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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
231

Planejamento tático da produção agroindustrial com fluxo divergente e produção em dois estágios. / Two-stage tactical planning model for the agri-food industry with divergent process.

Olinto Rodrigues de Arruda Junior 09 April 2014 (has links)
O planejamento tático da produção é importante para as organizações pois permite um correto dimensionamento dos recursos produtivos, para garantir um atendimento adequado da demanda, e influencia nas decisões de produção em médio prazo buscando soluções que colaborem positivamente no resultado operacional. O objetivo deste trabalho é o desenvolvimento de um modelo de planejamento agregado da produção para aplicação na indústria da carne suína que contemple simultaneamente as atividades finais da produção agropecuária e o ambiente de produção da indústria frigorífica. O modelo proposto contempla um sistema produtivo em dois estágios onde o primeiro estágio apresenta um fluxo divergente de produção envolvendo coprodução e o segundo estágio consiste em uma linha de montagem. O sistema apresentado é composto por uma sequência de rotinas de programação, utilizadas para a geração dos dados de entrada e um modelo matemático baseado em programação linear inteira mista cuja função objetivo é maximizar a margem global. As rotinas para geração de dados de entradas foram programadas em Visual Basic For Application e chamadas de Programa de Geração de Padrões. O modelo de programação matemática foi implementado no software LINGO e suas interfaces com as planilhas do Microsoft Excel. A aplicação do modelo para verificação utilizou dados adaptados de uma empresa envolvida no setor e os resultados obtidos permitiram testar a consistência do modelo para a situação específica. A análise dos resultados demonstrou que o modelo gera soluções que estão alinhadas com os objetivos da organização e responde adequadamente a variações nos dados de entrada. / The tactical planning activities are very important for an organization since it allows an anticipated administration of production resources in order to meet the demand and also because it suggests medium term production decisions that can contribute positively to the operational results of the company. This work aims to develop an aggregate production planning model for the pork industry which takes into consideration factors in the meat processing plant as well as in the final step of farming activities. The presented model approaches a two stage production system where the first stage is characterized by a divergent production flow involving coproduction and the second stange is an assemblage line. The entire system is composed by a sequence of routines used to generate some parameters and a mathematical formulation based on mixed integer linear programming in which the objective function aims to maximize the global margin of the organization. The routines used to generate the parameters where implemented in Visual Basic for Application and were called Pattern Generation Program and the mathematic programming were implemented in LINGO and its interfaces with worksheets of Microsoft Excel. The verification of the model used adapted data from a real company in this industry and could test its consistency for this specific situation. The analyzed results demonstrated that the model generates good solution that contribute to the global objective of the company and the model results response to the changes in the parameter as expected.
232

Avaliação de Entrega dos Fornecedores sob a Ótica do Cliente e o PCP desses fornecedores: Um estudo de caso em Empresas do Pólo Industrial de Manaus

Azevedo, Marcos 11 December 2009 (has links)
Made available in DSpace on 2015-04-22T22:11:17Z (GMT). No. of bitstreams: 1 Marcos_Azevedo.pdf: 1641833 bytes, checksum: ea8db673a6d985bfda5c320c067eb052 (MD5) Previous issue date: 2009-12-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work aims at identifying and analyzing the System Planning and Production Control (PCP) in existing companies that provide their inputs to automaker and motorcycle manufacturer correlate the management of PCP with the performance evaluation of delivery of this assembly. First is presented a theory about the planning and production control by addressing the basic concepts and features. Then, the focus is given to the case study conducted in these companies through a research methodology, which sought to verify and show what has been used effectively in terms of PCP, which techniques are used, which reflected the performance of these techniques production companies and which problems related to PCP firms face. A questionnaire was developed as a research tool for obtaining information. The data obtained are analyzed individually and then as a whole. We made a diagnosis on the subject, suggesting the adequacy of those systems to their needs in the short, medium and long term. / A presente dissertação procura identificar e analisar criticamente o Sistema de Planejamento e Controle da Produção (PCP) existente em empresas que fornecem seus insumos para montadora fabricante de motocicletas e correlacionar a gestão de PCP com a avaliação de desempenho de entrega desta montadora. Inicialmente é apresentada uma teoria sobre o planejamento e controle da produção abordando seus principais conceitos e características. Em seguida, o enfoque é dado ao estudo de caso realizado nessas empresas, através de metodologia de pesquisa, onde se procurou verificar e mostrar o que efetivamente vem sendo utilizado em termos de PCP, quais técnicas são utilizadas, quais os reflexos dessas técnicas no desempenho produtivo das empresas e quais os problemas relativos ao PCP que essas empresas enfrentam. Foi elaborado um questionário como instrumento de pesquisa para obtenção das informações. Os dados obtidos são apresentados analisados individualmente e depois no seu conjunto. Realizou-se um diagnóstico sobre o assunto, sugerindo a adequação dos referidos sistemas às suas necessidades nos horizontes de curto, médio e longo prazo.
233

Planejamento e controle da produção na pequena empresa: estudo de caso de fatores intervenientes no desempenho de um empreendimento metalúrgico da cidade de São Carlos-SP / Production planning and control in small business: case study of intervening factors in the performance of a metallurgic company in the city of São Carlos-SP

José Henrique de Andrade 02 October 2007 (has links)
O objetivo geral desta pesquisa foi identificar fatores relacionados ao planejamento operacional da produção que intervêm no desempenho de uma pequena empresa metalúrgica. Como objetivos específicos, pretendeu-se: identificar a existência de políticas e práticas de planejamento na empresa, bem como procedimentos de sua formalização; descrever as características e as atividades do planejamento operacional da produção e os fatores intervenientes em seu desempenho; identificar as características organizacionais específicas da pequena empresa que influenciam o funcionamento do planejamento operacional da produção. Diversos trabalhos da literatura destacam uma relação positiva entre as atividades de planejamento e o desempenho empresarial no âmbito das empresas de pequeno porte e isto motiva o estudo deste assunto. A pequena empresa, devido a suas características específicas tais como restrição de recursos (humanos, financeiros e materiais) e limitado poder de negociação diante de fornecedores, concorrentes e clientes, demonstra dificuldades na sua gestão, entre elas para planejar, controlar e programar a produção de modo a obter um bom desempenho. Para atingir o objetivo proposto, foi desenvolvido um estudo de caso em uma empresa metalúrgica de pequeno porte da cidade de São Carlos/SP, sendo o pesquisador um dos integrantes do quadro de funcionários da empresa, na função de supervisor de PCP, somado à revisão bibliográfica a cerca do tema. Isso, possibilitou o confronto entre a teoria e a prática e a obtenção de conclusões a respeito do tema estudado. Como principais resultados observou-se que: o planejamento operacional carece de informações e análises para a tomada de decisão; o desempenho de uma empresa é influenciado por diversos fatores, e não é possível isolar planejamento e desempenho desses demais fatores, foi verificado um ganho de desempenho expressivo registrado entre os anos de 2002 a 2006 na empresa, porém este trabalho não pôde afirmar que as mudanças realizadas e os fatores do planejamento operacional da produção, PCP, foram influentes no desempenho da empresa. O motivo que impossibilita esta afirmação é o fato de que outros fatores não analisados neste trabalho revelaram-se como de maior impacto sobre o desempenho, por exemplo, a ação da concorrência e a indisponibilidade de recursos de curto prazo em caixa. / The aim of this research was to identify related factors to the operational production planning that intervene in the performance of a small metallurgic company. As specific purposes, it was intended: to identify the existence of politics and practical planning in the company as well as procedures of its formalizing; to describe the characteristics and activities of the operational production planning and intervenient factors in its performance; to identify specific organizational characteristics of the small business that influence the functioning of the operational production planning. Several researches detach a positive relation between planning activities and enterprise performance in the scope of small businesses, which motivates the study of this subject. The small business, due to its specific characteristics such as restriction of resources (human, financial and material) and its limited negotiation approach over suppliers, competitors and customers, demonstrates difficulties in its management, such as to plan, control and program the production in order to get a good performance. To achieve the established goal, a case study was developed in a small metallurgic company in the city of São Carlos/SP, in which the researcher belongs to the employees board of the company as the supervisor of PPC, added up to a bibliographical review about the subject. This made possible the confrontation between the theory and practice and obtainment of conclusions regarding the subject studied. As main results it was observed that: the operational planning lacks information and analyses for decision making; a company\'s performance is influenced by many factors and it is not possible to separate planning and performance from these factors, a significant gain of performance was verified between the years 2002 and 2006 in the company, however this work could not assert that the carried through changes and the factors of the operational production planning, PPC, were influential in the performance of the company. The reason why this affirmation is disabled is the fact that other factors not analyzed in this study were brought out as the biggest impact in performance, for example, the action of the competitors and the unavailability of resources of short term in the company.
234

Desenvolvimento de um núcleo de simulador de eventos discretos para sistemas de manufatura com visualização 3D / Development of a discrete event simulation Kernel for manufacturing systems with 3D visualization

Sena, David Custódio de 25 February 2010 (has links)
É crescente a necessidade de se conhecer e controlar o ambiente fabril. Ao longo do século passado e início deste, várias ferramentas e soluções foram desenvolvidas para suprir essa necessidade. Dentre elas, a simulação desempenha um suporte para o apoio da decisão amplamente utilizada principalmente na indústria manufatureira. A realidade virtual pode ser utilizada no ambiente de simulação como um canal de visualização e interação do usuário com o meio simulado. O objetivo deste trabalho é modelar uma biblioteca do núcleo de simulador de eventos discretos para sistemas de manufatura, com visualização tridimensional, que funcione em ambientes imersivos e não-imersivos. Para tal, as abordagens de três fases e orientada a objetos foram utilizadas com algumas alterações. Para a validação desse desenvolvimento, foram feitas duas simulações de um aplicativo que utiliza os elementos básicos de manufatura e foi feita a coleta de seus resultados que possibilitaram a verificação dos objetivos pretendidos. Por fim, foi feita a análise dos resultados e são apresentadas propostas de trabalhos futuros nesta área. / The need of knowledge and control of the manufacturing environment is continuously growing. Over the last century and the beginning of this, several tools and procedures were designed in order meet those necessities. Among them, simulation is a decision support tool widely used, mainly in the manufacturing industry. Virtual reality can be used in those simulations for user visualization and interaction with the simulated environment. The aim of this research was to model a library for a discrete event simulator core of a manufacturing system, with 3D visualization, that can be used in immersive and non-immersive environments. Two different approaches have been used: the three phases and the object-oriented one. To validate the software development, two simulations were carried out for an application that uses basic elements of manufacturing and production. Data was collected and analyzed in order to check the accomplishment of the research objectives. Finally, a conclusion about the results is presented along with some proposals for future work in this area.
235

Multi-Agent Workload Control and Flexible Job Shop Scheduling

Wu, Zuobao 19 May 2005 (has links)
In the make-to-order (MTO) industry, offering competitive due dates and on-time delivery for customer orders is important to the survival of MTO companies. Workload control is a production planning and control approach designed to meet the need of the MTO companies. In this dissertation, a multi-agent workload control methodology that simultaneously deals with due date setting, job release and scheduling is proposed to discourage job early or tardy completions. The earliness and tardiness objectives are consistent with the just-in-time production philosophy which has attracted significant attention in both industry and academic community. This methodology consists of the order entry agent, job release agent, job routing and sequencing agent, and information feedback agent. Two new due date setting rules are developed to establish job due dates based on two existing rules. A feedback mechanism to dynamically adjust due date setting is introduced. Both new rules are nonparametric and easy to be implemented in practice. A job release mechanism is applied to reduce job flowtimes (up to 20.3%) and work-in-process inventory (up to 33.1%), without worsening earliness and tardiness, and lead time performances. Flexible job shop scheduling problems are an important extension of the classical job shop scheduling problems and present additional complexity. A multi-agent scheduling method with job earliness and tardiness objectives in a flexible job shop environment is proposed. A new job routing and sequencing mechanism is developed. In this mechanism, different criteria for two kinds of jobs are proposed to route these jobs. Two sequencing algorithms based on existing methods are developed to deal with these two kinds of jobs. The proposed methodology is implemented in a flexible job shop environment. The computational results indicate that the proposed methodology is extremely fast. In particular, it takes less than 1.5 minutes of simulation time on a 1.6GHz PC to find a complete schedule with over 2000 jobs on 10 machines. Such computational efficiency makes the proposed method applicable in real time. Therefore, the proposed workload control methodology is very effective for the production planning and control in MTO companies.
236

Propuesta de un proceso básico de gestión de planeamiento y control enfocado en la producción de cacao fino de aroma para mejorar la productividad de los productores de la provincia de La Convención, Cusco

Milla Contreras, Walter Diego, Onofre Vila, Kelly Jazmín 21 August 2019 (has links)
La presente tesis consiste en la investigación exploratoria de la producción del cacao fino de aroma en la provincia de La Convención, departamento del Cusco, desarrollado en el periodo de 1 año, desde Julio 2016 hasta Julio 2017. El diagnóstico de la investigación se obtuvo a través de entrevistas a profundidad a 33 productores de cacao y a la Cooperativa Alto Urubamba. Como primeros resultados se logró identificar que las actividades de producción son empíricas y que han sido heredados de sus antepasados, cuentan con uno de los rendimientos más bajos del Perú con 246 kg/hectárea, no existe una distribución eficiente de los árboles de cacao que permita su sostenibilidad en el tiempo, más del 80% de los productores no realiza la actividad de fermentado pero sí realiza el secado obteniendo cacao convencional, el 20% restante si cumple con el proceso de postcosecha logrando producir un cacao fino de aroma, los productores se encuentran en la línea de pobreza con ingresos mensuales equivalentes a S/ 300 soles aproximadamente. Para abordar esta problemática nuestra investigación propone un modelo de gestión por proceso de Planeamiento y Control de la Producción que permitiría asegurar que el 100% de la producción sea de cacao fino de aroma, incrementaría su productividad en más de 50%, mejoraría su rendimiento a más de 1000 kg/hectárea mediante un Sistema Agroforestal y generaría ingresos per cápita aproximados de S/344.00, permitiendo que los productores se ubiquen fuera de la línea de pobreza. / This thesis consists in the exploratory investigation of the production of fine aroma cocoa in the province of La Convención, department of Cusco, developed in the period of 1 year, from July 2016 to July 2017. The diagnosis of the research was obtained through in-depth interviews with 33 cocoa producers and the Alto Urubamba Cooperative. As first results, it was possible to identify that the production activities are empirical and that they have been inherited from their ancestors, have one of the lowest yields equivalent to 246 kg / hectare, there is no efficient distribution of cocoa trees that allows their sustainability over time, more than 80% of the producers do not carry out the fermentation activity but do the drying process obtaining conventional cocoa, the remaining 20% if they comply with the post-harvest process, producing a fine aroma cocoa, the producers will they are in the poverty line with monthly income equivalent to approximately S/ 350.00 nuevo soles. To address this problem, our research proposes a management model by process of Planning and Production Control that would ensure that 100% of the production is of fine aroma cocoa, increase its productivity by more than 50%, improve its yield to more than 1000 kg / hectare through an Agroforestry System and would generate approximate per capita income of S/344.00 nuevo soles, allowing producers to be located outside the poverty line. / Tesis
237

Optimerad råvarustyrning för sågverksindustrin / Optimized raw material control at sawmills

Johansson, Erik January 2010 (has links)
<p>Ett centralt processteg för sågverk är att sönderdela stockar med olika sågmönster. Vid sönderdelning uppstår ett visst råvaruspill, men genom att använda rätt sågmönster till varje enskild stock kan detta spill minimeras. Som ett steg i att göra detta försorteras därför timmer i ett antal timmerklasser som samlar stockar med liknande egenskaper. Råvarustyrning innebär att välja vilka mönster varje klass ska sågas med, hur stor andel av varje klass som ska sågas med dessa mönster samt att bestämma hur stockar sorteras till klasserna.</p><p>I detta arbete utvecklas ett optimeringsverktyg som angriper problemet att optimera råvarustyrningen med avseende på de framställda produkternas försäljningsvärde. Problemet delas upp i två nivåer där linjärprogrammering kan användas i den ena nivån med syfte att, givet en uppsättning klasser, optimera valen av sågmönster. Linjärprogrammering används eftersom kubikmeterpriset på de sågade trävarorna antas vara konstant med avseende på producerad volym. Den andra problemnivån innebär att optimera timmersorteringen och för detta ändamål implementeras och utvärderas fyra lokalsökningsalgoritmer.</p><p>Genom ett gränssnitt mot användare och databaser kan sågverk ladda in timmerdata, simulerade produktutfall när timmer sågas med olika sågmönster, samt lägsta och högsta tillåtna produktvolymer. Utöver optimering av råvarustyrning kan optimeringsverktyget användas som stöd för att skapa väl underbyggda kundofferter vid nya orderingångar eller väntade förändringar av råvarufördelning.</p><p>Optimeringsverktyget klarar alltid av att hitta det optimala valet av postningar och postningsandelar givet en uppsättning klasser om det existerar minst <em>ett</em> val som uppfyller bivillkoren på framställda produktvolymer. Emellertid visar tester att denna beräkningsrutin gör anspråk på för mycket tid, men sannolikt kan den effektiviseras tillräckligt mycket för att användas skarpt i praktiken. Den bästa lokalsökningsalgoritmen fungerar tillfredsställande i tester, men det krävs mer utvecklingsarbete för att den ska rubriceras som helt klar. Främst i form av att möjliggöra för algoritmen att finna en lösning om sågverkets grundinställda klasser inte kan uppfylla bivillkoren på produktvolymer.Testdatat som används kommer från ett verkligt sågverk, men på grund av brister i detta data kan inga slutsatser dras angående ökad lönsamhet för sågverket genom användning av optimeringsverktyget.</p> / <p>A key process step in sawmills is the sawing of logs into wood, using various sawing patterns. A certain amount of waste always results when sawing, but by using the right sawing pattern for each individual log this waste can be minimized. One way to address this is to presort the incoming logs into a number of sawing classes, where all of these collect logs with similar properties. Raw material control at sawmills involves choosing the patterns to be used on each class, the share of each class to be sawn with the various patterns and also deciding the way logs are assigned to the sawing classes.</p><p>In this work an optimization tool is constructed that addresses the problem of optimizing the raw material control with respect to the sales value of the manufactured products. The problem is divided into two sub-problems where linear programming can be used for one of these sub-problems with purpose to optimize the choices of sawing patterns given a set of classes. Linear programming can be used because the unit price of sawn goods is assumed to be constant with respect to the volume produced. The second sub-problem is to optimize the sorting of logs and in order to do this four different local search algorithms are implemented and evaluated.</p><p>Through an user and database interface the sawmill can access sawlog data, simulated product outcomes and constraints for product volumes. In addition to optimization of the raw material control the optimization tool can help the user to create well-founded quotations whenever new orders arrive or the anticipated raw material distribution changes.</p><p>The optimization tool always manages to find the optimal choice of sawing patterns and shares for a set of sawing classes given the existence of at least one choice that fulfills the constraints for manufactured product volumes. Tests show however, that this computational step requires too much time, but it can probably be streamlined enough to be used in practice.The best local search algorithm serves satisfactory in tests, but needs more development in order to be labeled as finished. Foremost by enabling the algorithm to find a solution even if the sawmill's default sawing classes can not fulfill the product volume constraints. The test data used when evaluating the algorithms come from a real sawmill, but due to shortcomings in the data no conclusions about increased profit for the sawmill can be drawn.</p>
238

Optimerad råvarustyrning för sågverksindustrin / Optimized raw material control at sawmills

Johansson, Erik January 2010 (has links)
Ett centralt processteg för sågverk är att sönderdela stockar med olika sågmönster. Vid sönderdelning uppstår ett visst råvaruspill, men genom att använda rätt sågmönster till varje enskild stock kan detta spill minimeras. Som ett steg i att göra detta försorteras därför timmer i ett antal timmerklasser som samlar stockar med liknande egenskaper. Råvarustyrning innebär att välja vilka mönster varje klass ska sågas med, hur stor andel av varje klass som ska sågas med dessa mönster samt att bestämma hur stockar sorteras till klasserna. I detta arbete utvecklas ett optimeringsverktyg som angriper problemet att optimera råvarustyrningen med avseende på de framställda produkternas försäljningsvärde. Problemet delas upp i två nivåer där linjärprogrammering kan användas i den ena nivån med syfte att, givet en uppsättning klasser, optimera valen av sågmönster. Linjärprogrammering används eftersom kubikmeterpriset på de sågade trävarorna antas vara konstant med avseende på producerad volym. Den andra problemnivån innebär att optimera timmersorteringen och för detta ändamål implementeras och utvärderas fyra lokalsökningsalgoritmer. Genom ett gränssnitt mot användare och databaser kan sågverk ladda in timmerdata, simulerade produktutfall när timmer sågas med olika sågmönster, samt lägsta och högsta tillåtna produktvolymer. Utöver optimering av råvarustyrning kan optimeringsverktyget användas som stöd för att skapa väl underbyggda kundofferter vid nya orderingångar eller väntade förändringar av råvarufördelning. Optimeringsverktyget klarar alltid av att hitta det optimala valet av postningar och postningsandelar givet en uppsättning klasser om det existerar minst ett val som uppfyller bivillkoren på framställda produktvolymer. Emellertid visar tester att denna beräkningsrutin gör anspråk på för mycket tid, men sannolikt kan den effektiviseras tillräckligt mycket för att användas skarpt i praktiken. Den bästa lokalsökningsalgoritmen fungerar tillfredsställande i tester, men det krävs mer utvecklingsarbete för att den ska rubriceras som helt klar. Främst i form av att möjliggöra för algoritmen att finna en lösning om sågverkets grundinställda klasser inte kan uppfylla bivillkoren på produktvolymer.Testdatat som används kommer från ett verkligt sågverk, men på grund av brister i detta data kan inga slutsatser dras angående ökad lönsamhet för sågverket genom användning av optimeringsverktyget. / A key process step in sawmills is the sawing of logs into wood, using various sawing patterns. A certain amount of waste always results when sawing, but by using the right sawing pattern for each individual log this waste can be minimized. One way to address this is to presort the incoming logs into a number of sawing classes, where all of these collect logs with similar properties. Raw material control at sawmills involves choosing the patterns to be used on each class, the share of each class to be sawn with the various patterns and also deciding the way logs are assigned to the sawing classes. In this work an optimization tool is constructed that addresses the problem of optimizing the raw material control with respect to the sales value of the manufactured products. The problem is divided into two sub-problems where linear programming can be used for one of these sub-problems with purpose to optimize the choices of sawing patterns given a set of classes. Linear programming can be used because the unit price of sawn goods is assumed to be constant with respect to the volume produced. The second sub-problem is to optimize the sorting of logs and in order to do this four different local search algorithms are implemented and evaluated. Through an user and database interface the sawmill can access sawlog data, simulated product outcomes and constraints for product volumes. In addition to optimization of the raw material control the optimization tool can help the user to create well-founded quotations whenever new orders arrive or the anticipated raw material distribution changes. The optimization tool always manages to find the optimal choice of sawing patterns and shares for a set of sawing classes given the existence of at least one choice that fulfills the constraints for manufactured product volumes. Tests show however, that this computational step requires too much time, but it can probably be streamlined enough to be used in practice.The best local search algorithm serves satisfactory in tests, but needs more development in order to be labeled as finished. Foremost by enabling the algorithm to find a solution even if the sawmill's default sawing classes can not fulfill the product volume constraints. The test data used when evaluating the algorithms come from a real sawmill, but due to shortcomings in the data no conclusions about increased profit for the sawmill can be drawn.
239

Capability to Promise (CTP) Handling Strategy in SAP

Laoniphon, Patriya, Yu, Wenyi January 2011 (has links)
Nowadays, many companies attempt to adapt their production planning and strategy to make order fulfillment more flexible. In manufacturing, the capacity and capability constraints are key factors which need efficient production planning for controlling service level and minimizing inventory cost. This thesis focuses on looking for the economic and efficient strategies for Capability to Promise or CTP handling. This strategy is proposed to work for Low Volume/High Mixed product manufacturing. Moreover, SAP is used as Enterprise Resource Planning (ERP) system for steering the CTP handling strategies in order to increase automated order handling regarding cost efficiency. The results of this research are both concepts and implementations on how to set CTP handling by using SAP, regarding the demand uncertainty environment in Make to Order (MTO) fulfillment.
240

KORTSIKTIG PRODUKTIONSPLANERING I MINDRE FJÄRRVÄRMESYSTEM : En studie vid Strängnäs Energi AB

Erneby, Robin January 2012 (has links)
District heating covers around 80 % of the heating demand in apartment buildings and 10 % in single-family homes in Sweden. In the year 2010 the total input of energy to the Swedish district heating grids was about 70 TWh, which corresponds to 11 % of the total energy input to the whole energy system in the country. Through the combined production of heat and power the CHP-plants often reaches an efficiency of 90 % from energy in the fuel to produced heat and power. In order to keep the efficiency high it is important for the owners of the plant to have good knowledge about the plants performance at different operation points. Strängnäs Energi AB initiated this diploma work together with FVB Sverige ab in order to come up with a program for short term planning of the production of heat and power at the company´s CHP-plant. The work consists of three main parts. The first part is an introduction to district heating and optimization of such systems and it also handles a short explanation of the district heating system in Strängnäs. The second part covers the performance tests that have been done at Strängnäs Energi AB´s CHP-plant. The performance tests were carried out in order to investigate how the plant is operating. The results from the tests show that the efficiency of the plant is very poor. This has its explanation in the losses in forms of combustible content in the bottom ash, which in some cases reaches over 4 %. The problems with the combustion have been known for a while at Strängnäs Energi AB, but they did not have any calculated value of the efficiency. The company is working hard in order to come up with good solutions for the combustion and therefore this is not included in the diploma work. Instead the third part of the diploma work is focused on developing of a model for short term production planning. The model was made in MS Excel and it consists of a number of power and mass balances over one day. The key to the calculations in the model is the calculation of the alfa-value. The alfa-value together with the power in the hot water condenser gives an iterative calculation. The hot water accumulator is then either charged or discharged depending on current electrical price, demand of district heating and the level in the accumulator. The results from the simulations done with the model shows that it is possible for Strängnäs Energi AB to earn between 0 – 20 000 SEK during one day if they operate their plant as suggested in the model.

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