This diploma thesis focuses on the unconventional method of metal separation, namely on the cutting technology based on the plasma arc. The introductory part deals with studies which focus on the given issue from a theoretical point of view. The core of the work rests in the practical part which is dedicated to the production of samples using a plasma burning machine called Hypertherm HPR 260. The burned samples are monitored and assessed for the surface quality and dimensional accuracy for every created part. The final part of the work is dedicated to the techno-economic assessment of the burned parts. In the end, the evaluation of the attained results is made.

Increasing resource efficiency by utilising secondary raw material is one of the key characteristics of a circular economy. Textile dust fibre, a waste generated from textile mechanical recycling has the prospect to be utilised as secondary raw material for producing novel material: textile paper suitable for packaging and other applications. A comparative Life Cycle Assessment (LCA) of carrier bags made from one ton of virgin paper, recycled paper and novel textile paper (~22584paper bags with grammage of 100 g/m2 and same dimensions for all 3 types of bags) showed that textile paper bag is more environmentally friendly in terms of carbon footprint. The largest environmental contributors were energy consumed in the pulping and paper making processes, followed by the use of adhesives and printing ink in the conversion process of paper to papercarrier bags. A comparative Techno-economic Assessment (TEA) was carried out for the operating cost of producing the three selected carrier bag types. The analysis conveyed that textile paper bags are more economically attractive, mainly due to the partial substitution of paper fibre with low-cost textile dust fibre. Furthermore, a simple tool was developed with an attempt to assess and compare materials suitability for the circular economy considering life cycle thinking and business perspectives. Assessment of textile paper using the Circular material assessment tool indicated that there is still scope for improvement on the following circularity characteristics of circular material: scarcity of raw material, local supply of resources, clean and non-toxic resources. Textile paper material scored high in the following circularity characteristics: secondary raw material, industrial symbiosis, recycling, resource efficiency in manufacturing and use. In the final step, the textile paper bag was eco-designed through the combined and iterative LCA and TEA approach with the aim to achieve improved scores as a circular material. In order to understand the overall sustainability advantages and trade-offs, further research is recommended on different textile dust fibre grades as well as textile paper performance based on mechanical properties. It is also recommended to investigate textile paper in other applications like one time fashion clothes, reusable paper bags as textile hangers etc.

Research has shown that three-phase balancing alone can improve the operation of secondary distribution networks and that the addition of energy storage to the phase balancing power electronics further helps to alleviate the negative effects of phase unbalances. However, less attention has been paid to the economic potential of said technologies and particularly for loadside implementation. It appears that the deployment of phase balancers, with or without energy storage, is indeed hampered by uncertainty related to its economic feasibility, despite both technologies being commercially available. This thesis therefore aims to assess and compare the economic feasibility of the two configurations for peak shaving purposes in the context of residential property loads in Sweden. The assessment was performed using a specially developed deterministic techno-economic model taking into consideration historical load data from three Swedish real estate, cost estimations for a range of alternatives used when sizing the systems, applicable tariffs and fees for electricity and its distribution as well as technical parameters such as the capacities and efficiencies of the involved components. A novel approach was taken by linearly extrapolating the three load profiles into three sets of 91 synthesized load profiles to enable a larger dataset for analysis. The net present values generated for each set were then graphed and analyzed per original real estate. The results showed that both configurations can be economically feasible, but only under certain conditions. A phase balancer alone was found to be feasible for real estate whose peak currents are distinctly unbalanced and exceed 50 A, with the best expected rate of return for profiles exceeding 63 A since they enable a tariff switch. The combined system was found to be even more contingent on the tariff switch and therefore only feasible for peaks above 63 A. A substantial difference in the initial investment further makes the single phase balancer the preferred choice, unless the discount rate is as low as 2 % or less. On this basis, potential investors need to assess the state of unbalance of their loads and perform their own calculation based their load profile, cost of capital and applicable tariffs. / Tidigare forskning har visat att fasbalansering enskilt kan förbättra driften hos lokala distributionsnät och att ett batterisystem i tillägg till fasbalanserarens kraftelektronik ytterligare kan minska de negativa effekterna av fasobalanser. Däremot har mindre uppmärksamhet riktats mot den ekonomiska genomförbarheten hos dessa teknologier och i synnerhet för implementation på lastens sida av elmätaren. Det tycks vara så att spridningen av fasbalanserare, med eller utan energilagring, hindras av osäkerheten kring dess ekonomiska potential trots att båda teknologierna är kommersiellt tillgängliga. Detta arbete ämnar därför att värdera och jämföra den ekonomiska nyttan hos de två konfigurationerna vid toppreducering av fastighetselen i svenska bostadsfastigheter. Värderingen utfördes med hjälp av en särskilt utvecklad deterministisk tekno-ekonomisk modell som beaktade historiska lastdata från tre svenska fastigheter, kostnadsuppskattningar för en uppsättning av konfigurationer som användes vid dimensionering av systemen, applicerbara tariffer och avgifter för elektricitet och dess distribution samt tekniska parametrar såsom kapaciteter och verkningsgrader för de olika komponenterna. Ett annorlunda tillvägagångssätt tillämpades vidare för att utöka datamängden genom linjär extrapolation av lastprofilerna, vilket resulterade i tre uppsättningar av 91 syntetiserade lastprofiler. Nettonuvärdet beräknades följaktligen för varje profil och investeringsalternativ för att sedan plottas och analyseras per ursprunglig fastighet. Resultaten visade att båda konfigurationerna kan uppvisa lönsamhet, men endast under särskilda förutsättningar. Den enskilda fasbalanseraren bedömdes som lönsam för fastigheter vars strömtoppar är påtagligt obalanserade och som överstiger 50 A, med största möjliga lönsamhet för profiler som överstiger 63 A då dessa möjliggör ett tariffbyte. Det kombinerade systemets lönsamhet bedömdes vara ännu mer beroende av tariffbytet och därför endast lönsamt för strömtoppar över 63 A. En betydligt större grundinvestering för det kombinerade systemet gör vidare att den enskilda fasbalanseraren i regel är att föredra, såvida inte kalkylräntan är så låg som 2 % eller mindre. Baserat på detta uppmanas potentiella investerare att undersöka balanstillståndet hos deras laster och att utföra en egen kalkyl baserat på deras specifika last, kapitalkostnad och nätföretag.

<p dir="ltr">In our daily lives, we rely on a multitude of discrete products to meet our needs. Traditional product design approaches have primarily focused on economic and technical aspects, often overlooking the pressing environmental and social challenges facing society. Recognizing the limitations of our ecological systems to cope with the waste generated by our current industrial processes, there is a growing need to anticipate the potential consequences of product design across technical, economic, environmental, and social dimensions to pave the way for a sustainable future. One promising strategy within this context is the integration of sustainability principles into optimization-based design models that consider a product's entire life cycle. While there have been previous efforts to optimize product life cycles, a comprehensive exploration of optimization-based design methods with a focus on multiple objectives for discrete products is essential. This dissertation explores the integration of sustainability principles with optimization-based design by taking the electric traction motor used in electric vehicles as a case study. This complex and environmentally significant technology is ideal for investigating the tradeoffs and benefits of incorporating sustainability objectives into the design process.</p><p dir="ltr">The key tasks undertaken in this study are as follows:</p><ul><li>Development of a parametric design and optimization framework for a surface-mounted permanent magnet synchronous motor. In this task, a special emphasis is placed on reducing reliance on materials with a high supply risk, such as rare earth elements.</li><li>Creation of a parametric life cycle assessment model that combines life cycle assessment and optimization-based design to minimize a single-score environmental impact. This model offers insights into the environmental performance of product design and underscores the importance of minimizing environmental impact throughout a product's life cycle.</li><li>Integration of a life cycle costing model, incorporating techno-economic assessment and total cost of ownership perspectives, into the parametric life cycle assessment and optimization-based design models. This model is used to minimize levelized production and driving costs, shedding light on the trade-offs within this family of cost metrics and the optimization of manufacturing systems for motor production.</li><li>Proposal of a circular economy model/algorithm to assess the advantages of integrating the circular economy paradigm during the early design phase. All the mentioned objective functions are considered to study the impacts of applying the circular economy paradigm.</li></ul><p dir="ltr">The contributions of this research can be summarized as follows:</p><ul><li>Utilized a diverse array of analytical methodologies to parameterize the design process of a motor, incorporating the integration of Life Cycle Assessment (LCA) and Techno-Economic Analysis (TEA) models, as well as the incorporation of disassembly planning for informed decision-making in the early stages of design.</li><li>Proposed a generalized objective function denoted as the Supply Risk-equivalent (SR-eq.), aimed at mitigating the risks associated with the dependency on critical materials in product manufacturing.</li><li>Introduced a novel approach for visualizing non-dominated solutions within a multi-objective framework, with experimentation conducted on up to six distinct objectives.</li><li>Substantiated the significance of decarbonizing the electric grid while maintaining competitive cost structures, the importance of advancing non-destructive evaluation (NDE) procedures for assessing the condition of end-of-life (EoL) subassemblies, and optimizing the collection rate of EoL motors.</li></ul><p dir="ltr">Demonstrated that the optimization of technical metrics as surrogate indicators for economic and environmental performance does not necessarily yield designs that are concurrently optimal in economic and environmental terms.</p>