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Utvärdering och analys av batchstorlekar, produktsekvenser och omställningstider / Evaluation and analysis of batch sizes, production sequences and setup timesLundberg, Jesper, Mehtonen, Ronja January 2015 (has links)
Volvo GTO is one of the strongest brands in the truck industry, with a long and proud history of world-leading innovations. The factory in Skövde produces diesel engines of various sizes to Volvo GTO. The project has been carried out on the processing part of grovdel crankshaft. Where the objective was to construct a simulation model that reflects flows 0, 1 and 2 on the crankshaft grovdel order to produce the best driving style for the size of the batches and sequences, focusing on PIA, between the stock and conversion-up times. A theoretical study intervention gave knowledge to the methodology to ensure that the data is collected and processed correctly. The data were collected in an Excel document, which was integrated with the simulation model for an overview and adjustments would be possible. The simulation program, Siemens Plant Simulation 12 used in the construction of the complex model of the three flows, which where verified and validated against the real flows. Optimization on the simulation model was made with a high and a low demand for crankshafts. Several objects were taken into consideration as: minimal waiting processing Findel, minimal setup time and minimal total-PIA from a truly viable perspective. The optimization showed a possible production planning in order to best be able to run such large batches as possible with reduced readjustment time and for delays of production in processing rawflows to not occur in the refined flow. For maximum capacity in the company there are two different optimal solutions one solution focused on reducing setup time and the second solution to minimize the number of additional production hours per week. Discrete simulation of production flows are being used to support production planning and simulation model is created for the continued use of the Volvo GTO, either in simulation group or future researches and theses in collaboration with the University of Skövde. The project objectives were achieved with good results and resulted as a standing basis for future planning of batches and sequences of processing crankshaft Volvo GTO.
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Optimeringsmodell för produktallokering : Baserat på processkartläggning och klassificering, en fallstudieÖstlund, Erika January 2017 (has links)
Lagerhantering anses vara en betydelsefull aktivitet som företag måste ta sig an, då förbättrade metoder kan ha direkt påverkan på resultatet. Produktallokering inom lagret är en av de vitala delarna inom lagerplanering. Detta arbete är en fallstudie där fallet är ett lager hos ett producerande företag med det övergripande syftet att undersöka hur en optimeringsmodell för lagerhantering kan hjälpa organisationer med dess lagerhantering genom att studera rådande processer och utifrån det skapa en optimeringsmodell för att beräkna optimal lagerallokering. Studien har utförts genom en mixad metod, uppdelad i en kvantitativ- och en kvalitativ fas, då forskning hävdar att nyckeln till framgång för effektiv lagerhantering är att matcha policyn med lagrets layout och de ordertyper som lagret hanterar, för att anpassa optimeringsmodellen utifrån det givna fallets policy, lagerlayout och ordertyper. I den första fasen genomfördes en processkartläggning för att bygga upp för optimeringens utformning. Den andra fasen gick ut om att matematiskt beskriva samma problemuppställning och modellera problemet på insamlad kvantitativ data. I processkartläggningsfasen identifierades de två differentieringskriterierna omsättning i enheten sålda paket och förädling i enheten produktionskostnad. Målet med utförd klassificering var att ta fram vilka unika produkter som bör behandlas differentierat och erhålla tilldelad lagring, vilket var en förbättringsmöjlighet funnen i nulägesbeskrivningen. Totalt togs det fram 93 produkter att placera ut på någon av de 220 lagringsplatserna med målet att minimera körsträckan med truck. Jämförelse av målfunktionsvärden mellan optimaluppsättning enlig modell och dagens uppsättning, påvisade en teoretisk besparing av antal körda meter på 35 %. Studiens resultat har påvisat att matematisk modellering och linjärprogrammering går att använda för lagerallokeringsproblem för att optimera produktallokeringen, där den matematiskmodellen baserats på fallspecifika egenskaper. Modellens resultat förväntas underlätta ett antal av de problem som noterats vid kartläggning av lagerhanteringsprocesserna. / Inventory management is considered to be an important activity that companies need to accomplish as improved methods directly can affect the final result. Product allocation within the warehouse is one of the vital parts of inventory management. This report is a case study where a warehouse of a manufacturing company is considered the case. The overall purpose is to investigate how a optimization model can help organizations with their inventory management, by first studying existing processes and based on that create the model to calculate optimal inventory allocation. The study has been conducted through a mixed method, divided into a quantitative and qualitative phase, as research claims that the key to the success of efficient inventory management is to match the layout of the warehouse case policy, stock layout and order types in order to customize the optimization model. In the first phase, a process mapping was conducted to build the optimization design. The second phase was based on mathematically describing the same problem setup, and then to model the problem with collected data. In the process-mapping phase, two differentiation criteria were identified as units sold packages and the unit production cost. The purpose of the classification was to identify which unique products that should be treated differently and receive assigned storage, which was an improvement opportunity found in the case description. A total of 93 products were placed on one of the 220 storage sites, with the aim of minimizing the mileage by truck. Comparison of target function values between the optimal set-up model and the current set, demonstrated a theoretical saving of the number of driven meters of 35%. The study results have shown that mathematical modeling and linear programming can be used for inventory allocation problems to optimize product allocation, where the mathematical model is based on case-specific properties. The model's results are expected to facilitate a number of the problems noted in mapping inventory management processes.
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On multilayered system dynamics and waves in anisotropic poroelastic mediaParra Martinez, Juan Pablo January 2016 (has links)
The mechanical and acoustic anisotropy of media is a governing factor in the behaviour of multilayered systems including such media. The understanding of the mechanisms conditioning the dynamic behaviour of multilayered systems is of paramount importance. In particular, the intrinsic anisotropy of poroelastic media presents a potential for the optimal design of systems for multifunctional performances. Indeed, these multilayered systems are bound by stiffness, thermal and acoustic performance constraints in simultaneously. A plane wave method is presented to study the influence of material orientation in the dynamic behaviour of multilayered systems composed of anisotropic poroelastic media. The method is applied to a system composed of an anisotropic open-celled melamine foam core in between two metal sheets. This particular multilayered configuration allows to shed light on phenomena intrinsic to layers composed of anisotropic poroelastic materials, such as the frequency shift of the fundamental resonance of the panel, or the compression-shear coupling effects taking place in the poroelastic core layers. The latter phenomena is of particular importance, as it is evidenced on the unconventional polarisation of waves in anisotropic poroelastic media. Finally, the method is adapted to the optimisation of multilayered systems for acoustic performance. the design variables are consequently the core material orientations with respect to the global coordinate system. The solutions to the optimisation problem are analysed in terms of dynamic behaviour, thus allowing to correlate acoustic performance of the overall structure, and the response of each individual layer. / <p>QC 20161110</p>
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Energirenovering av flerbostadshus från miljonprogrammet genom LCC-optimering : En fallstudie av två byggnader i Linköping, Sverige / Energy Renovation of Multi-family Buildings from the Million Programme Using LCC-Optimisation : A Case Study of two Buildings in Linkoping, SwedenKindesjö, Viktoria, Nordqvist, Linda January 2019 (has links)
The content of greenhouse gases in the atmosphere is increasing resulting in climate change and efforts to stop the negative trend need to be intensified. The energy use in the Swedish residential and service sector constitutes 40 % of the total energy use of 378 TWh in the country. Nationally there is a target to reduce the energy use per heated area with 20 % to 2020 and 50 % to 2050. Energy renovation of buildings from the Million Programme is foreseen to be able to contribute to achieving the targets owing to the large building stock and energy efficiency potential. In the master thesis cost optimal energy renovation strategies are investigated for two multi-family buildings in Linkoping built during the Million Programme, one with an unheated attic and one with a heated attic. The thesis is carried out by using life-cycle cost optimisation (LCC-optimisation) by utilising the software OPERA-MILP, developed at Linkoping University. The aim of the thesis is to obtain the energy renovation strategy that is optimal from an LCC-perspective and to investigate the energy reduction and LCC. Optimal energy renovation strategies are also investigated for energy renovation to levels of the Energy Classes of the National Board of Housing, Building and Planning in Sweden and the stricter limits for nearly zero-energy buildings (NZEB) that will likely come into force in 2021. Greenhouse gas emissions and primary energy use are also investigated for the different cases with the purpose of putting energy renovation in relation to climate impact. Local environmental factors are used for district heating while electricity is assigned values based on the Nordic electricity mix and Nordic marginal electricity respectively. The current LCC and annual energy use is 2 945 kSEK and 133 MWh for the building with an unheated attic and 3 511 kSEK and 162 MWh for the building with a heated attic. The result shows that LCC can be reduced by approximately 70 kSEK and 90 kSEK respectively. The optimal solution constitutes of a window change from windows with U=3,0 W/m2°C to windows with U=1,5 W/m2°C and results in a reduction of the energy use by 13 % and 15 % respectively. LCC increases with 240 kSEK for the building with unheated attic and decreases with 18 kSEK for the other building when Energy Class D is reached. Energy Class C is attained through an increase in LCC by 300 – 590 kSEK and Energy Class B through an increase by 1610 – 1800 kSEK. It is not possible to reach Energy Class A or the future requirements for NZEB (55 kWh/m2Aheated) with the energy renovation measures that are implemented in OPERA-MILP. The largest energy reduction that can be attained is approximately 60 %. The most cost optimal insulation measure is additional insulation of the attic floor/pitched roof followed by additional insulation of the ground concrete slab. It was shown to be more cost efficient to change to windows with U=1,5 W/m2°C in combination with additional insulation compared to changing to windows with better energy performance. For greater energy savings additional insulation on the inside of the external wall is applied, while insulation on the outside of the external wall is never cost optimal. To reach Energy Class B installation of HRV is required which gives a large increase in cost. Less extensive energy renovation is needed to reach the energy classes for the building with heated attic compared to the building with unheated attic. The annual use of primary energy in the reference case is 22 MWh for the building with an unheated attic and 26 MWh for the building with a heated attic. The emissions of greenhouse gases are 18 tonnes CO2e and 22 tonnes CO2e per year respectively when the emission factor of the Nordic electricity mix is applied and 20 tonnes CO2e and 25 tonnes CO2e respectively when the Nordic marginal electricity is applied. The yearly primary energy use can be reduced with up to 7 MWh through energy renovation. When the energy renovation leads to an increase in electricity use the primary energy can however increase with up to 12 MWh. The yearly greenhouse gas emissions can be decreased with up to 14 tonnes CO2e. When Nordic marginal electricity is applied to estimate the emissions of greenhouse gases for an energy renovation strategy that leads to an increase in electricity use the result is less beneficial from a climate perspective compared to when Nordic electricity mix is applied.
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Värme- och massflöde i precisionsgjuteri : Optimering och undersökning av simuleringsparametrar för precisionsgjutningKuivamäki, Daniel, Mohseni, Mohammad January 2019 (has links)
För att kunna prediktera fel under processen precisionsgjutning, används simulering som ett verktyg att bestämma hur detaljer skall gjutas. Det finns flertalet parametrar som är möjliga att manipulera eller ändra. För att komma så nära ett verkligt scenario som möjligt behöver dessa parametrar optimeras mot verkligheten. Syftet med detta arbete är att analysera faktorer som påverkar värmeöverföring för att sedan presentera optimeringsförslag åt TPC Components AB mot de gjorda mätningarna. Detta görs för att kunna förutsäga till exempel hur snabbt ett föremål kyls i processen och hur det påverkar det slutgiltiga resultatet. Resultat från de optimerade simuleringarna jämförs mot ett praktiskt försök och även TPC Components tidigare standard utvärderas mot arbetets optimerade simuleringar. En viktig fråga är att undersöka varför simuleringsprogrammet inte blir identiskt med verkligheten och hur detta undersöks. Känslighetsanalyser utgör därmed en stor del av arbetet och det är av vikt att undersöka enskilda parametrar för att få en uppfattning om vad som påverkar resultatet och vad som går att bortse från. Resultatet av arbetet visar att ändrade parametrar för indata vid precisionsgjutning i TPC Components AB:s vakuumprocess har resulterat i en mer pålitlig simulering. Simuleringen bygger nu på vetenskapliga bevis och faktiska uppmätningar under processen för att kunna simulera så likt verkligheten som möjligt. Arbetet resulterar i att färre gjutförsök innan godkänt tillvägagångssätt för nya detaljer behövs, då simulering kommer att visa resultat närmare verkligheten. Arbetet har förbättrat TPC Components simuleringsarbete vilket kommer påverka både arbetstid, kostnader och miljö på ett positivt sätt. / Simulation of investment casting play a big role for prediction of problems in the process. TPC Components AB need their simulations to be optimised against the practical process in order to get results as close as possible to the results from real practice. This thesis is mapping the parameters sensitivity against TPC’s earlier standards to put forward what parameters the result is depending on. The optimization of the parameters is towards measurement of heat and time and practical trial in order to get a scientific ground. The heat transfer for complicated structure needs to be simulated in order to get a reasonable value to work with. Results shows that TPC’s earlier model of simulation have lack of measurement and important parameters are based on assumptions. The work done gave TPC a model closer to the real practice which can both mean faster decisions of how to cast new products and less costly practical trials.
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När larmen tystnar : En fältstudie av ett fartygs brygglarm och dess kausalitet på befälen / Silence of the alarms : A field study of a ships bridge-alarms and their causality on the nautical officersCarenfelt, Carl Sebastian Robert January 2019 (has links)
Syftet med denna studie var att utforska nautiska befäls attityder till larmen de kan ställas inför på sin brygga och den eventuella kausaliteten. Tidigare forskning inom larm och forskning inom optimering av brygglayouter presenterade ett problematiskt fenomen vilken av Papastavrou och Lehto kallas för cry-wolf. Detta fenomen beskriver att operatörer av system med larm, till exempel sjöfartsofficerare, tenderar att ignorera larmen om de utsätts för en hög frekvens av larm, denna höga frekvens kallar Al-Dabbagh och Tongwen för alarm-floods. Denna studie kommer fram till att cry-wolf fenomenet existerar ombord det fartyg studien utfördes på. Datainsamlingen utfördes med den kvalitativa forskningsmetodiken, främst genom semi-strukturerade intervjuer. Dessa intervjuer kompletterades sedan med ostrukturerade observationer vilka utfördes under en nio dagar lång fältstudie. Studiens primärdata analyserades genom innehållsanalyser och detta gjordes ur det hermeneutiska perspektivet. Studien fann att befälen tenderar att ignorera larmen om larmen inte klassas som nödlarm. Vidare presenteras två potentiella lösningar som ämnar ge tillbaka den tyngd larmen borde associeras med. Utöver detta presenteras också en hypotes vilken syftar till att ta reda på om ett givet fartyg påverkas av cry-wolf fenomenet. Denna hypotes måste valideras innan den kan godtas som gångbar för sjöfarten som helhet. / The main purpose of this thesis was to explore nautical officer’s attitudes towards the alarms they may encounter on the bridge and the eventual causality between the officers and their actions concerning the alarms. Earlier research into alarms and research regarding optimization of bridge-layouts presented a problematic theory which Papastavrou and Lehto call cry-wolf. Wherein the operators of systems, or ships, with advanced alarms tend to ignore the alarms if they are subjected to a high frequency of alarms, or alarm-floods as Al-Dabbagh and Tongwen calls it. This study shows that, on board the vessel which the study was conducted, the cry-wolf phenomena exist. The study was conducted on board a Swedish vessel from the hermeneutical perspective. The data collection was done with the qualitative method, primarily through semi-structured interviews and these were then enriched with data from unstructured observations which were made during a nine-day stay aboard said vessel. The collected data has been analysed through content analysis from the hermeneutical perspective and the study reveals that the officers tend to ignore the alarms, unless they are classified as emergency alarms. This study proposes two potential fixes for how to make the alarms less overwhelming and how to give back the importance of the alarms. Furthermore, the study presents a hypothesis which aims to find whether or not a given vessel is subject to the cry-wolf phenomena. This hypothesis needs to be proven in future research before it can be proclaimed as a valid hypothesis.
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Ny teknik för småskalig kraftvärme : - med fokus på Organisk RankineCykel (ORC)Eriksson, Åsa January 2009 (has links)
<p>As a part of the fight against the global warming the energy production needs to be more efficient and redirected towards sustainable options. One alternative is cogeneration, which means that electricity and heat is produced in one plant. The purpose with this survey is to examine if there are any commercial available combined heat and power techniques, based on combustion of solid moist biomass, which are suitable to small-scale applications. The technique must be able to produce between 2 and 10 MW thermal and the heat demand is a Swedish district-heating system. When already published reports had been studied, the Organic Rankine Cycle (ORC) was chosen as the most suitable technique. The possibility of using the ORC to generate electricity from the district-heating return flow was considered simultaneously. The chosen ORC-technique was then evaluated in Excel. The first aspect to be examined was how the performance of a combined heat and power plant was affected by variations in the supply line temperature. It showed that the performance reaches top levels when the temperature is low. The second part contains an optimisation, in a techno-economical perspective, of the ratio between cogeneration and separate heat production for district-heating systems with heat demands below 50 GWh/year. The most profitable combined heat and power plant generates 45 % of the installed power in a 50 GWh system. The profit is, however, too low to justify any construction plans. The conclusion was that there are no economical reasons to choose combined heat and power based on an organic rankine cycle in Sweden today.</p>
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A model to increase profit by optimizing the production process within a cutting station: A case study / En modell för att öka lönsamheten genom optimering av produktionsprocessen i en skärande bearbetningsstation: En fallstudiePetersson, Anton, Hallberg, Peter January 2013 (has links)
Studies have shown that it is necessary for manufacturing industries, in order to stay competitive and increase the profitability, to work with optimizations and continuous improvements of processes. Existing models and philosophies aiming for this, such as PDCA (Plan Do Check Act), IDEA (Investigate Design Execute Adjust), DMAIC (Define Measure Analyze Improve Control), and Lean Production, are either ambiguous or only focusing on one specific area or field. Due to this it is not suitable to apply these singly at a cutting station because root causes to problems can derive from many different factors. The purpose of this thesis has been to develop a model, with the advantage of having a clear and structured approach, and still considering all affecting factors of the cutting station. This leads to a better chance of finding the actual root causes, consequently maximizing the profits gained from the improvement solutions suggested. The model has been applied and tested on a case company and it has been proven to be suitable to use when optimizing a cutting station. Eight alternatives for possible improvements were found, where five of these were estimated to generate more than 800 000 SEK in cost savings each year. For the other three there were no estimations done due to the large extent of the suggestions, but it is believed that these will have an even larger impact on the profitability than the other alternatives. The results found will provide a solid foundation for the company in order to achieve the best possible outcome, when completing the rest of the model. The model has been developed for cutting stations but with small modifications it can be applied on any other production station in a plant. / Studier har visat att det är nödvändigt för tillverkande industrier, för att kunna bibehålla en hög konkurrenskraft och en ökad vinst, att arbeta med optimeringar och ständiga förbättringar av processer. Existerande modeller och filosofier som har detta som mål, såsom PDCA (Plan Do Check Act), IDEA (Investigate Design Execute Adjust), DMAIC (Define Measure Analyze Improve Control), och Lean Production, kan vara otydliga eller fokuserar endast på ett specifikt område eller fält. På grund av detta är det inte passande att applicera dessa individuellt på en skärande bearbetningsstation, då felorsaker kan härstamma från många olika faktorer. Syftet i detta examensarbete har varit att utveckla en modell som har fördelen att ha ett tydligt och strukturerat tillvägagångssätt, men fortfarande ta hänsyn till alla påverkande faktorer i den skärande bearbetningsstationen. Detta medför en större chans till att hitta den verkliga felorsaken, därmed också maximera den tjänade vinsten från förbättringslösningarna som föreslagits. Modellen har blivit applicerad och testad på ett fallföretag samt blivit bevisad att vara passande att använda vid optimeringar av skärande bearbetningsstationer. Åtta alternativ för möjliga förbättringar har hittats, varav fem av dessa var estimerade att generera mer än 800 000 kr i kostnadsbesparingar varje år. På de andra tre alternativen var inga estimeringar utförda på grund av storleken på förslagen, men dessa tros ha en ännu större inverkan på vinsten jämfört med de andra alternativen. Dessa resultat tillhandahåller företaget med en solid grund att stå på, för att kunna uppnå bästa möjliga utfall när resten av modellen slutförs. Modellen har utvecklats för skärande bearbetningsstationer men kan, med mindre modifikationer, även appliceras på vilken produktionsstation som helst på en fabrik.
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Analys av Servera R&S AB:s distribution i Stockholm / Distribution analysis at Servera R&S ABMoback, Daniel, Mroczek, Tobias January 2008 (has links)
Inom grossistbranschen associeras distributionen med svårigheter så som många kunder, små godsvolymer per kund och krav på korta ledtider. Många kunder kräver dessutom leveranser inom vissa tidsfönster. Dessa faktorer ställer höga krav på logistiken och skapar behov om hög leveransservice. Inom transportbranschen råder idag generellt en relativt låg datormognad. Sedan tidigare finns avancerade digitala informationssystem tillgängliga för inköp, ordermottagning och lagerkontroll. Utvecklingen går dock mot att även logistik- och transportavdelningarna i större utsträckning börjar använda sig av mer avancerade transporttekniska hjälpmedel. Exempel på sådana är ruttoptimeringsprogram som kan användas för att beräkna optimala körvägar. Servera R&S är en restauranggrossist som har ett antal lager utspridda i Sverige. Då deras kundkrets i stockholmsområdet under senare år blivit allt större har även antalet lossningsplatser ökat drastiskt. Godset till dessa förses från lager placerade i Norrköping och Västerås. Godset från Norrköping samlas och packas om i en terminal i Årsta innan det transporteras vidare till kunderna i Stockholm. Servera R&S efterfrågade en analys av deras distribution i Stockholm. Detta för att undersöka om nuvarande distributionsstrategier är kostnadseffektiva. Syftet var att finna möjliga förändringar i verksamheten som skulle kunna medföra förbättringar för distributionen till kunder i Stockholm. Målet innefattade att finna förbättringsförslag som skulle innebära ett bättre användande av distributionsnätverkets resurser, minskade transportkostnader och ökad leveransservice. Inledningsvis genomfördes en nulägesanalys för att kartlägga arbetsmetoder och tillvägagångssätt vid distributionen. Utifrån intervjuer och enkätundersökningar skapades sedan en modell av distributionen i vilken det verkliga trafikarbetet efterliknades. Denna användes vid simuleringar i ett ruttoptimeringsprogram med syftet att påvisa förbättringsmöjligheter. Under analysfasen studerades distributionsprocessen och simuleringsresultaten med målet att ta fram förslag på förbättringar och annorlunda tillvägagångssätt vid terminalhantering och transport. Studien visar att det i distributionsprocessen finns stora möjligheter för förbättringar gällande terminalhantering och godstransporter. Ruttoptimeringen påvisar stora besparingsmöjligheter gällande transporttid, antalet körda kilometer och antalet använda fordon i distributionsarbetet. Simuleringsresultaten visar exempelvis en minskning av den totala transportsträckan med upp till 30 procent. Då transportsträckan står i direkt relation till transportkostnaderna skulle en sådan minskning innebära reducerade kostnader för distributionen. / Within the wholesale sector, the distribution is often associated with difficulties, such as many customers and a requirement for short lead times. A lot of customers also demand delivery within certain time windows. These factors all contribute to a high level of strain on the logistics. In general, the amount of computer usage within the transportation industry is relatively low. However, advanced information systems are available for order handling and inventory management, and a lot of software for distribution planning and vehicle routing have surfaced as of recently. These often combine digital maps and optimization algorithms, and can be used for calculating optimized routes within the distribution. Servera R&S is a wholesale company with a number of warehouses in different parts of Sweden. As of lately, their clientele in Stockholm has expanded, and the number of delivery points have increased drastically. The customers in Stockholm are provided with goods from warehouses in Norrköping and Västerås. The goods from Norrköping passes through a transfer terminal in Årsta before it is delivered to the customer in Stockholm. Servera R&S is requesting an analysis of their distribution in Stockholm. They want to determine whether their distribution strategies are economically effective or not. Within this study, we aim to analyze different distribution strategies, which may or may not result in improvements of the efficiency of the distribution process. The purpose is to find solutions that better use the recourses of the distribution network (i.e. vehicles and personnel etc.), increase the level of delivery service and reduce the transportation costs. A survey analysis was carried out to map work methods and procedures within the distribution process. Interviews and surveys were used in the process of creating a basis for the optimization tool. Simulations were performed in an attempt to demonstrate the possibilities for decreasing distribution costs through the use of a vehicle routing program. During the analysis, the distribution process and the results from the simulations were studied with an aim to find possible improvements in the way that goods and information are handled within the warehouses and during the transports. The study shows a lot of possibilities for improvements within the distribution process. The route optimization prove a potential for decreasing costs regarding transportation time, distances and the number of vehicles used within the distribution. For example, the simulations show that the distances can be decreased with as much as 30 percent.
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Ny teknik för småskalig kraftvärme : - med fokus på Organisk RankineCykel (ORC)Eriksson, Åsa January 2009 (has links)
As a part of the fight against the global warming the energy production needs to be more efficient and redirected towards sustainable options. One alternative is cogeneration, which means that electricity and heat is produced in one plant. The purpose with this survey is to examine if there are any commercial available combined heat and power techniques, based on combustion of solid moist biomass, which are suitable to small-scale applications. The technique must be able to produce between 2 and 10 MW thermal and the heat demand is a Swedish district-heating system. When already published reports had been studied, the Organic Rankine Cycle (ORC) was chosen as the most suitable technique. The possibility of using the ORC to generate electricity from the district-heating return flow was considered simultaneously. The chosen ORC-technique was then evaluated in Excel. The first aspect to be examined was how the performance of a combined heat and power plant was affected by variations in the supply line temperature. It showed that the performance reaches top levels when the temperature is low. The second part contains an optimisation, in a techno-economical perspective, of the ratio between cogeneration and separate heat production for district-heating systems with heat demands below 50 GWh/year. The most profitable combined heat and power plant generates 45 % of the installed power in a 50 GWh system. The profit is, however, too low to justify any construction plans. The conclusion was that there are no economical reasons to choose combined heat and power based on an organic rankine cycle in Sweden today.
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