6,292 research outputs found

    A Stochastic Simulation-Optimization Method for Generating Waste Management Alternatives Using Population-Based Algorithms

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    While solving difficult stochastic engineering problems, it is often desirable to generate several quantifiably good options that provide contrasting perspectives. These alternatives should satisfy all of the stated system conditions, but be maximally different from each other in the requisite decision space. The process of creating maximally different solution sets has been referred to as modelling-to-generate-alternatives (MGA). Simulation-optimization has frequently been used to solve computationally difficult, stochastic problems. This paper applies an MGA method that can create sets of maximally different alternatives for any simulation-optimization approach that employs a population-based algorithm. This algorithmic approach is both computationally efficient and simultaneously produces the prescribed number of maximally different solution alternatives in a single computational run of the procedure. The efficacy of this stochastic MGA method is demonstrated on a waste management facility expansion case

    Stochastic Modelling to Generate Alternatives Using the Firefly Algorithm: A Simulation- Optimization Approach

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    In solving many practical mathematicalprogramming applications, it is generally preferable to formulateseveral quantifiably good alternatives that provide very differentapproaches to the particular problem. This is because decisionmakingtypically involves complex problems that are riddled withincompatible performance objectives and possess competingdesign requirements which are very difficult – if not impossible –to quantify and capture at the time that the supporting decisionmodels are constructed. There are invariably unmodelled designissues, not apparent at the time of model construction, which cangreatly impact the acceptability of the model’s solutions.Consequently, it is preferable to generate several alternativesthat provide multiple, disparate perspectives to the problem.These alternatives should possess near-optimal objectivemeasures with respect to all known modelled objective(s), but befundamentally different from each other in terms of the systemstructures characterized by their decision variables. This solutionapproach is referred to as modelling to generate-alternatives(MGA). This paper provides a biologically-inspired simulationoptimizationMGA approach that uses the Firefly Algorithm toefficiently create multiple solution alternatives to stochasticproblems that satisfy required system performance criteria andyet remain maximally different in their decision spaces. Theefficacy of this stochastic MGA method is demonstrated using awaste facility expansion case study

    Decision support methodology for sustainable smart energy systems integration

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    The global demand for energy is continuously increasing, and the carbon dioxide production related to the energy sector represents a large share of the overall anthropogenic greenhouse gas (GHG) emissions, since most of the energy needs are still provided by fossil fuels. To achieve the energy efficiency targets set by EU for the 2030 an energy transition towards more sustainable energy sources is required. The challenge will be the integration of different energy sectors in a smart energy system (SMES). Adopting a circular economy perspective it will be possible to turn the view on waste starting considering them as an energy source allowing more interactions between different stakeholders while exploiting technologies for the reduction of the environmental impact. This change in perspective needs also a change in the paradigm while taking decision on the implementation of this kind of interventions. The aim of this thesis is to fill the gaps in the development of decision support tools aiding the stakeholders in those interventions where SMES are implemented with developing and sustainable solutions

    Improving sustainability of energy intensive sectors through multi-objective models

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    openGlobal energy consumption and the related carbon dioxide emissions, which represent a large share of the overall anthropogenic greenhouse gas production, are continuously increasing since most of the energy needs are still provided by fossil fuels, thus constituting one of the main issues to be addressed in the climate change mitigation agenda. To achieve the Paris Agreement’s ambitious objectives, an energy transition towards sustainable energy systems based on the new smart energy system (SES) paradigm is needed, thus integrating the various energy sources, vectors and needs within the sectors (electricity, heating, cooling, transport, etc.). However, optimal planning, design and management of complex integrated systems such as SES require to make use of proper decision support models based on multi-objective optimization techniques, since a sustainability analysis intrinsically involves environmental, economic and social aspects. Furthermore, a SES project involves several stakeholders, each driven by different and often conflicting objectives, which should be considered within such models, to remove some relevant barriers to the energy transition. Focusing on the improvement of the sustainability of the energy-intensive sectors, the main objective of this thesis is thus the development of a decision support framework based on multi-objective optimization with the aim to support the decision makers in the planning, design and management of integrated smart energy systems, while considering the different involved stakeholders. The proposed model, composed by three main phases (namely investigative, design and decision-making), has been developed by steps via its application on case studies belonging to two main topics concerning the improvement of the sustainability performance of energy-intensive sectors through the implementation of the smart energy system concept. The first main topic is representative of the context of industrial districts and concerns their sustainable energy supply based on technical solutions specifically designed for cluster of firms, allowed by geographical proximity. The other one concerns the synergic integration between industrial and urban areas, through the recovery of waste energy from industrial processes to feed municipal district heating with a carbon-free source. The case studies have been selected, within the opportunities available in the local territorial context, not only because fit for the implementation of the smart energy system concept, but also due to their suitability for the implementation of different phases of the proposed decision support system (DSS).Dottorato di ricerca in Scienze dell'ingegneria energetica e ambientaleopenCiotti, Gelli

    The modelling of future energy scenarios for Denmark

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    Municipal solid waste management system: decision support through systems analysis

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    Thesis submitted to the Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia for the degree of Doctor of Philosophy in Environmental EngineeringThe present study intends to show the development of systems analysis model applied to solid waste management system, applied into AMARSUL, a solid waste management system responsible for the management of municipal solid waste produced in Setúbal peninsula, Portugal. The model developed intended to promote sustainable decision making, covering the four columns: technical, environmental, economic and social aspects. To develop the model an intensive literature review have been conducted. To simplify the discussion, the spectrum of these systems engineering models and system assessment tools was divided into two broadly-based domains associated with fourteen categories although some of them may be intertwined with each other. The first domain comprises systems engineering models including cost-benefit analysis, forecasting analysis, simulation analysis, optimization analysis, and integrated modeling system whereas the second domain introduces system assessment tools including management information systems, scenario development, material flow analysis, life cycle assessment (LCA), risk assessment, environmental impact assessment, strategic environmental assessment, socio-economic assessment, and sustainable assessment. The literature performed have indicated that sustainable assessment models have been one of the most applied into solid waste management, being methods like LCA and optimization modeling (including multicriteria decision making(MCDM)) also important systems analysis methods. These were the methods (LCA and MCDM) applied to compose the system analysis model for solid waste. The life cycle assessment have been conducted based on ISO 14040 family of norms; for multicriteria decision making there is no procedure neither guidelines, being applied analytic hierarchy process (AHP) based Fuzzy Interval technique for order performance by similarity to ideal solution (TOPSIS). Multicriteria decision making have included several data from life cycle assessment to construct environmental, social and technical attributes, plus economic criteria obtained from collected data from stakeholders involved in the study. The results have shown that solutions including anaerobic digestion in mechanical biological treatment plant plus anaerobic digestion of biodegradable municipal waste from source separation, with energetic recovery of refuse derived fuel (RDF) and promoting pays-as-you-throw instrument to promote recycling targets compliance would be the best solutions to implement in AMARSUL system. The direct burning of high calorific fraction instead of RDF has not been advantageous considering all criteria, however, during LCA, the results were the reversal. Also it refers that aerobic mechanical biological treatment should be closed.Fundação para a Ciência e Tecnologia - SFRH/BD/27402/200

    Green Technologies for Production Processes

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    This book focuses on original research works about Green Technologies for Production Processes, including discrete production processes and process production processes, from various aspects that tackle product, process, and system issues in production. The aim is to report the state-of-the-art on relevant research topics and highlight the barriers, challenges, and opportunities we are facing. This book includes 22 research papers and involves energy-saving and waste reduction in production processes, design and manufacturing of green products, low carbon manufacturing and remanufacturing, management and policy for sustainable production, technologies of mitigating CO2 emissions, and other green technologies
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