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MODELLING WIND FLOW THROUGHCANOPIES SYSTEMS USING OPENFOAM.Maldonado, Jose Miguel January 2012 (has links)
The most proper emplacements for set a wind farm are already taken or cannot be used forenvironmental causes. So in order to check the viability of the complex terrain locations whichare still available Computational Fluid Dynamics tools are used. As the commercial codes arenot flexible enough and very expensive, an open software will be used OpenFOAM.OpenFOAM needs a code for accomplish the simulation; this code is programmed in C++. Theterrain roughness, the Coriolis force and the gravity force were developed, so the next step willbe to include the effect of canopies systems in the flow simulations.Although it could be considered as roughness, it is suggested to add a forest canopy model inorder to forecast the behaviour of the wind flow over the forests.Along this document it will be shown the process followed in order to insert the canopiessystems in the CFD software. This achievement has two mains goals: Pre-processing tool which will insert the canopy parameters in the mesh of thedomain. This application will situate the forest along the studied case. The second goal is to develop a solver which take into account the effect caused by thecanopy.Once both of them are made, as there is no software which includes this kind of obstacles inthe airflow, the results just can be checked by an experimental research but that experiment issuggested as future work because it is out of this thesis. So it will be checked that the canopyparameters are uploaded to the case, and that the airflow is disturbed in a consequently wayby any forest.
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Análisis mecánico y numérico del terreno de cimentación en plataformas eólicas offshoreSoriano-Vicedo, Jorge 09 February 2024 (has links)
Durante las últimas décadas, la sociedad y la economía han mostrado un fuerte compromiso con las energías renovables en general, y con las energías marinas en particular. Este enfoque se refleja claramente en la Agenda 2030 y en los Objetivos de Desarrollo Sostenible (ODS), especialmente en el ODS 7, que se centra en asegurar el acceso a una energía moderna y sostenible. Además, los ODS 13 y 14 resaltan la importancia de combatir el cambio climático, sus efectos y utilizar de manera sostenible los recursos marinos. Dentro de las energías renovables marinas, la energía eólica marina ha sido la que ha experimentado mayores avances tecnológicos y una mayor implantación. Por este motivo, gran parte de las investigaciones científicas realizadas recientemente en el campo de las energías marinas han estado enfocadas en revisar, debatir y cuestionar los diseños de los elementos estructurales y las cimentaciones de los parques eólicos offshore. Las incertidumbres presentes en este campo de la ingeniería se deben en gran medida a la limitada experiencia del sector, el cual solo cuenta con unas pocas décadas de implementación, así como a las constantes modificaciones y discrepancias en las normativas existentes. Estas investigaciones y reflexiones se han vuelto esenciales para garantizar el desarrollo sostenible y efectivo de la energía eólica marina, impulsando su potencial como una fuente valiosa y respetuosa con el medio ambiente en el panorama energético global. Basándose en los fundamentos anteriores, esta investigación ha llevado a cabo un análisis exhaustivo del proceso de hinca de las cimentaciones de los monopilotes tanto en condiciones secas como en condiciones sumergidas. Este estudio del proceso de hinca se ha llevado a cabo mediante un ensayo a escala reducida en el laboratorio de estructuras de la Universidad de Alicante. Para ello, se han tenido en cuenta diversas variables involucradas en los parques eólicos marinos como el material empleado del monopilote, la arena del lecho marino o la velocidad y fuerza de hincado. Por último, los valores obtenidos en los ensayos que se describen en los siguientes apartados han sido comparados con modelos de elementos finitos con la finalidad de obtener una relación entre el ensayo a escala en el laboratorio y los ensayos que se podrían realizar a escala real.
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Ammonia Production from a Non-Grid Connected Floating Offshore Wind-Farm: A System-Level Techno-Economic ReviewParmar, Vismay V. 19 March 2019 (has links) (PDF)
According to U.S. Department of Energy, offshore wind energy has the potential to generate 7,200 TWh of energy annually, which is nearly twice the current annual energy consumption in the United States. With technical advances in the offshore wind industry, particularly in the floating platforms, windfarms are pushing further into the ocean. This creates new engineering challenges for transmission of energy from offshore site to onshore. One possible solution is to convert the energy produced into chemical energy of ammonia, which was investigated by Dr. Eric Morgan. In his doctoral dissertation, he assessed the technical requirements and economics of a 300 tons/day capacity ammonia plant powered by offshore wind. However, in his dissertation, one of the assumptions was connection to the grid which provided auxiliary power to keep the ammonia plant operational and produce at rated capacity. It also allowed selling of excess power to the grid in the scenario of excess power production by wind farm during high winds.
This thesis explores the technical and economical feasibility of a similar system, except that the ammonia plant will be on a plantship and there is no connection to the grid. This creates a challenge as the ammonia synthesis plant must operate between 65-100% loads. Thus, the concept of multiple mini-ammonia plants is used to address the scenario of wind energy production at less than rated power. This will allow operation of one or more mini-ammonia plant (corresponding to the available energy from offshore wind). In the event of wind speed lower than the cutoff wind speed for the turbine, the ammonia plant will use the produced ammonia as fuel, with the help of a gas turbine running on either Brayton cycle or combined cycle, to keep the plant idling. It will maintain the reaction conditions of the synthesis chamber and will not produce any ammonia. This is an important step as it takes days to reach the reaction conditions to start ammonia production again after shutting down due to unavailability of energy at low winds. Thus, at any windspeed, a mini-ammonia plant would either idle or operate between 65-100% load. This model will be used to simulate the total energy consumption, total energy captured by the wind farm, and the total ammonia produced. This will further help in assessing the final cost of producing, transporting, and consuming ammonia as fuel and thereby provide a better understanding of the feasibility of implementing this technology.
According to U.S. Department of Energy, offshore wind energy has the potential to generate 7,200 TWh of energy annually, which is nearly twice the current annual energy consumption in the United States. With technical advances in the offshore wind industry, particularly in the floating platforms, windfarms are pushing further into the ocean. This creates new engineering challenges for transmission of energy from offshore site to onshore. One possible solution is to convert the energy produced into chemical energy of ammonia, which was investigated by Dr. Eric Morgan. In his doctoral dissertation, he assessed the technical requirements and economics of a 300 tons/day capacity ammonia plant powered by offshore wind. However, in his dissertation, one of the assumptions was connection to the grid which provided auxiliary power to keep the ammonia plant operational and produce at rated capacity. It also allowed selling of excess power to the grid in the scenario of excess power production by wind farm during high winds.\\ \par This thesis explores the technical and economical feasibility of a similar system, except that the ammonia plant will be on a plantship and there is no connection to the grid. This creates a challenge as the ammonia synthesis plant must operate between 65-100\% loads. Thus, the concept of multiple mini-ammonia plants is used to address the scenario of wind energy production at less than rated power. This will allow operation of one or more mini-ammonia plant (corresponding to the available energy from offshore wind). In the event of wind speed lower than the cutoff wind speed for the turbine, the ammonia plant will use the produced ammonia as fuel, with the help of a gas turbine running on either Brayton cycle or combined cycle, to keep the plant idling. It will maintain the reaction conditions of the synthesis chamber and will not produce any ammonia. This is an important step as it takes days to reach the reaction conditions to start ammonia production again after shutting down due to unavailability of energy at low winds. Thus, at any windspeed, a mini-ammonia plant would either idle or operate between 65-100\% load. This model will be used to simulate the total energy consumption, total energy captured by the wind farm, and the total ammonia produced. This will further help in assessing the final cost of producing, transporting, and consuming ammonia as fuel and thereby provide a better understanding of the feasibility of implementing this technology.
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Perception of scale and scale effects in the landscape, with specific reference to wind turbines in ScotlandStanton, Caroline Mary January 2016 (has links)
Perception of scale is important to our activity within a space and to our experience of a landscape. This presents a problem if people cannot predict or convey the scale effects of large structures proposed in a landscape, as has been the case for recent wind turbine proposals in Scotland. To address this problem, this research explored how people perceive scale and scale effects in a landscape. It took wind turbines as an example structure and analysed how different scales of windfarm create different scale effects in different landscapes, as well as how to best assess and communicate these effects. The research applied three methods to address the research questions: Landscape and Visual Impact Assessment (LVIA), which is a standard, structured process applied by professional landscape architects; experiential landscape assessment, which included semi-structured interviews with local people in addition to site assessment; and public attitude and preference study, which included Adaptive Choice-Based Conjoint analysis (ACBC). These different methods allowed the research questions to be explored in different ways, while overlapping in some aspects and providing triangulation. The research findings revealed that our perception of scale and scale effects in a landscape is influenced by numerous attributes and depends on how these are experienced together. Building upon the theoretical background, an important difference between visual scale and spatial scale was highlighted, as well as alternative ways in which scale references are made. Throughout the research, the need for clear communication was emphasised and the findings included identifying the specific words that people use to describe scale effects in the most discriminating way. This research supported other studies in finding that consultation with local people (professionals and the public) was vital to understand in sufficient depth how a landscape was perceived, experienced and valued. In addition, the innovative development of Conjoint Analysis demonstrated how this method can reveal how people judge the relative importance of different attributes that influence landscape and visual effects and, by doing so, offer new possibilities as a tool in landscape research. Building upon the general findings concerning scale, specific findings regarding the scale effects of windfarms included: greater influence of the proximity of a windfarm than size or numbers of wind turbines; greater importance for being in private and/or fixed locations that offer a sense of refuge compared to public locations and/or when moving; the importance of collective effects perceived and experienced by a community; the importance of perceived spatial separation between a viewer and a windfarm (affecting sensitivity to scale effects within open settings); and differences in how people judge the importance of horizontal scale effects compared to vertical scale effects. The research findings contribute to the knowledge and understanding of people’s perception of scale and scale effects in a landscape and they counter some common assumptions and current practice in landscape architecture. They can be applied in practice and policy to help assess scale effects, convey more clearly to people the type of scale effects and how these will affect them, and minimise the adverse scale effects of windfarms through siting and design. The thesis also identifies how to build upon these findings in the future, including recommendations for additional research, new approaches to assessment (including the use of prompt lists) and thresholds for acceptability of scale effects.
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Power Loss Evaluation of Submarine Cables in 500 MW Offshore Wind FarmJayasinghe, Lahiru Kushan January 2017 (has links)
The main objective of this thesis is to develop a new methodology to evaluate the transmission cable losses of wind-generated electricity. The research included the power loss variations of submarine cables in relation to the line length, cable capacity and the transmission technology in an offshore wind farm having a capacity of 500 MW. The literature of similar studies helped to generate a solid background for the research. The comprehensive analysis carried out is based on a hypothetical wind farm and using three different power transmission wind farm models to investigate the technical reliability of transmission technology, namely, High Voltage Alternative Current (HVAC), High Voltage Direct Current Voltage Source Converter (HVDC VSC) and High Voltage Direct Current Line Commutated Converter (HVDC LCC). The analyses carried out are performed under assumptions and simplifications of power system models to evaluate the submarine cable transmission losses of 3 different transmission systems by using the MATLAB/ Simulink software. With relevance to the simulation results, the HVAC submarine cable has more losses than any other transmission technology cables and it is suitable for short distance power transmission. The VSC technology has less losses than HVAC. Comparing with afore-mention technologies the HVDC LCC technology transmission links have the lowest line losses. Moreover, the transformer losses and the converter losses were calculated. The simulation results also included the overall power system losses by each of the transmission models.
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