This thesis presents a method for reliability assessment of a power grid with distributed generation providing support to the system. The distributed generation units considered for this assessment are Combined Heat and Power (CHP) units operated by individual customers at their site. CHP refers to the simultaneous generation of useful electric and thermal energy. CHP systems have received more attention recently due to their high overall efficiency combined with decrease in costs and increase in reliability. A composite system adequacy assessment, which includes the two main components of the power grid viz., Generation and Distribution, is done using Monte Carlo simulation. The State Duration Sampling approach is used to obtain the operating history of the generation and the distribution system components from which the reliability indices are calculated. The basic data and the topology used in the analysis are based on the Institution of Electrical and Electronics Engineers - Reliability Test System (IEEE-RTS) and distribution system for bus 2 of the IEEE-Reliability Busbar Test System (IEEE-RBTS). The reliability index Loss of Energy Expectation (LOEE) is used to assess the overall system reliability and the index Average Energy Not Supplied (AENS) is used to assess the individual customer reliability. CHP reliability information was obtained from actual data for systems operating in New England and New York. The significance of the results obtained is discussed.

The liberalization of electricity markets and a growing penetration of renewables is changing operation of electrical grids. The boundary conditions for the operation of conventional power plants are changing and, as such, an improved understanding of the varying loads and prices on the electricity grid is required to assess the performance of emerging combined cycle gas turbine (CCGT) concepts and to further optimize their design for these new markets in the pursuit of increasing their profitability, especially when considering combined heat and power (CHP). To increase the flexibility of CCGT-CHP plants, three new plant layouts have been investigated by integrating different storage concepts and heat pumps in key sections of the traditional plant layout. The present study analyses the influence that market has on determining the optimum CCGT-CHP plant layout that maximizes profits (in terms of plant configuration, sizing and operation strategies) for a given location nearby Turin, Italy, for which hourly electricity and heat prices, as well as meteorological data, have been gathered. A multi-parameter approach for design and operation was followed using KTH’s and EPS’ techno-economic modeling tool DYESOPT. Results are shown by means of a comparative analysis between optimal plants found for each layout and the state-of-the art CCGT-CHP. It is shown that a plant configuration in which a cold storage unit is integrated together with a heat pump at the inlet of the gas turbine unit increases the net present value of the plant by approximately 0.3% when compared against conventional plant layouts. Using the same concept with a heat pump alone can improve lifetime profitability by 1.6%. A layout where district heating supply water is preheated with a combination of a heat pump with hot thermal tank increases plant profitability by up to 0.5%. This work has been performed as part of the PUMP-HEAT project, an EU Horizon 2020 research project in which KTH collaborates with other 13 stakeholders including industry and research institutions. The results will directly influence future work of the project.

No description available.

Micro-cogeneration is one of the technologies promoted as a response to the global call for the reduction of carbon emissions. Due to its recent application in the residential sector, the implications of its usage have not yet been fully explored, while at the same time, the available simulation tools are not designed for conducting research that focuses on the study of this technology. This thesis develops a virtual prototyping environment, using a dynamic multi-physics simulation tool. The model based procedure in its current form focuses on ICE based micro-CHP systems. In the process of developing the models, new approaches on general system, engine, heat exchanger, and dwelling thermal modelling are being introduced to cater for the special nature of the subject. The developed software is a unique modular simulation tool platform linking a number of independent energy generation systems, and presents a new approach in the study and design of the multi node distributed energy system (DES) with the option of further development into a real-time residential energy management system capable of reducing fuel consumption and CO2 emissions in the domestic sector. In the final chapters, the developed software is used to simulate various internal combustion engine based micro-CHP configurations in order to conclude on the system design characteristics, as well as the conditions, necessary to achieve a high technical, economic and environmental performance in the UK residential sector with the purpose of making micro- CHP a viable alternative to the conventional means of heat & power supply.

Der integrierte Gas-Dampf (GiD-) Prozess mit Wasserrückgewinnung ist ein flexibler Kraft-Wärme-Kopplungsprozess, der die gleichzeitige Bereitstellung von Strom und Wärme teilweise entkoppeln kann. Der effiziente und sparsame Einsatz von fossilen Brennstoffen ist aus ökonomischer wie auch ökologischer Sicht geboten. Die Kraft-Wärme-Kopplung (KWK), die gleichzeitige Erzeugung von Strom und Wärme, ist eine Möglichkeit dafür. Allerdings erfordert die KWK auch eine gleichzeitige Abnahme von Strom und Wärme beziehungsweise deren Speicherung. Sowohl Strom als auch Prozessdampf lassen sich nur aufwendig und damit relativ teuer speichern, weshalb Alternativen gefragt sind. Der GiD-Prozess besteht aus einer Gasturbine mit nachgeschaltetem Abhitzedampfkessel. Die Gasturbine verfügt als Besonderheit über eine Dampfinjektion, die vor, nach oder direkt in die Brennkammer erfolgen kann. Der Abhitzekessel hat zusätzliche Wärmeübertragerflächen um das Abgas bis unter den Taupunkt abzukühlen. Somit kann ein Teil des injizierten Dampfes aus dem Abgas zurückgewonnen und wiederverwendet werden. Der in die Gasturbine injizierte Dampf führt dieser weitere Energie zu. Diese kann entweder zur Leistungssteigerung der Anlage oder zur Reduzierung des fossilen Brennstoffbedarfes genutzt werden. Die erste Option der Leistungssteigerung ist auch als Cheng-Prozess bekannt. Diese Arbeit widmet sich der weniger untersuchten zweiten Möglichkeit der Brennstoffreduzierung. Beim Vergleich des GiD-Prozesses mit verschiedenen anderen Kraftwerks-Prozessen zeigt sich, dass dieser besonders gut für industrielle Anlagen mit Prozessdampfbedarf und einer elektrischen Leistung kleiner 20 MW el geeignet ist. Im Rahmen dieser Arbeit wurde der GiD-Prozess mittels einer Versuchsanlage auf Basis einer Industriegasturbine mit 650 kW el untersucht. Die Arbeit dokumentiert verschiedene Versuchsfahrten und Untersuchungen an dieser Anlage. Die Injektion von Dampf reduziert die Schadstoffemissionen in den zulässigen Bereich und kann sehr flexibel zu einer Steigerung des Anlagenwirkungsgrades von bis zu zwei Prozent führen. Dabei wird der Dampf sehr gleichmäßig in die Versuchsanlage eingebracht, so dass keine signifikanten Änderungen der Abgastemperaturverteilung erkennbar sind. Die Überhitzung des Dampfes kann zu einer weiteren Steigerung des Anlagenwirkungsgrades führen. Die Rückgewinnung des eingebrachten Dampfes ist mit den entsprechenden Wärmeübertragern möglich. Das zurückgewonnene Wasser ist durch die Stickoxide des Abgases verunreinigt und muss entsprechend aufbereitet werden.

Le concentrateur à réflecteur linéaire de Fresnel (LFR) est une technologie solaire thermodynamique en plein essor : petites applications industrielles (chaleur, froid, électricité) à centrales électriques (10-100 MWel). Ce travail de thèse établit un modèle global du procédé solaire, en régime permanent, pour un prédimensionnement du système. Le modèle comprend trois parties chaînées : (i) les transferts radiatifs dans le concentrateur optique, modélisés précisément par une méthode de Monte Carlo (environnement EDStar) ; (ii) les transferts thermiques dans le récepteur, évalués analytiquement (puissances, températures) ; (iii) le cycle thermodynamique, avec Thermoptim. L’application étudiée couple un concentrateur LFR à un moteur Ericsson. L’air est fluide caloporteur et de travail. Un prototype est en construction. L’hybridation et le stockage thermique sont des options clés. Un modèle systémique permettrait d’optimiser l’opération du procédé, en étudiant son comportement dynamique. / Linear Fresnel Reflector (LFR) is a promising Concentrating Solar Power technology. Research is booming and industrial applications are emerging. Applications range from small production units (heat, cold, electricity) to utility scale power plants (several tenths of MW). This PhD work establishes a global model of the solar process, in order to improve our knowledge of the system’s performances. It is a static model suited for a pre-design of the system. The model is chaining three parts. Radiative heat transfer in the optical concentrator is modelled by Monte Carlo statistical Method. The algorithm enables a detailed study of any geometrical configuration, especially through absorbed power flux maps on the receiver. The simulation tool is using the environment of development EDStar. The thermal model calculates analytically the useful thermal power, losses and temperature profiles along the receiver (glass cover, fluid, pipe...). The thermodynamic cycle is simulated analytically using the software Thermoptim. The studied application uses air as heat transfer and working fluid. Air directly feeds an Ericsson engine. The engine developed by LaTEP laboratory is promising for small scale cogeneration (1 to several tenths of kWel). The prototype Linear Fresnel Reflector built in Ecole des Mines d’Albi will enable experimental study of a solar process coupling an LFR concentrator and an Ericsson engine. The technology under study can feed a power plant or a cogeneration system in the industry, producing electricity and heat at 100 to 250°C. Hybridisation with an other energy source (biomass, gas...) and thermal storage (molten salt?) are key features to investigate. To optimise the operating strategy of the process, dynamic behaviour must be studied: a systemic or agent based model is a very relevant approach.

This project presents a feasibility study and an investigation of the potential for low temperature district heating system in Västerås. The investigation treats integrations possibilities for 4GDH (4th Generation District Heating) in Kungsängens area in Västerås, which is undergoing a large-scale building-up and construction.  The study is conducted for the company Mälarenergi AB. The advantages of 4GDH technology are identified and analyzed, where energy effectiveness and economic benefits aspects were concluded. Problems with existing technology and higher cooling demand expectations drive 4GDH to be an interesting and necessary technology in the future. Four Different integration solutions between old and new networks are presented, analyzed and discussed. Quantitative analysis conducted where initial cost for the four technical solutions were estimated and compared. The results show that low temperature district heating could lead to reduction in the initial cost for the network by using PEX instead of steel as pipe material. The results show also that one solution using heat exchanger as exchange stations has the lowest cost between the four solutions. The results show that the cost for the retention flow that is linked with 4GDH stands for 20%-30% of the total cost. The importance of the retention flow pipe is investigated using two physical models in OpenModelica and Excel, where simulations were conducted. It is concluded that it is possible to provide Kungsängen area with low temperature district heating without having the retention flow pipe. Three parameters were identified to be critical which are, geographical placement of the consumers, pattern variation for the heat demand and heat systems installed inside consumer’s buildings. The results show also that it might be critical to have a variate and optimized supply temperature for the area, depending on the demand. The simulations of a fictive area that could present a future heat demand for Kungsängen area shows that a temperature of 55°C is satisfying during winter season where the demand is high and a temperature between 60-65°C must be available during spring/autumn seasons and specially during summer. The variation depends directly on the temperature drop through the supply pipes to the consumers. The temperature drop is directly linked with water velocity inside the pipes. The losses increase during summer nights when the heat demand is low which lead to low water velocities.

Made available in DSpace on 2017-07-10T19:25:07Z (GMT). No. of bitstreams: 1 Florian Schirmer.pdf: 2016231 bytes, checksum: 57aa2561433d1c4c0448c03930721ca7 (MD5) Previous issue date: 2006-06-27 / This work has an objective to study and to compare energetic and exergetic indicatives of two sugar and alcohol sector industry. The study was realized in 2005 harvest time at both industries. It was opted in doing the experiment collecting datas from individual boilers in each industry, quantity of ground cane, properties of cane and bagasse, quantity of energy involved in process per sectors, commercialized energy with the concession of each region and characteristics of each equipment involved in the process. The data were collected from respective department data-bank and through interviews with the responsibles for each sector, being the work based on studies done by diary and monthly average from collected data. The results pointed that each analyzed industry has different indicators for each studied data. The study states that both factories need more efficient equipments. And exergetic indicators presented results next to the studies done to Vale do Rosário Factory and mentioned on this work. / Este trabalho teve como objetivo estudar e comparar indicativos energéticos e exergéticos de duas indústrias do setor sucroalcooleiro. O estudo foi realizado no período de safra 2005 em ambas as indústrias. Optou-se em se fazer o experimento utilizando-se dados das caldeiras individualmente em cada indústria, quantidade de cana moída, propriedades da cana e do bagaço, quantidade de energia envolvida no processo por setores, energia comercializada com a concessionária de cada região e características de cada equipamento envolvido no processo. Os dados foram colhidos dos bancos de dados dos respectivos departamentos e por meio de entrevistas com os responsáveis de cada setor, sendo o trabalho baseado em estudos feitos pelas médias diárias e mensais dos dados coletados. Os resultados apontaram que cada indústria analisada tem indicadores diferentes para cada dado estudado. O estudo comprova que ambas as usinas necessitam de equipamentos mais eficientes. Já os indicadores exergéticos apresentaram resultados muito próximos aos do estudo feito para a Usina Vale do Rosário e mencionados neste trabalho.

Made available in DSpace on 2017-05-12T14:48:29Z (GMT). No. of bitstreams: 1 Florian Schirmer.pdf: 2016231 bytes, checksum: 57aa2561433d1c4c0448c03930721ca7 (MD5) Previous issue date: 2006-06-27 / This work has an objective to study and to compare energetic and exergetic indicatives of two sugar and alcohol sector industry. The study was realized in 2005 harvest time at both industries. It was opted in doing the experiment collecting datas from individual boilers in each industry, quantity of ground cane, properties of cane and bagasse, quantity of energy involved in process per sectors, commercialized energy with the concession of each region and characteristics of each equipment involved in the process. The data were collected from respective department data-bank and through interviews with the responsibles for each sector, being the work based on studies done by diary and monthly average from collected data. The results pointed that each analyzed industry has different indicators for each studied data. The study states that both factories need more efficient equipments. And exergetic indicators presented results next to the studies done to Vale do Rosário Factory and mentioned on this work. / Este trabalho teve como objetivo estudar e comparar indicativos energéticos e exergéticos de duas indústrias do setor sucroalcooleiro. O estudo foi realizado no período de safra 2005 em ambas as indústrias. Optou-se em se fazer o experimento utilizando-se dados das caldeiras individualmente em cada indústria, quantidade de cana moída, propriedades da cana e do bagaço, quantidade de energia envolvida no processo por setores, energia comercializada com a concessionária de cada região e características de cada equipamento envolvido no processo. Os dados foram colhidos dos bancos de dados dos respectivos departamentos e por meio de entrevistas com os responsáveis de cada setor, sendo o trabalho baseado em estudos feitos pelas médias diárias e mensais dos dados coletados. Os resultados apontaram que cada indústria analisada tem indicadores diferentes para cada dado estudado. O estudo comprova que ambas as usinas necessitam de equipamentos mais eficientes. Já os indicadores exergéticos apresentaram resultados muito próximos aos do estudo feito para a Usina Vale do Rosário e mencionados neste trabalho.

Fossil fuel depletion, economic development, urban expansion and climate change present tough challenges to municipal- and regional-scale energy systems. Regional energy system planning, including waste treatment, renewable energy supply, energy efficiency, and climate change, are considered essential to meet these challenges and move toward a sustainable society. This thesis includes studies on energy system from municipal waste, potential for a fossil fuel-independent regional energy system with increased renewable energy products using waste as one of energy sources, and the performance of biomass-fired combined heat and power (CHP) plants. A top-down method is adopted to organize the studies, from national waste-to-energy (WtE) scenarios to individual energy plants. The first study considers the overall potential contribution of WtE to energy supply and greenhouse gas (GHG) emissions mitigation in Sweden until 2050 under several different scenarios. Depending on WtE scenario considered, the study shows that WtE can supply energy between 38 and 186 TWh and mitigate between CO2 of 1 and 12 Mt per year by 2050 based on the baseline of year 2010. At a regional level, static and dynamic optimization models with a focus on WtE are developed for two regions in Sweden and Finland. The former is used to investigate the possibilities of optimal positioning of new energy plants, retrofitting existing energy plants and planting energy crops. The latter case study is on regional heat and power production using biogas generated from agricultural and livestock wastes. Centralized biogas production units perform better than distributed production regarding energy and carbon balance though the net energy output is negligible. However, a significant GHG emission can be reduced compared to the present status. Retrofitting existing conventional CHP plants is another option for improving regional energy system. The study shows that integrating heat-demanded processes such as drying, bioethanol and pellet production with existing CHP plants can improve overall energy efficiency and power output, increase annual operation time and reduce production cost as well as mitigate GHG emissions.  It is recommended that building new WtE/energy plants at optimum sites, upgrading the existing energy plants, expanding the agricultural/forestry waste/residues output (biomass) and planting more energy crops shall be taken into considerations for the future regional energy systems. / Utarmning av fossila bränslekällor, ekonomisk utveckling, städernas utbredning och klimatförändring är svåra utmaningar för kommunala- och regionala energisystem. Planering av det regionala energisystemet, inklusive avfallshantering, förnyelsebara energikällor, energieffektivisering och hänsyn till klimatförändringar, anses avgörande för att möta dessa utmaningar och gå mot ett hållbart samhälle. Denna avhandling innehåller studier av energisystem centrerad kring hushållsavfall, potentialet för fossilbränslefria regionala energisystem som utnyttjar ökad andel förnyelsebara energiprodukter med avfall som en energikälla och prestandautvärdering av ett biomassa-eldat kraftvärmeverk. Studierna har organiserats efter storlek på system, från nationella avfall-till-energi scenarier till enskilda kraftverk.   Den första studien behandlar övergripande möjligheten att genom avfall-till-energi bidra till energiförsörjningen och begränsa utsläppet av växthusgaser i Sverige till 2050 under flera olika scenarier. Beroendet på avfall-till-energiscenario visar studien att genom att utnyttja avfall kan mellan 38 och 186 TWh energi levereras och dessutom kan koldioxidutsläppen reduceras med 1-12 miljoner ton till år 2050 med 2010 som basår.   På den regionala nivån, statiska och dynamiska optimeringsmodeller, med fokus på avfall-till-energi, är utvecklats för två regioner, en i Sverige och en i Finland. Det första modellen används för hitta den optimala placeringen av nya energianläggningar, anpassning av befintliga anläggningar och placering av odlingar av energigrödor. Den senare ingår i en fallstudie av den regionala kraft- och värmeproduktionen genom utnyttjande av biogas producerad från jordbruksavfall och djurgödsel. Centraliserade biogasanläggningar presterar bättre än decentraliserad anläggningar när det gäller energi – och kolbalanser även om i båda fallen så är skillnaden mellan konsumerad mängd bränsle, värme och el och producerad värme och el försumbar. Däremot kan en betydande mängd av växthusgasutsläppet i båda fallen undvikas jämfört med nuläget.   Anpassning av befintliga konventionella kraftvärmeverk är ett annat alternativ för att förbättra det regionala energisystemet. Studien visar att genom att integrera värmekrävande processer såsom torkning, bioetanol- och pelletsproduktion med befintliga kraftvärmeverk kan den totala energieffektiviten och uteffekten förbättras, öka den årliga drifftiden och minska produktionskostnaderna och utsläppen av växthusgaser.   Rekommendationen är att för de framtida regionala energisystemen överväga att bygga nya avfall-till-energianläggningar med optimal placering, uppgradera befintliga energianläggningar utöka insamlandet av avfall/restprodukter från jord- och skogbruk och plantera mer energigrödor.