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Analysis of a Clean Energy Hub Interfaced with a Fleet of Plug-in Fuel Cell VehiclesSyed, Faraz January 2011 (has links)
The ‘hydrogen economy’ represents an energy system in which hydrogen and electricity are the dominant energy carriers for use in transportation applications. The ‘hydrogen economy’ minimizes the use of fossil fuels in order to lower the environmental impact of energy use associated with urban air pollution and climate change. An integrated energy system is required to deal with diverse and distributed energy generation technologies such a wind and solar which require energy storage to level energy availability and demand. A distributed ‘energy hub’ is considered a viable concept in envisioning the structure of an integrated energy system. An energy hub is a system which consists of energy input/output, conversion and storage technologies for multiple energy carriers, and would provide an interface between energy producers, consumers, and the transportation infrastructure. Considered in a decentralized network, these hubs would form the nodes of an integrated energy system or network.
In this work, a model of a clean energy hub comprising of wind turbines, electrolyzers, hydrogen storage, a commercial building, and a fleet of plug-in fuel cell vehicles (PFCVs) was developed in MATLAB, with electricity and hydrogen used as the energy carriers. This model represents a hypothetical commercial facility which is powered by a renewable energy source and utilizes a zero-emissions fleet of light duty vehicles. The models developed herein capture the energy and cost interactions between the various energy components, and also calculate the CO2 emissions avoided through the implementation of hydrogen economy principles. Wherever possible, similar models were used to inform the development of the clean energy hub model. The purpose of the modelling was to investigate the interactions between a single energy hub and novel components such as a plug-in fuel cell vehicle fleet (PFCV). The final model reports four key results: price of hub electricity, price of hub hydrogen, total annual costs and CO2 emissions avoided. Three scenarios were analysed: minimizing price of hub electricity, minimizing total annual costs, and maximizing the CO2 emissions avoided.
Since the clean energy hub could feasibly represent both a facility located within an urban area as well as a remote facility, two separate analyses were also conducted: an on-grid analysis (if the energy hub is close to transmission lines), and an off-grid analysis (representing the remote scenarios).
The connection of the energy hub to the broader electricity grid was the most significant factor affecting the results collected. Grid electricity was found to be generally cheaper than electricity produced by wind turbines, and scenarios for minimizing costs heavily favoured the use grid electricity. However, wind turbines were found to avoid CO2 emissions over the use of grid electricity, and scenarios for maximizing emissions avoided heavily favoured wind turbine electricity. In one case, removing the grid connection resulted in the price of electricity from the energy hub increasing from $82/MWh to $300/MWh.
The mean travel distance of the fleet was another important factor affecting the cost modelling of the energy hub. The hub’s performance was simulated over a range of mean travel distances (20km to 100km), and the results varied greatly within the range. This is because the mean travel distance directly affects the quantities of electricity and hydrogen consumed by the fleet, a large consumer of energy within the hub. Other factors, such as the output of the wind turbines, or the consumption of the commercial building, are largely fixed. A key sensitivity was discovered within this range; the results were ‘better’ (lower costs and higher emissions avoided) when the mean travel distance exceeded the electric travel range of the fleet. This effect was more noticeable in the on-grid analysis. This sensitivity is due to the underutilization of the hydrogen systems within the hub at lower mean travel distances. It was found that the greater the mean travel distance, the greater the utilization of the electrolyzers and storage tanks lowering the associated per km capital cost of these components. At lower mean travel distances the utilization of the electrolyzers ranged from 25% to 30%, whereas at higher mean travel distances it ranged from 97% to 99%. At higher utilization factors the price of hydrogen is reduced, since the cost recovery is spread over a larger quantity of hydrogen.
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The Ambitious City: Stimulating Change through the Urban ArtifactFearman, Carolyn January 2011 (has links)
In the late twentieth century, global economic forces changed the face of many North American cities. Cities which were built upon industry, that had provided both job certainty and economic vitality, faced questions of survival in response to shrinking population and urban blight. Unprepared for these drastic changes and unable to address them survival gave way to resignation.
Buffalo, New York is an example of a once successful and vital city that continues to experience de-population due to the collapse of its industries. The collapse not only created economic repercussions but also effected the city’s built environment. Many of the Buffalo’s urban monuments, testaments to the ambition of the city, now sit empty; as do the working class neighbourhoods that surround them.
The Thesis examines the role which architecture can play in understanding, strategizing and re-envisioning the life of deteriorating cities. Focusing on the City of Buffalo, the design centers on the New York Central Terminal. It proposes a radical repurposing of the Terminal to create a new urban hub which will spur the re-building of the city’s urban fabric.
The design outlines a staged 25 year strategy for the de-construction of sparse areas and the strengthening of critical urban networks, thus creating a strong framework upon which a new physical fabric for the city can build and develop overtime. The Terminal, once a significant rail hub is re-envisioned as a revitalized hub for the new city. A key connective point within this urban framework, it encapsulates a variety of program moved from the surrounding neighbourhood to the site. The Terminal will act as an architectural catalyst for change, working within the larger urban strategy to spur a natural re-growth and densification of the city.
The thesis presents the radical re-thinking of the architect’s role in the twenty-first century. As current economies and industries face change the urban climate is adapting from one of constant growth to one of strategic re-use. Skeletons of once successful cities lay across the North American landscape. Their urban artifacts: the grain mill, steel manufacturing plant and rail yards, which once supported whole cities as both providers of employment and definers of cultural identity, now stand as empty reminders of a prosperous past. The Thesis shows how these buildings , like the New York Central Terminal can be given a renewed cultural significance and powerful roles within the revived urban life of their cities.
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Patterns of Freight Flow and Design of a Less-than-Truckload Distribution NetworkDave, Devang Bhalchandra 12 April 2004 (has links)
A less-than-truckload (LTL) carrier typically delivers shipments less than 10,000 pounds (classified as LTL shipment). The size of the shipment in LTL networks provides ample opportunities for consolidation. LTL carriers have focused on hub-and-spoke based consolidation to realize economies of scale. Generally, hub-and-spoke systems work as follows: the shipment is picked up from the shipper and brought to an origin terminal, which is the entry point into the hub-and-spoke system. From the terminal, the freight is sent to the first hub, where it is sorted and consolidated with other shipments, and then sent on to a second hub. It is finally sent from the second hub to the destination terminal, which is the exit point of the hub-and-spoke system.
However, the flow of shipments is often more complicated in practice. In an attempt to reduce sorting costs, load planners sometimes take this hub-and-spoke infrastructure and modify it considerably to maximize their truck utilization while satisfying service constraints. Decisions made by a load planner may have a cascading effect on load building throughout the network. As a result, decentralized load planning may result in expensive global solutions.
Academic as well as industrial researchers have adapted a hierarchical approach to design the hub-and-spoke networks: generate the hub-and-spoke network, route shipments within this hub-and-spoke network (generate a load plan) and finally, balance the empty trailers. We present mathematical models and heuristics for each of the steps involved in the design of the hub-and-spoke network. The heuristics are implemented in a user-friendly graphical tool that can help understand patterns of freight flow and provide insights into the design of the hub-and-spoke network. We also solved the load planning sub-problem in a parallel computation environment to achieve significant speed-ups. Because of the quick solution times, the tool lays the foundation to address pressing further research questions such as deciding location and number of hubs.
We have used data provided by Roadway Parcel Services, Inc. (RPS), now FedEx Ground, as a case-study for the heuristics. Our solutions rival the existing industry solutions which have been a product of expensive commercial software and knowledge acquired by the network designers in the industry.
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The Fleet-Sizing-and-Allocation Problem: Models and Solution ApproachesEl-Ashry, Moustafa 26 November 2007 (has links) (PDF)
Transportation is one of the most vital services in modern society. It makes most of the other functions of society possible. Real transportation systems are so large and complex that in order to build the science of transportation systems it will be necessary to work in many areas, such as: Modeling, Optimization and Simulation. We are interested in solutions for the so-called fleet-sizing-and-allocation problem (FSAP). Fleet sizing and allocation problems are one of the most interesting and hard to solve logistic problems. A fleet sizing and allocation problem consists of two interdependent parts. The fleet sizing problem is to determine a number of transportation units that optimally balances service requirements against the cost of purchasing and maintaining the transportation units. The allocation problem is dealing with the repositioning of transportation units to serve future transportation demand.
To make the fleet sizing and allocation problem a little bit more tractable we concentrate on logistic systems with a special hub-and-spoke structure. We start with a very simple fleet sizing of one-to-one case. This case will cause us to focus attention on several key issues in fleet sizing. Afterwards, the generalization of the one-to-one system is the one-to-many system. As a simple example can serve the continuous time situation where a single origin delivers items to many destinations. For the case that items are produced in a deterministic production cycle and transportation times are stochastic. We also studied a hub-and-spoke problem with continuous time and stochastic demand. To solve this problem, based on Marginal Analysis, we applied queueing theory methods.
The investigation of the fleet-sizing-and-allocation problem for hub-and-spoke systems is started for a single-period, deterministic-demand model. In that the model hub has to decide how to use a given number of TU’s to satisfy a known (deterministic) demand in the spokes. We consider two cases:
1. Renting of additional TU’s from outside the system is not possible, 2. Renting of additional TU’s from outside the system is possible. For each case, based on Marginal Analysis, we developed a simple algorithm, which gives us the cost-minimal allocation. Since the multi-period, deterministic demand problem is NP-hard we suggest to use Genetic Algorithms. Some building elements for these are described.
For the most general situation we also suggest to use simulation optimization. To realize the simulation optimization approach we could use the software tool “Calculation Assessment Optimization System” (CAOS). The idea of CAOS is to provide a software system, which separates the optimization process from the optimization problem. To solve an optimization problem the user of CAOS has to build up a model of the system to which the problem is related. Furthermore he has to define the decision parameters and their domain. Finally, we used CAOS for two classes of hub-and-spoke system: 1. A single hub with four spokes, 2. A single hub with fifty spokes. We applied four optimizers – a Genetic Algorithm, Tabu Search, Hybrid Parallel and Hybrid Serial with two distributions (Normal Distribution and Exponential Distribution) for a customer interarrival times and their demand.
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Enabling Utility-Scale Electrical Energy Storage through Underground Hydrogen-Natural Gas Co-StoragePeng, Dan 11 September 2013 (has links)
Energy storage technology is needed for the storage of surplus baseload generation and the storage of intermittent wind power, because it can increase the flexibility of power grid operations. Underground storage of hydrogen with natural gas (UHNG) is proposed as a new energy storage technology, to be considered for utility-scale energy storage applications. UHNG is a composite technology: using electrolyzers to convert electrical energy to chemical energy in the form of hydrogen. The latter is then injected along with natural gas into existing gas distribution and storage facilities. The energy stored as hydrogen is recovered as needed; as hydrogen for industrial and transportation applications, as electricity to serve power demand, or as hydrogen-enriched natural gas to serve gas demand. The storage of electrical energy in gaseous form is also termed “Power to Gas”. Such large scale electrical energy storage is desirable to baseload generators operators, renewable energy-based generator operators, independent system operators, and natural gas distribution utilities. Due to the low density of hydrogen, the hydrogen-natural gas mixture thus formed has lower volumetric energy content than conventional natural gas. But, compared to the combustion of conventional natural gas, to provide the same amount of energy, the hydrogen-enriched mixture emits less carbon dioxide.
This thesis investigates the dynamic behaviour, financial and environmental performance of UHNG through scenario-based simulation. A proposed energy hub embodying the UHNG principle, located in Southwestern Ontario, is modeled in the MATLAB/Simulink environment. Then, the performance of UHNG for four different scenarios are assessed: injection of hydrogen for long term energy storage, surplus baseload generation load shifting, wind power integration and supplying large hydrogen demand. For each scenario, the configuration of the energy hub, its scale of operation and operating strategy are selected to match the application involved. All four scenarios are compared to the base case scenario, which simulates the operations of a conventional underground gas storage facility.
For all scenarios in which hydrogen production and storage is not prioritized, the concentration of hydrogen in the storage reservoir is shown to remain lower than 7% for the first three years of operation. The simulation results also suggest that, of the five scenarios, hydrogen injection followed by recovery of hydrogen-enriched natural gas is the most likely energy recovery pathway in the near future. For this particular scenario, it was also found that it is not profitable to sell the hydrogen-enriched natural gas at the same price as regular natural gas. For the range of scenarios evaluated, a list of benchmark parameters has been established for the UHNG technology. With a roundtrip efficiency of 39%, rated capacity ranging from 25,000 MWh to 582,000 MWh and rated power from 1 to 100 MW, UHNG is an energy storage technology suitable for large storage capacity, low to medium power rating storage applications.
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Controlling over-actuated road vehicles during failure conditionsWanner, Daniel January 2015 (has links)
The aim of electrification of chassis and driveline systems in road vehicles is to reduce the global emissions and their impact on the environment. The electrification of such systems in vehicles is enabling a whole new set of functionalities improving safety, handling and comfort for the user. This trend is leading to an increased number of elements in road vehicles such as additional sensors, actuators and software codes. As a result, the complexity of vehicle components and subsystems is rising and has to be handled during operation. Hence, the probability of potential faults that can lead to component or subsystem failures deteriorating the dynamic behaviour of road vehicles is becoming higher. Mechanical, electric, electronic or software faults can cause these failures independently or by mutually influencing each other, thereby leading to potentially critical traffic situations or even accidents. There is a need to analyse faults regarding their influence on the dynamic behaviour of road vehicles and to investigate their effect on the driver-vehicle interaction and to find new control strategies for fault handling. A structured method for the classification of faults regarding their influence on the longitudinal, lateral and yaw motion of a road vehicle is proposed. To evaluate this method, a broad failure mode and effect analysis was performed to identify and model relevant faults that have an effect on the vehicle dynamic behaviour. This fault classification method identifies the level of controllability, i.e. how easy or difficult it is for the driver and the vehicle control system to correct the disturbance on the vehicle behaviour caused by the fault. Fault-tolerant control strategies are suggested which can handle faults with a critical controllability level in order to maintain the directional stability of the vehicle. Based on the principle of control allocation, three fault-tolerant control strategies are proposed and have been evaluated in an electric vehicle with typical faults. It is shown that the control allocation strategies give a less critical trajectory deviation compared to an uncontrolled vehicle and a regular electronic stability control algorithm. An experimental validation confirmed the potential of this type of fault handling using one of the proposed control allocation strategies. Driver-vehicle interaction has been experimentally analysed during various failure conditions with typical faults of an electric driveline both at urban and motorway speeds. The driver reactions to the failure conditions were analysed and the extent to which the drivers could handle a fault were investigated. The drivers as such proved to be capable controllers by compensating for the occurring failures in time when they were prepared for the eventuality of a failure. Based on the experimental data, a failure-sensitive driver model has been developed and evaluated for different failure conditions. The suggested fault classification method was further verified with the conducted experimental studies. The interaction between drivers and a fault-tolerant control system with the occurrence of a fault that affects the vehicle dynamic stability was investigated further. The control allocation strategy has a positive influence on maintaining the intended path and the vehicle stability, and supports the driver by reducing the necessary corrective steering effort. This fault-tolerant control strategy has shown promising results and its potential for improving traffic safety. / <p>QC 20150520</p>
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Analysis of a Clean Energy Hub Interfaced with a Fleet of Plug-in Fuel Cell VehiclesSyed, Faraz January 2011 (has links)
The ‘hydrogen economy’ represents an energy system in which hydrogen and electricity are the dominant energy carriers for use in transportation applications. The ‘hydrogen economy’ minimizes the use of fossil fuels in order to lower the environmental impact of energy use associated with urban air pollution and climate change. An integrated energy system is required to deal with diverse and distributed energy generation technologies such a wind and solar which require energy storage to level energy availability and demand. A distributed ‘energy hub’ is considered a viable concept in envisioning the structure of an integrated energy system. An energy hub is a system which consists of energy input/output, conversion and storage technologies for multiple energy carriers, and would provide an interface between energy producers, consumers, and the transportation infrastructure. Considered in a decentralized network, these hubs would form the nodes of an integrated energy system or network.
In this work, a model of a clean energy hub comprising of wind turbines, electrolyzers, hydrogen storage, a commercial building, and a fleet of plug-in fuel cell vehicles (PFCVs) was developed in MATLAB, with electricity and hydrogen used as the energy carriers. This model represents a hypothetical commercial facility which is powered by a renewable energy source and utilizes a zero-emissions fleet of light duty vehicles. The models developed herein capture the energy and cost interactions between the various energy components, and also calculate the CO2 emissions avoided through the implementation of hydrogen economy principles. Wherever possible, similar models were used to inform the development of the clean energy hub model. The purpose of the modelling was to investigate the interactions between a single energy hub and novel components such as a plug-in fuel cell vehicle fleet (PFCV). The final model reports four key results: price of hub electricity, price of hub hydrogen, total annual costs and CO2 emissions avoided. Three scenarios were analysed: minimizing price of hub electricity, minimizing total annual costs, and maximizing the CO2 emissions avoided.
Since the clean energy hub could feasibly represent both a facility located within an urban area as well as a remote facility, two separate analyses were also conducted: an on-grid analysis (if the energy hub is close to transmission lines), and an off-grid analysis (representing the remote scenarios).
The connection of the energy hub to the broader electricity grid was the most significant factor affecting the results collected. Grid electricity was found to be generally cheaper than electricity produced by wind turbines, and scenarios for minimizing costs heavily favoured the use grid electricity. However, wind turbines were found to avoid CO2 emissions over the use of grid electricity, and scenarios for maximizing emissions avoided heavily favoured wind turbine electricity. In one case, removing the grid connection resulted in the price of electricity from the energy hub increasing from $82/MWh to $300/MWh.
The mean travel distance of the fleet was another important factor affecting the cost modelling of the energy hub. The hub’s performance was simulated over a range of mean travel distances (20km to 100km), and the results varied greatly within the range. This is because the mean travel distance directly affects the quantities of electricity and hydrogen consumed by the fleet, a large consumer of energy within the hub. Other factors, such as the output of the wind turbines, or the consumption of the commercial building, are largely fixed. A key sensitivity was discovered within this range; the results were ‘better’ (lower costs and higher emissions avoided) when the mean travel distance exceeded the electric travel range of the fleet. This effect was more noticeable in the on-grid analysis. This sensitivity is due to the underutilization of the hydrogen systems within the hub at lower mean travel distances. It was found that the greater the mean travel distance, the greater the utilization of the electrolyzers and storage tanks lowering the associated per km capital cost of these components. At lower mean travel distances the utilization of the electrolyzers ranged from 25% to 30%, whereas at higher mean travel distances it ranged from 97% to 99%. At higher utilization factors the price of hydrogen is reduced, since the cost recovery is spread over a larger quantity of hydrogen.
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The Ambitious City: Stimulating Change through the Urban ArtifactFearman, Carolyn January 2011 (has links)
In the late twentieth century, global economic forces changed the face of many North American cities. Cities which were built upon industry, that had provided both job certainty and economic vitality, faced questions of survival in response to shrinking population and urban blight. Unprepared for these drastic changes and unable to address them survival gave way to resignation.
Buffalo, New York is an example of a once successful and vital city that continues to experience de-population due to the collapse of its industries. The collapse not only created economic repercussions but also effected the city’s built environment. Many of the Buffalo’s urban monuments, testaments to the ambition of the city, now sit empty; as do the working class neighbourhoods that surround them.
The Thesis examines the role which architecture can play in understanding, strategizing and re-envisioning the life of deteriorating cities. Focusing on the City of Buffalo, the design centers on the New York Central Terminal. It proposes a radical repurposing of the Terminal to create a new urban hub which will spur the re-building of the city’s urban fabric.
The design outlines a staged 25 year strategy for the de-construction of sparse areas and the strengthening of critical urban networks, thus creating a strong framework upon which a new physical fabric for the city can build and develop overtime. The Terminal, once a significant rail hub is re-envisioned as a revitalized hub for the new city. A key connective point within this urban framework, it encapsulates a variety of program moved from the surrounding neighbourhood to the site. The Terminal will act as an architectural catalyst for change, working within the larger urban strategy to spur a natural re-growth and densification of the city.
The thesis presents the radical re-thinking of the architect’s role in the twenty-first century. As current economies and industries face change the urban climate is adapting from one of constant growth to one of strategic re-use. Skeletons of once successful cities lay across the North American landscape. Their urban artifacts: the grain mill, steel manufacturing plant and rail yards, which once supported whole cities as both providers of employment and definers of cultural identity, now stand as empty reminders of a prosperous past. The Thesis shows how these buildings , like the New York Central Terminal can be given a renewed cultural significance and powerful roles within the revived urban life of their cities.
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Gestaltung von kooperativen Logistiknetzwerken : Bewertung unter ökonomischen und ökologischen Aspekten /Rösler, Oliver M. January 2003 (has links) (PDF)
Univ., Diss.--Paderborn, 2002.
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Um portal para o Pacífico : o eixo interoceânico central e a inserção econômica brasileiraNumair, Eliane January 2009 (has links)
A presente dissertação busca analisar as motivações que levam o Estado brasileiro a atuar na arena internacional, visando assegurar a competitividade das empresas brasileiras no mercado externo, especificamente a participar politicamente e investir recursos na Iniciativa para a Integração da Infraestrutura Regional Sul- Americana, com opção pelo recorte na integração da infraestrutura de transportes e logística da faixa geográfica que pretende conectar o Porto de Santos, no Oceano Atlântico aos portos marítimos de Peru e Chile, no Oceano Pacífico, designada Eixo Interoceânico Central. Para compreender tais motivações, o trabalho está dividido em quatro partes que se complementam no decurso e se interconectam na tessitura das considerações finais. Primeiramente é abordada a ascensão das questões econômicas nas prioridades de política externa dos países, ressignificando o contexto de atuação dos Estados no sistema internacional, que passam a ser movidos pela interdependência complexa, levando em consideração os interesses de grupos econômicos domésticos, para formatar suas preferências na formulação da política exterior. Estabelecida a base de sustentação dos argumentos, o estudo passa a enfocar o Brasil e a opção por instrumentalizar suas relações exteriores para concretizar o projeto de desenvolvimento econômico nacional. Nesta perspectiva, são abordadas as articulações de política externa brasileira, desde a década de 1930 - quando inicia um esforço integrado para industrialização e modernização econômica - até a proposta recente de inserção do país na economia mundial, empenhada em expandir as relações econômico-comerciais por meio de ações que contribuam para o aumento da capacidade competitiva das empresas frente à concorrência internacional. Entre tais ações são destacadas as relações de cooperação do Brasil com Bolívia, Chile, Paraguai e Peru, no sentido de promover o ordenamento de seus territórios sob a lógica da conformação da infraestrutura física, capaz de proporcionar fluidez para o escoamento da produção - momento em que se analisa em que medida as pretensões de expansão econômica brasileira estão voltadas aos parceiros comerciais da América do Sul, ou direcionadas a pontos mais distantes do horizonte, em direção à região da Ásia-Pacífico. / This dissertation seeks analyzing the motivations that lead Brazilian State to perform in the international arena, aiming at assure the Brazilian enterprises competitiveness in external market, specifically for politically take part and to invest resources in Initiative for the Integration of Regional Infrastructure in South America, choosing the prune of logistics and transportation infrastructure integration of the geographic extension that intents to connect Port of Santos, in Atlantic Ocean, to Peruvian e Chilean maritime, in Pacific Ocean, named Central Interoceanic Hub. To comprehend these motivations, this study is divided in four parts, that they complement each other along, and interconnect themselves at organization of final considerations. Firstly, it is approached the ascension of economical issues in the countries foreign politics priorities changing the States acting context in the international system, that became moved for complex interdependence, considering the domestic economical groups interests of shaping preferences on foreign politics formulation. Settled the arguments sustentation basis, the study highlights Brazil and the option for external relations way as achieve national economical development project. In this regard, the articulations to Brazilian foreign politics are approached, since 1930's - when it was began an integrated effort for economical modernization and industrialization - to recent purpose to insert nation on worldwide economy, engaged to expand the commercial-economical relations through actions in spite of contribute to increase the enterprises competitive capacity in front of international competition. As such actions, the emphasis is given to the cooperation relations of Brazil with Bolivia, Chile, Paraguay and Peru in regards to promote the ordering of their territories under the logic of physical infrastructure shaping able to allow fluidity to production flowing off - at this point, it is analyzed which extent the will of Brazilian economical expansion are toward to commercial partners of South America, or directed to farthest at the horizon, aim for Asia-Pacific region.
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