scientific knowledge on the topic, the aim is to exhibit the findings through means of a demonstrator of a potential reuse application.

In chapter one, the thesis starts with research into background information, identifying the knowledge gap, setting the scope and conceiving the mission and research questions for the project. Then, in chapter two, a better understanding of a wind turbine blade is formed based on a reference blade. After this the geometry of the blade parts in focus, together with the material composition is researched. Chapter three dives into the possibilities of retrieving elements out of wind turbine blades and looks at the characteristics of these elements.

In chapter four the delamination of the sandwich structured wind turbine material is explored. It is investigated how this can be done and what potentially influences this process. Then, in chapter five the material characteristics of the retrieved and delaminated elements are analysed. This showed that the material can be elastically deformed, opening up the floor for a broader range of reuse applications.

The most suitable reuse application is then methodically determined in chapter 6. Based on, amongst other things, the material qualities and the vision, the choice fell on a bus shelter. A concept of this is then proposed and concretised in the form of a demonstrator. It exhibits the possibilities of the material and embodies the approach for facilitating reuse of decommissioned wind turbine blades on large scale as presented in the project.

In the end, the report concludes with an evaluation of the design and the process in the form of a discussion, a summary of the findings and multiple recommendations to improve future sustainability with respect to wind turbine blade material

Context
The amount of electronic waste keeps growing, half of which is white goods. In the meantime a transition from gas hobs to induction hobs is taking place. Induction hob have a shorter lifetime and contain more valuable materials. As a consequence, the induction hob e-waste will increase significantly.

To prevent a further increase of e-waste by this growing amount of induction hobs, a circular product is proposed. In this graduation project an induction hob is designed that is fit for the circular economy. Here the focus is on the inner three circles of the Rainbow Model.
For this project the Hood-in-Hob Elevate™ from ATAG Benelux was researched and redesigned.


Research
Research was done into the architecture of the current product, identifying the priority parts and how easily the product can be disassembled. It was concluded that most of the priority parts were located in the induction assembly, which is the part of the product that is hardest to reach. The main reason for it being hard to reach is because the product needs to be taken out of the countertop, which brings multiple complications with it.

Next research into consumer behaviour was done, to gain insight into the product care the consumer performs, the reason of product replacement and the user’s attitude towards refurbished products. It was found that the product was almost never replaced because of technical obsolescence, but because of psychological and functional obsolescence. In order to avoid this type of product replacement, it should be designed for upgradability and remanufacturing. To support this, the product should be easy to disassemble.
It was also found that the only product care the consumer performs is the cleaning of the product. Lastly it was found that the consumer is prepared to buy a refurbished product provided, if the expected lifetime is the same as a new one and if the product is thoroughly cleaned.

Concept
The result of the project is a concept of an induction hob that is fit for a circular economy. The main change compared to the current product is the architecture of the concept.
The induction assembly is changed into two separate modules, which can be disassembled without removing the glass plate from the countertop. The disassembly has been simplified so much, that the consumers are able to replace the induction module by themselves. They can send the module to ATAG for repair, making the repair process faster and using the time of the service engineer more efficient.
Finally, the user interface has been taken out of the product and made into a separate product. The user interface was one of the priority parts which were most difficult to disassemble. By making it separate, it is easier to reach. On top of that the upgradability has been improved this way, there is more upgrade flexibility and no changes to the rest of the product are required.
To conclude the design recommendations are made for detailing the concept even further.

This project set out to design a product that is fit for the circular economy. The outcome is a concept of a product that is easier to disassemble and thus easier to repair, upgrade and remanufacture.

Sitwaking is an adaptive sport derived from wakeboarding, targeting wakeboarders with a physical disability. Although the sport is growing each year, the accessibility level of the sport is low. Investment costs are high and existing products are targeted towards experienced riders.
Relative to wakeboarding, a different setup is required to practice the sport. A sitwaker is seated in a seat, which is attached to a normal wakeboard with an aluminum frame. At the front of the board, a footpad is installed to strap the rider’s feet.
The project has been set up in cooperation with the Willem Hooft Foundation. This is an organisation aimed at improving the accessibility of adapted water sports. It builds forth on a concept design for an adjustable sitkite seat, developed by Marinke Callens. For her project, she did extensive research on the ergonomic aspect of the seat, creating an anthropometric database through measuring the target group and making 3D-scans, to create the shape of the seat. By doing this, she improved pressure distribution and optimized the fit. Her project ended with a fruitful concept.
The aim of this thesis is to take this concept to the next step, validating the incorporation of the research in her design. This is done by creating a design and making a working prototype of an adjustable sitwake seat for beginners with a physical disability, which is easy and quick to adjust. The switch from sitkiting to sitwaking is done to create a more controllable test environment and because the market is easier to penetrate. The end product should be used by both sitwakers and sitkiters. Furthermore, the lifespan of the seat should be extended as long as possible. This is done through a hands-on approach with several iteration cycles.
This thesis is approached with the double diamond method. The classic approach consists of four parts: Discover, define, develop and deliver.
The outcome of the discover and define phase brought valuable insights from extensive desk research, qualitative interviews with the target group, observations and testing comparable products. This led to a list of requirements and wishes. Through rapid prototyping and design by doing, concepts were brought to life to check for feasibility and evaluate with users. This hands-on approach resulted in valuable insights to increase the validity of the design.
The result of the project is a fiberglass seat, adjustable in width and optimized for usability. Emphasis is put on minimizing the footprint and extending its life span. The seat was tested in context to ensure its usability.
Optional straps are integrated to ensure the safety of use for both beginning sitwakers and sitkiters. The final design of the sitwake seat is tailored to the user, lowering the barrier to learning this new sport by decreasing the costs.

The goal of this thesis project was to explore how material originating from thermoplastic composite wind turbine blades (TPC WTB) can be reshaped. The insights gained during exploratory activities were used to design a re-use application. The demonstrator model should inspire people to develop other applications and build upon the foundations laid here.
While wind turbines are a big contribution to the green energy supply, their blades form a problematic waste stream of hard to recycle material. One upcoming blade design innovation aimed at enhancing recycling, that of thermoplastic composites, has opened up a new opportunity in circular end of life strategies: structural re-use through reshaping.
A reference TPC blade was drafted based on insights gained from literature and experts, which defines characteristics like material composition, structure and curvature. These were needed for subsequent material tinkering activities aimed at understanding the material, exploring forming limits and process parameters (Figure 1).
 
These findings, together with material properties and opportunities and threats were combined in a SWOT matrix and design requirements. Blade segmentation was used to make a panel classification table which contains information on panel characteristics which were later used in designing an application. To be able to shape smaller radii, it was decided to split the top layers from the sandwich panel which resulted in much thinner laminates but also more unused material (15 wt%).
After a solid understanding of the material was built, an application could be designed. Standard ideation tools like brainstorming were used but also less standard methods aimed at finding applications yielded diverse application ideas. Following the design vision, one idea was selected: a lamppost. Embodiment of the lamppost based on earlier findings and a norm resulted in a conceptual application design. To prove the feasibility of this application, the strength and stiffness of the post were calculated to comply with the NEN EN 40 norm.
This design was translated to a demonstrator which can be seen in Figure 2. The goal of this demonstrator was to evaluate the performance of the material in reshaping and to simultaneously inspire people to develop new applications, which was validated using interviews. An evaluation of the amount of material used in this application showed that about a third of the yearly supply of WTB material saturates the yearly demand of lamppost.
It can be concluded that the material performs well in reshaping single curved geometries, however reshaping could be problematic for double curved surfaces. The smallest single curved radius tested was 30mm while the largest double curved radius which was tested was 1000mm. A meaningful application which makes use of the material’s value can be made within the reshaping limits while also utilizing a significant amount of blade waste.

Solar generated energy is an alternative to fossil fuel generated energy. However, solar modules have a lifetime and as sales are increasing, waste of solar modules is increasing as well. Cadmium telluride solar cells consist of a material that has a high intrinsic toxicity, cadmium, and a material that is scarce, tellurium. Effective recycling of these materials is therefore needed to lower their impact on the environment. In literature, studies were found that looked at the impacts of the life cycle of CdTe solar cells of which many excluded the recycling stage. As multiple pathways exist for recycling of CdTe solar modules, it is key is to see how they compare to each other. There are a few studies that did include or assessed only a recycling stage. These assessments are all done with distinctive methods, assumptions, and boundaries, making it very hard to compare these results. In literature, a lack incompetent comparison between recycling pathways, including qualitative and quantitative aspect, was identified. The goal of this research was to find qualitative and quantitative trade-offs of potentialEnd-of-Life strategies that are able to lower environmental impacts of CdTe solar modules. By conducting harmonization on existing environmental impact data found in literature and assessing environmental impacts in a Life Cycle Assessment, the quantitative trade-offs were found. Qualitative trade-offs were found in an assessment that include maturity of technology, costs of the technology, and value of recovered material. General quantitative trade-offs that were found were that recycling lowered the environmental impacts, but energy needed for recycling had a large contribution to the remaining impacts. Additionally, the use of chemical recycle processes lowered impacts, however the chemicals that were used gave a large contribution to the impacts remaining due to extraction of chemicals and treatment of wastewater. General qualitative trade-offs could be found in the fact that high recovery values often have high costs related to them. Especially the use of chemicals does retrieve a lot of material, but I expensive. In summary, trade-offs can be found in energy and chemicals use and in costs versus value retrieved. The results of this study add knowledge on the trade-offs of each recycle strategy. This can be weighed against each other and be helpful in deciding which recycle pathways to follow when the incoming CdTe solar module waste needs to be disposed of.

The environmental impacts created by human activity have exceeded planetary boundaries, leading to the need for change towards a circular economy (CE) from a linear economy. The CE aims to reduce environmental impact by focusing on responsible production and consumption. It is achieved by avoiding the outflow of materials and reducing environmental impact as much as possible. Analytical tools such as LCA are necessary to map the environmental impacts of different CE alternatives serving the same product system and assist in finding the most environmentally preferable option. It is essential to make credible, transparent and reproducible assessments of the environmental impact of circular strategies compared with incumbent ways of working. Many databases and software programs used to perform LCAs do not explicitly and transparently solve multifunctionality, which can lead to distorted information and inaccurate decision-making. The report emphasizes the importance of a systematic approach to solve and identify multifunctionality within CE-LCA and improve the reporting of LCAs to make them more transparent. While the CE concept, when implemented in practice by designing products, often leads to reductions in environmental impacts throughout product life cycles, this is not always the case. Design decisions should be based on credible, transparent and reproducible assessments of environmental impacts, and not on assumptions. The focus is on how different choices in modelling recycling and identifying multifunctionality are made in LCA literature, and how reporting can be improved. This report investigates the modelling and reporting of recycling loops in LCA studies that address circular economy systems, with a focus on the ecoinvent database.

This study aims to answer the research question ‘How are recycling loops modelled and reported in LCA studies addressing circular economy systems and in the most widely used LCA database ecoinvent; and how can reporting be improved to better and more transparently communicate conclusions of LCAs to product designers?’

This graduation project delves into the use of Additive Manufacturing (AM) to produce spare parts through a case study of vacuum cleaners. Waste from Electrical and Electronic Equipment (WEEE), including products like vacuum cleaners, challenges the European Union’s (EU) sustainability goals. In 2020 alone, the EU collected an estimated 12.4 million tonnes, representing 10.5 kilograms per person. To address this issue, the “Right to Repair” was adopted. This initiative aims to promote repair as a strategy to slow down WEEE by mandating companies offer 10 years of post-warranty spare parts availability and 15 days of lead time. This mandate challenges companies’ responsiveness due to the extended period of support and limited lead time. Am provides an opportunity to fulfil these requirements while also offering additional benefits such as the digitalisation of the supply chain and reducing the environmental impact of the company’s operations.
The main research goal of the project is the development of a framework for evaluating the suitability of components within a product to be AM printed as spare parts. The framework is established through a literature review across three primary research areas: Priority components (identifying key components for repair activities), Printability (assessing component suitability for AM printing) and Spare Part Suitability (evaluating components’ suitability for supply chain considerations). The proposed framework, encompassing three primary steps, narrows down the components from a complex product to focus on those that present greater AM eligibility. This, in turn, guides the company’s effort in designing, testing and making these eligible parts commercially available.
Step 1. Cut-off criterion: Aims to exclude components defined as not suitable for AM printing, such as standardized elements and electronics.
Step 2. Eligibility Evaluation: Assess components eligibility for AM spare parts printing within the research areas.
Step 3. Component Selection: A top-down approach is employed. It begins with the selection of repair priority components, from his group those deemed AM printable are identified, and finally, components aligned with supply chain suitability are selected.
Takeaways from the conducted research also involve the insights gathered from the conducted framework validation, which involved two Philips vacuum cleaners and the use of Selective Laser Sintering (SLS) for the printing of spare parts. Lastly, this thesis establishes a foundation for the exploration of AM potential in the realm of spare parts manufacturing and future product design.

With the ever increasing number of wirelessly operated connected devices, the environmental consequences that this trend brings about need to be considered. This project has been carried out to explore the possibilities for transitioning industrial IoT sensor nodes into the circular economy.

Wireless sensor nodes are battery powered instruments for monitoring processes and condition of industrial equipment. They need to endure harsh environments and are subjected to critical certification. In general, they are discarded once their internal battery depletes, meaning their embedded potential is lost.
Structuring the analysis of Edge Dynamics’ current product on circular aspects using tools such as HotSpot mapping and the Disassembly Map framework, revealed the disassembly steps and activities that inhibit circular activities such as repair, remanufacturing and recycling. These key components are responsible for a significant fraction of the product’s environmental and economic footprint, or are subjected to a high rate of replacement.

The outcome of the project is a concept sensor node featuring an optimised product architecture. The concept uses a novel way to configure the internal components as such that the key components have the top priority in disassembly. The redesigned sensor node is faster to repair, faster to assemble and disassemble and houses less components. Moreover, the product is made up of less materials and better fits recycling processes as no materials are mixed.
On a system level, circular strategies such as repair and remanufacturing can considerably reduce the environmental impact of the sensor nodes, as giving nodes a second or third lifespan will prevent the need to use virgin materials for the manufacturing of new products.

On a product level, the current product’s key components are sufficiently easy enough to reach and repair that a redesign will only make a significant difference in time savings, and thus costs, on a certain scale. Optimising the sensor node has not increased the embedded footprint. Reusing the circuit boards by for instance repairing sensor nodes can dramatically reduce the lifecycle footprint.
On a material level, using exclusively recycled metals and polymers in the sensor node could reduce its carbon footprint with 4,9% compared to the use of materials containing typical recycling fractions. Moreover, the effectivity of recycling processes can be improved by avoiding the use of mechanical fasteners mixed with dissimilar metals.

Besides the potential reduction of the environmental impact of wireless sensor nodes, a financial incentive is likely at hand as well. Depending on the scale of operation, significant cost reductions can be achieved by faster maintenance and repair when operating a circular business model.

Combining the efforts of each level will lead to the highest potential for sustainable sensor nodes. Edge Dynamics can take a leading role in the industry, offering circular IIoT devices.