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Xia, Jiyang. "Numerical study on wind field and air pollutant dispersion in urban street canopies." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22752857.
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Zarovy, Samuel R. "Improved gust rejection for a micro coaxial helicopter in urban environments." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52992.
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Due to their small size, relative covertness, and high maneuverability, micro rotorcraft are ideal for a plethora of civilian and military applications in an urban environment such as, surveillance, monitoring, mapping, and search and rescue. It is envisioned that these vehicles will operate indoors confined complex spaces, and outside near the ground—among buildings and other obstacles. The aerodynamic velocity fields in these areas are notoriously complex with the mean winds varying spatially and temporally with sharp changes in wind magnitude and direction over small distances. This results in velocity perturbations which are on the same order of magnitude as the maximum flight speeds of micro rotorcraft leading to stall, large attitude perturbations, and loss of control; thus preventing micro rotorcraft from carrying out even the most basic missions.
This dissertation starts to fill the void in the literature on this topic by assessing how to design a micro coaxial helicopter with improved gust response in complex urban environments. Both experimental flight tests and modeling and simulation tools are developed and executed to analytically understand the challenges and potential solutions to enable rotorcraft to operate efficiently and robustly in urban environments. A set of performance metrics were developed to provide a framework to assess mission-level performance of micro rotorcraft in both flight experiments and simulation trade studies. A high fidelity dynamic model of a coaxial helicopter was developed to accurately simulate vehicle response to urban wind disturbances. The model was validated using flight experiments in a motion capture facility. Additionally, a dynamic inversion based Gust Rejection Control architecture was developed for the dynamic simulation which included a novel wind estimation algorithm that was utilized to improve controller performance and create a flight envelope protection scheme. The high fidelity dynamic model was employed to perform a variety of trade studies to: analyze vehicle response to prototypical urban wind kernels, understand the affect of wind estimation on the control architecture, assess the level of model fidelity required to adequately simulate vehicle response to urban winds, and identify key platform design parameter trends to improve wind disturbance capabilities. Overall the results show the challenges micro rotorcraft face in urban environments while highlighting some trends that can be helpful for future design and analysis efforts.
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Mendes, Flávio Henrique. "Vulnerabilidade à queda de árvores por meio de simulações microclimáticas." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-22062016-165232/.
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Muitos são os benefícios provenientes da arborização de vias públicas, como aumento da vida útil do asfalto por meio do sombreamento, filtragem de poluentes, absorção de CO2, interceptação da água da chuva e da radiação solar e mitigação de ilhas de calor; porém, por questões culturais, é considerada muitas vezes pela população como algo negativo, cujas folhas entopem calhas, raízes destroem calçadas, troncos e folhas atrapalham fiação elétrica e, principalmente, elas estão susceptíveis às quedas. A pesquisa teve como objetivo estudar o comportamento das quedas de árvores no município de Piracicaba/SP, Brasil, com atenção especial ao regime de ventos na cidade, baseado em dados fornecidos pelo Corpo de Bombeiros de Piracicaba, Secretaria de Defesa do Meio Ambiente de Piracicaba (SEDEMA) e Estação Meteorológica da Escola Superior de Agricultura \"Luiz de Queiroz\" (ESALQ). De caráter inédito, o principal resultado foi a relação direta entre quedas e zonas urbanizadas, que, em constantes alterações no uso do solo, acabam por danificar a sustentação das árvores (raízes), fato justificado pela alta concentração de quedas na parte central (36,7%), com destaque para as estações da primavera e do verão, ou seja, ventos e chuvas, na qual, juntas, somaram 78,0% do total. O período de retorno esperado para ventos superiores a 75 km h-1, classificados como temporais na Escala de Vento de Beaufort, foi de 2,8 eventos por ano. Enquanto verificou-se o predomínio de ventos alísios de sudeste, pertencentes ao quarto quadrante, a direção das rajadas de vento teve maior variação e, assim, com predomínio daqueles ventos, é recomendável instalações de parques industriais nas zonas norte, noroeste e oeste, haja vista a importância de evitar que os poluentes adentrem a cidade. As espécies de maior vulnerabilidade foram: Pachira aquatica Aubl. (monguba), Handroanthus sp. (ipê roxo) e Tipuana tipu (Benth.) Kuntze (tipuana). Por meio de simulação microclimática computacional, utilizando o programa ENVI-met versão 3.1, em dois estudos de caso, sendo um em bairro residencial e outro na Praça José Bonifácio, foi possível identificar locais de maior atenção quanto às quedas de árvores, em função da rugosidade do local, capaz de alterar a velocidade e a direção do vento.There are many benefits from public roads afforestation, such as longer pavement life through shading, filtering pollutants, CO2 absorption, intercepting rainfall and solar radiation and mitigating heat islands; however, due cultural issues, is often regarded by the population as something negative, whose leaves clog gutters, roots destroy sidewalks, stems and leaves disrupt electrical wiring and, mainly, they are susceptible to falls. The research aimed to study the behavior of falling trees in Piracicaba/SP, Brazil, with special attention to the wind regime in the city, based on data provided by the Piracicaba Fire Department, Secretariat of Defense of the Environment of Piracicaba (SEDEMA) and Meteorological Station Luiz de Queiroz College of Agriculture (ESALQ). From unedited character, the main result was the direct relationship between falls and urbanized areas, which, in constant changes in land use, end up damaging the support of trees (roots), a fact explained by the high concentration of falls in the central part (36.7%), highlighted to the spring and summer seasons, i.e., winds and rains, which, together, totaling 78.0% of the total cases. The payback period expected to winds who exceeding 75 km h-1, classified as storms in the Beaufort Wind Scale, was 2.8 events per year. While there was a predominance of trade winds from the Southeast, belonging to the fourth quadrant, the direction of the gusts of wind had greater variation and, thus, with those predominant winds, it recommend installation of industrial parks in North, Northwest and West areas, since the importance of avoiding that pollutants enter into the city. The most vulnerable species were: Pachira aquatica Aubl. (Guiana Chestnut), Handroanthus sp. (Purple Ipe) and Tipuana tipu (Benth.) Kuntze (Tipuana). Through computational microclimate simulation, using the software ENVI-met version 3.1, in two case studies, being one in a residential area and another in the José Bonifácio Square, it was possible to identify locals of more attention as the falling trees, based on the local roughness, able to change the speed and direction of the wind.
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Melo, Beatriz Cristina Barbalho de. "Estudo do campo térmico: o caso do Campus IV - UFPB." Universidade Federal da Paraíba, 2015. http://tede.biblioteca.ufpb.br:8080/handle/tede/8993.
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The microclimate consequences of a particular place to demonstrate that he as urban growth and exploitation of natural resources are increasing unfortunately. The weather is the most important component in maintaining the ecological balance. And his study becomes complex due to the various facets that involve him, turning indispensable interdisciplinary study, it could help in the reduction and / or more efficient solution of the urban problems. Studies of this order become relevant to planning and environmental management, which arouses interest for research on the thermal field of urban areas. The problem of this research is related to concern about anthropogenic implications on the local microclimate. It is known that human actions on the microclimate and the lack of proper planning of a particular place, can contribute to the thermal discomfort of users and demand higher energy costs. The present search, has as main objective to analyze the field thermal the Campus IVUFPB, located in the city of Rio Tinto-PB. In this case, seeks if relate the anthropogenic actions with the main thermal problems, detected on site. To obtain microclimate data, were installed in similar (which takes into account the type of soil cover, in this case, coating in cementitious composition) points, measuring equipment, in six points within the campus IV- UFPB, in dry season (from March 04 to April 7, 2015) and during the rainy season (from 09 June to 13 July 2015), totalizing 35 days in each measurement period. From the analysis and management of the data obtained, the presence of heat islands was detected within the study area as well as the rise in temperature in places with low circulation of winds and decreased moisture and the low individuals presence of arboreal. The results allowed the elaboration of suggestions with proposed thermal environmental, as; the ceramic roof replacement, in the hottest areas for green cover; replacing paving stones and interlocked block, per tread grass, that provide the minimization of thermal effects identified in the Campus IV-UFPB. With this, this research, can to corroborate to reveal the adverse effects of the anthropogenic actions that provoke microclimatic modifications in the thermal field of Campus IV-UFPB, making a relation with its urban components.
As consequências microclimáticas de um determinado local demonstram o quão desastrosamente o crescimento urbano e a exploração dos recursos naturais vêm aumentando. O clima é o componente mais importante na manutenção do equilíbrio ecológico. E seu estudo se torna complexo devido às diversas facetas que o envolvem, tornando imprescindível o estudo interdisciplinar que pode auxiliar, na diminuição e/ou solução mais eficiente das problemáticas do meio urbano. Estudos dessa ordem se tornam relevantes para o ordenamento e a gestão ambiental, o que desperta interesse para pesquisas sobre o campo térmico de áreas urbanas. A problemática desta pesquisa está relacionada com a preocupação sobre as implicações antrópicas sobre o microclima local. Sabe-se que as ações antrópicas sobre o microclima e a falta de planejamento adequado de um determinado local, podem contribuir para o desconforto térmico dos usuários e demandar maiores custos energéticos. A presente pesquisa tem como objetivo geral analisar o campo térmico do Campus IV-UFPB, localizado na cidade de Rio Tinto-PB. Nesse caso procura-se relacionar as ações antropogênicas com as principais problemáticas térmicas, detectadas no local. Para a obtenção de dados microclimáticos, foram instalados, em pontos semelhantes (que levam em consideração o tipo de recobrimento do solo, neste caso, revestimento de composição cimentícia), equipamentos de medição, em seis pontos dentro do campus IV-UFPB, no período seco (de 04 de Março a 07 de Abril de 2015) e no período chuvoso (de 09 de Junho a 13 de Julho de 2015), somando-se 35 dias em cada período de medição. A partir da análise e ordenamento dos dados coletados, ficou constatada a presença de ilhas de calor dentro da área de estudo, bem como o aumento de temperatura em locais com pouca circulação dos ventos e a diminuição da umidade em locais com pouca presença de indivíduos arbóreos. A análise dos resultados permitiu elaborar sugestões com propostas termo ambientais do tipo, substituição de telhado cerâmico, nas áreas mais quentes, por telhado verde extensivo; a substituição de paralelepípedos e blocos intertravados, por piso grama que proporcionem a minimização dos efeitos térmicos identificados, no Campus IV-UFPB. Com isso, esta pesquisa, pode vir a corroborar no desvendar dos efeitos adversos das ações antropogênicas, que provocam alterações microclimáticas no campo térmico do Campus IV-UFPB, fazendo uma relação com seus componentes urbanos.
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Dosset, Pablo. "Urban Wind Power : Installation of an Urban Wind Power turbine in Polhemsskolan in Gävle." Thesis, University of Gävle, Department of Technology and Built Environment, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-760.
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Urban wind power is not too developed yet. Only some years ago some countries started to be aware of the important source of energy that can be used within built-up areas. The U.K., the Netherland, France and Italy are already working on it, but they are still far away to reach models and equations that can be useful for any situation.
An urban turbine is going to be installed in Gävle, Sweden, in the roof of Polhemsskolan. Therefore, the wind velocity should be found out to come up with some results about the energy yield. But some problems appear when try to estimate that velocity.
To calculate this velocity three different ways can be used. They are Mathematical models, Measurements and Simulations or Computational Fluid Dynamic (CFD) calculations. All of them are quite difficult to use. Both mathematical models and CFD are very expensive as well as they need too much time to give a result. In addition, the area where the rotor is going to be installed is quite strange and therefore, it is even more difficult to put all the data in the mathematical model or CFD. On the other hand, measurements were almost impossible to carry on. The measurement of the wind velocity should be done during one year due to the big differences in that value depending on the season; winter, summer... depending on the weather; cloudy, sunny and so on. This thesis was only four months long and that was not enough to do it. It has been tried too to use any measurements that could be in any weather stations in the surrounding of Gävle. Nothing was found. No wind velocity measurements have been made in this area.
Hence, different books and reports about this topic have been study quite depth. Most of them from the U.K. Estimations and assumptions were taking into account to come up with different solutions to make easier in the future to calculate an energy yield when measurements will be done.
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Bottema, Marcel. "Wind climate and urban geometry /." Online version, 1993. http://bibpurl.oclc.org/web/24411.
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Drew, Daniel. "Analysis tools for urban wind turbines." Thesis, University of Reading, 2011. http://centaur.reading.ac.uk/35837/.
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With the UK seeking to increase the contribution of microgeneration, the number of small wind turbines installed in urban areas has increased. However, a wide-spread experience is that urban located turbines have generated considerably less energy than anticipated. This thesis demonstrates that poor turbine placement, due to inadequacies in commonly used wind resource modelling and assessment techniques, has played a large part in this disappointing outcome. The current site assessment tools estimate a turbine's performance at a potential site using a method developed for large scale wind energy projects in rural areas. Using data measured at 91 Met Office weather stations across the UK and a rooftop site in London, this thesis shows that when applied in urban areas, this method can lead to large errors in the predicted energy production of a small wind turbine. The magnitude of these errors is such that the tools cannot consistently identify the economic viability of a turbine/site combination. This is largely due to a simplified representation of the site's wind resource. By not considering the decelaration of the wind by friction, there are large errors in the predictions of a site's annual mean wind speed. Across the sites there is a mean error of over 40% and 18% for the DECC wind speed database and the Carbon Trust tool respectively. Furthermore, analysis of data collected at the roof top site shows that due to high levels of turbulence in urban areas, a Weibull distribution does not provide a sufficient representation of the temporal variability of a site's wind resource. 1 Subsequently the thesis develops an improved, more reliable means of predicting mean wind speed at urban sites by considering interactions between the flow and the morphology of built-up areas in more detail than has been possible previously. When applied to the Greater London area the model shows that turbines generally perform better towards the outskirts of the city, however there are some sites with good wind resource close to the city centre with low aerodynamic roughness.
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Claus, Jean M. "Wind direction effects on urban flows." Thesis, University of Southampton, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.560582.
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In the research on urban flows, two trends can be distinguished: some studies based on real urban environments, either in the field or on reproductions; and some on simplified models. One such model, a staggered cube array, has been investigated extensively, both experimentally in wind tunnels and numerically using LES and DNS, but always with a flow direction normal to the faces of the cubes. We are here investigating the effects of different wind directions on the flow within and above the cube array. As no other study has been published on the subject, both numerical and experimental investigation methods have been used. For the numerical side, large-eddy simulations were conducted using the finite volume method implemented in commercial software (StarCD, CD-adapco). The half-channel flow simulated was driven by a momentum source equiva- lent to a pressure gradient. The results are shown to agree well with those of wind-tunnel experiments conducted in parallel. For the experimental side, the boundary layer flow is measured in two dimensions using particle-image velocimetry and the drag using pressure tapped cubes and a drag balance. The results show that the mean flow field within the canopy is only weakly dependent on the direction of the flow above. Above the canopy, the mean velocity profile, time av- eraged and spatially averaged in horizontal layers, is shown to include an inertial sublayer where a logarithmic profile can be fitted. The fit proves to be best by considering for zero-plane displacement the height at which the mean drag acts and points arguably in the direction of a flow dependent value of the Von Karman constant. At the top of the numerical domain, the mean flow is also deviated from the direction of the forcing. We show that this deviation is directly related to previously unseen lift forces applied on the cubes. On balancing the different forces in the numerical domain, the viscous contribu- tions to both the lift and the drag forces are shown to be larger than anticipated from previous studies. Although these results could not be validated by the experiments as the viscous forces remain small compared to the experimental errors, such contributions raise concerns with regards to the Reynolds number independence of the flow and to the need for more complex wall conditions for LES. Overall, the variations of the flow pa- rameters are not negligible and prove to be non-linear and non-monotonic with the flow angle which highlights the importance of considering the flow direction when studying or parameterising urban landscapes. 1.
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Dymock, Ben R. "Urban wind turbines : a feasibility study." Thesis, London South Bank University, 2017. http://researchopen.lsbu.ac.uk/1864/.
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There is an existing body of research into noise, vibration and wind regime concerns associated with urban wind turbines demonstrating the detrimental effects of these topics on the energy yield potential and therefore financial worth of an installation. Much of the research has focused on wind regime assessment and optimum roof top placement via CFD modeling offering generalised guidelines showing a potential for wind power to contribute towards lowering London's CO2 emissions. Unfortunately, without benefiting from appropriate planning assessment, a number of early urban turbines failed and have risked irreversibly tarnishing the concept. Hitherto no studies have been specifically conducted on the urban potential of building integrated wind turbines. As integration is bespoke, typically determined by the architecture, it is unknown whether existing guidelines for roof mounted wind turbines could be directly applied. It is probable that each installation would merit its own assessment and analysis procedure. This study aims to investigate the differences between roof mounted and building integrated turbines in terms of assessment, operation and urban potential. In response to these differences it is intended to demonstrate how a successful installation can be achieved. Comparisons between two urban sites, one smaller, roof mounted HAWT and one larger, building integrated HAWT have been made via noise, vibration, CFD and atmospheric data recorded and analysed over two years to build a comprehensive understanding of the inherent urban issues. The prospect of successfully situating an urban turbine is complex in nature and considering the high installation costs and high level of design and engineering required to do so it is imperative that their energy yield provide a satisfactory return on investment and efficient supply of power without adversely impacting upon the surrounding environment or themselves. This study concludes that a multifaceted approach is necessary to achieve an efficient building integrated turbine, comprised of: (i) accurate local noise surveys to establish the local acoustic environment to inform acceptable turbine operating ranges, (ii) specific noise modeling of manufacturer provided data or, where none is available, acoustic testing of the proposed turbine across all applicable wind speed ranges, (iii) comprehensive vibration assessment, not only of the turbine tower/system but also of the turbine housing and any lower residential floors to ensure no natural frequencies will be excited and to prevent any vibration transmission via appropriate mounting, isolation or damping where necessary, (iv) the acquirement of site specific wind data to inform architectural design, turbine selection and placement. If monitoring at hub height is not possible it has been found that it may be acceptable to monitor in close proximity and then extrapolate the results using CFD analysis and wind profile methods, (v) CFD modeling of the surrounding topography, the turbine mount and/or enclosure. These areas are discussed with potential areas of noise and vibration control and turbine optimisation, specific to the case studies, investigated. Further to the aforementioned study an investigation into a new method of assessing noise and vibration levels associated with average anemometry recorded wind speeds has been presented so as to attain average levels per wind speed bin without being skewed by impulsive gusts.
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Peregrino, Paulo Sérgio Araújo. "A influência do padrão de adensamento nas características de um escoamento urbano : uma aplicação à região do Altiplano Cabo Branco em João Pessoa-PB." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/180629.
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Faz-se notória a ideia de que o crescimento das cidades e o consequente aumento no adensamento das mesmas é, nos dias atuais, um fato inevitável; e que o homem, ao modificar o meio natural, o faz quase sempre de forma danosa. Formação de ilhas de calor, aumento do consumo de energia, dificuldade na dispersão de poluentes, diminuição do ângulo de visão do céu, diminuição da taxa de permeabilidade do solo entre outros, são problemas frequentemente relacionados com a densificação e verticalização das cidades. A utilização de modelos reduzidos para simulações experimentais em túneis de vento das condições naturais de ventilação se mostram eficazes, além de reduzir custos em pesquisas nesta área. Embasando-se em tais pressupostos, o presente trabalho pretende verificar as alterações das características dos escoamentos de vento provocadas por distintos padrões de ocupação do solo urbano no bairro do Altiplano Cabo Branco, na cidade de João Pessoa-PB. A área em estudo atravessa um processo acelerado de modificação nas suas características de ocupação urbana, conduzido pelas alterações dos indicadores urbanísticos locais, antes mais restritivos, possibilitando agora edificações com gabaritos em altura significativamente maiores do que os anteriormente observados no local. Parte-se então da hipótese de que o processo de verticalização resultante deste crescimento é capaz de alterar os escoamentos de ventos não apenas nas áreas onde este ocorre, mas também em áreas contíguas. No desenvolvimento deste trabalho, de caráter experimental, foram avaliados dois modelos de adensamentos urbanos para a área de estudo O primeiro deles reproduz a ocupação da área conforme se encontrava antes de mudanças ocorridas nos indicadores urbanísticos para o local. O segundo apresenta a configuração atual de ocupação da área, delineada pela legislação em vigor. Para viabilizar esta avaliação serão realizados ensaios no Túnel de Vento de retorno fechado, Professor Joaquim Blessmann, do Laboratório de Aerodinâmica das Construções da Universidade Federal do Rio Grande do Sul, utilizando maquetes (modelos) em escala reduzida e observando os requerimentos necessários estabelecidos para este padrão de estudo experimental. Foram utilizados nos ensaios para cada uma das duas configurações de vizinhança dois ângulos de ataque de vento, 150 e 90 graus, tomando como referência o atlas de vento do local de estudo. A partir da análise dos resultados obtidos é possível concluir que a verticalização, da maneira como propõe legislação atual para a área, não apresenta perdas significativas no que se refere aos escoamentos (ventos) quando comparada com o padrão de ocupação anterior sem os edifícios altos. As áreas adjacentes também não sofrem maiores prejuízos no que se refere aos escoamentos quando comparados os dois modelos.What is worth elucidating is the idea about city expansion and consequent increasing effects of the densification is, now are days, an unavoidable fact; and that human, by modifying the natural environment, does so always in a destructive way. Formation of heat island, increase of the energy consumption, difficulty in the dispersion of pollutants, reduction in the sky view angle, diminution of the level of soil permeability among others, are problem frequently related to densification and verticalization of cities. The use of reduced models for experimental simulation in wind tunnel considering natural conditions of ventilation prove to be effective, apart from low down cost of experiments in this area of research. Based on such assumption, the aim of this research was to verify the alterations of wind flow characteristics provoked on distinct occupation pattern of urban soil in the district of Altiplano Cabo Branco, in the city of João Pesssoa-PB. The studied site passed through a fast process of physical modification in its urban occupation characteristics, conducted by local urban indicators, which was earlier more restrictive, presently permitting building with considerable standard that are higher than those, which were formerly observed on site. Based on the assumption that the process of verticalization as a product of growth may alter the wind flow not only in the areas where it occurs but also in adjacent areas In developing this work, experimentally, two models of urban concentrations were examined on the study area. The first was reproduced on the occupation of the area as it was founded before the changes in the local urban indicators. The second shows the current configuration of occupation of the area outlined by the current legislation. To make this assessment tests were carried out in the Boundary layer wind tunnel, Professor Joaquim Blessmann, of Federal University of Rio Grande do Sul, by use of model building of reduced scale and observing the necessary requirements established for this standard experimental study. Two angles of attack of wind were utilized in the two experiments, 150 and 90 degrees, with reference to the wind atlas of site of study. From the result of this analysis we conclude that virtualization of the occupation proposed by the current proposed legislation for the site does not present significant losses when compared with the previous standard of occupation lacking the tall buildings. Adjacent areas do not affected by losses in relation to the wind flow of the two models that was compared.
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Shi, Yu. "Colonizing the urban wilds: invader or pioneer?" The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366333944.
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Dadioti, Rallou. "Numerical wind resource assessment in urban environments." Thesis, De Montfort University, 2017. http://hdl.handle.net/2086/14219.
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This thesis leads to a framework for micrositing, the process through which the specific location for mounting micro wind turbines in urban environments is determined. It can be used as a guidance on how to model an area of interest, find the optimum location for micro wind turbines installation and calculate the annual energy production, commenting on the accuracy that can be expected from the results. Essentially, it is composed of three parts, each one deals with different set of tasks associated with model development and simulation. The first part investigates the computational practices to the fields of turbulence in urban environments implemented in the open-source CFD library OpenFOAM. It examines the performance of a turbulence model, known as DES, which has not been previously used for external flows in complex urban environments and concludes that this approach offers improved robustness and accuracy over a range of wind conditions. It offers improved prediction of flows in wake regions compared to RANS methods and is less computationally demanding than full LES approaches. The validity of DES implementation is tested using data sets derived from both wind tunnel experiments and field measurements. In the second part, a procedure is developed to identify the optimum location for mounting wind turbines, based on the spatial variations in mean annual wind speed and the corresponding annual energy production (AEP). The procedure utilizes one year of measured wind data for one site to extrapolate (using the `Wind Atlas Methodology') the annual wind speed at the site of interest. Then combining the climate data with the CFD results and the power characteristics of the micro wind turbines, it estimates the mean wind speed and the annual energy yield. Essentially, this methodology leads to the formation of three dimensional fields of the average annual wind speed and the AEP (3d wind maps), which will enable identification of the effects of the complex urban topography on the wind flow, and the potential locations for micro wind turbines installation. The third part examines the accuracy that can be expected from the annual energy production estimation techniques and provides guidelines on the calculations. In particular, it investigates the validity of the standard power curves for the site-specific air density and evaluates their effect on the annual energy production estimations. Differences of the order of 10-3 between the default and the site specific mean air density (ρ), do not change substantially the energy production. However, for higher discrepancies of the order of 10-2 the power output can differ more than 10%. Turbulence affects the wind energy in two ways: through power performance impacts and through effects on turbine loads and fatigue. In the operational range of each turbine, TI increases the output at low wind speeds, while in the transition region to rated power it decreases the power output. In the context of this study, the DES approach was implemented to examine the flow at the De Montfort university campus in Leicester. The 3d wind maps for the mean wind speed and the annual energy production were developed and the optimum locations for micro wind turbines installation were identified. Although the rooftops of the higher buildings have mostly the potential for wind energy applications, the effect of the urban topography on the wind potential is not always apparent. Lower building can occasionally have higher potential for micro wind turbines installation than taller and roofs of the same height and close each other may differ substantially in their predicted energy output. Using the field measurements by two 3d ultrasonic anemometers placed in the campus, the site specific air density and turbulence intensity were considered to correct the energy yield estimations and evaluate their effect on the results.
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Millward-Hopkins, Joel Thomas. "Predicting the wind resource available to roof-mounted wind turbines in urban areas." Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/5267/.
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Anthropogenic climate change is one of the most difficult challenges currently faced by society, and in order to prevent the most dangerous scenarios from occurring it is essential that human activities and behaviour in the industrialised world are made environmentally sustainable. A large part of these changes must involve reducing the amount of energy that we use, and changing the way in which it is produced, and here renewable energy technologies will play a vital role. The research reported in this Thesis focuses upon one such technology, namely that of wind energy in the urban environment. A major barrier to the deployment of this technology reaching its full potential is the lack of accurate and affordable methods of estimating wind speeds in urban areas. Thus, improving these methods is what this research aims to address. Firstly, by analysing a number of experimental datasets, an evaluation of currently available methods of predicting urban wind resource is undertaken in order to establish the feasibility of developing more accurate methods. Subsequently, new models are developed that allow the mapping of predicted mean wind speeds over urban areas. The accuracy of the predictions is then evaluated using measured meteorological data from various locations. An evaluation of the cumulative potential for generating wind energy in the major UK city of Leeds is then made. The models that are developed are found to improve the accuracy of estimations of surface aerodynamic parameters and mean wind speeds in urban areas, with respect to currently available models. The results highlight the importance of including the influence of building height variation and changes in wind direction in such models, and also the value of utilising detailed building geometric data as model input. Finally, the investigation of the cumulative potential for generating wind energy in Leeds indicates a largely untapped wind resource available that could allow for a significant expansion of urban wind energy. The estimates of the deployment potential of urban wind energy have practical value for turbine manufactures and urban planners alike. In addition, the wind maps presented offer a valuable means for pinpointing locations where a significant wind resource may be available, and hence where useful carbon savings can be made. Therefore, in order to maximise the impact of this research, it would be valuable for these maps to be made available and easily accessible to interested parties and individuals, and hence this is a major objective of future work.
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George, Bica. "Urban vindkraft i Malmö." Thesis, Malmö högskola, Teknik och samhälle, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-22913.
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Sverige är ett föregångsland när det gäller miljöarbetet men har inte tillhört de ledande länderna på vindkraftsområdet. Vindkraftsproduktionen i den urbana miljön är sällsynt på den svenska marknaden. Uppsatsens syfte är att undersöka vad som menas med urban vindkraft, belysa vilka problem och hinder finns för vidare utveckling och berätta om framtidsplanerna för urban vindkraft i Malmö. Vidare försöker jag även redogöra för vilken påverkan urban vindkraft har på vårt samhälle. Uppsatsen grundar sig på analys av artiklar som behandlar urban vindkraft, studier av rapporter samt intervjuer med ansvariga för dem olika projektet som pågår i Malmö idag. Studien visar att urban vindkraft är en bra och miljövänligt förnyelsebar energikälla. Det finns problem och samhälleliga konflikter som måste lösas för att urban vindkraft skall utvecklas vidare. Med hjälp av forskning, riktade satsningar och noggrann uttänkt planering kan den få plats i stadsmiljön. Utifrån studiens design, får jag uppfattningen att en utvärdering av situationen för urban vindkraft, är först möjligt om ett antal år, då alla pilotprojekt har varit igång och kan förse oss med värdefull information. Urban vindkraft skulle kunna bidra med ekonomisk och miljömässig nytta till samhällsutvecklingen i framtiden.Sweden is a leading country in environmental work but has not been among the leading countries in wind power. Wind power generation in the urban environment is rare in the Swedish market. The purpose of this thesis is to examine what is mean by urban wind power, highlighting the problems and obstacles for further development and present plans for urban wind power in Malmö. Furthermore, I try to also to explain the impact of urban wind power has on our society. The essay is based on an analysis of articles dealing with urban wind power, studies of reports and interviews with those responsible for various projects going on in Malmö today. The study shows that urban wind power is a good, environmentally friendly renewable energy source. There are problems and social conflicts to be resolved for urban wind power to be developed further. Through research, targeted investments and careful planning, wind power can devised to fit in the urban environment. Based on the study design, I believe that an assessment of the situation of urban wind power is only possible in a couple of years, when all the pilot projects have been running for a while and can provide us with valuable information. Urban wind power could contribute to economic and environmental benefits to society in the future.
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Jacobs, Stephan. "The Strategic implementation of Urban Wind Turbines within the consumer market : Visualizing the possibilities for Urban Wind Turbines in the Netherlands." Thesis, KTH, Industriell Marknadsföring och Entreprenörskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-209828.
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The last couple of years the interest of consumers for environmental products has grown. This development has resulted in new and innovative product and markets. One of these markets is the Renewable energy system (RES) market for the home consumers. The RES can be divided into Solar panels and Urban Wind Turbines (UWT), in which Solar panels are the most adopted by the consumers, but why? The most applicable system is depending on the location and environment for which UWT might be more interesting in some situations. This resulted in the research question of; ‘Why are the Urban windmills not yet adopted within the private consumer market with respect to the financial issues and the Green social status?’. The research is done for the company, Kaffee Engineering, a young innovative company in the Netherlands. Kaffee Engineering is in possession of a design of a UWT but doesn’t know how to put it into the market. The research is there to use for Kaffee Engineering to develop a strategy to innovate its product. The research is an exploratory, quantitative, applied and deductive research. In this the literature is used to create and examine a survey which is hold under the possible market group. Theories such as the Blue Ocean Stategy, Green Consumerism, and Value proposition are used to create the survey and to analyse the data. The sample group is living in North and South-Holland since this is an area where the product could be well implemented and has to be a house owner or an almost house owner. This since the average wind in this area is high and the product can be seen as an investment for the house. The total sample size of the survey is set to 68 participants to get sufficient data. The Survey shows that a market opening for the UWT is to develop a low costs and easy maintained product in which the looks are not very important. As a recommendation more research can be done in the investment options and new revenue models to create an even better Blue Ocean.
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Wang, Xiaoxue, and 王霄雪. "Exploring city-scale thermal and wind environments." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2015. http://hdl.handle.net/10722/211112.
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Hang, Jian, and 杭建. "Wind conditions and urban ventilation in idealized city models." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B42841471.
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Hang, Jian. "Wind conditions and urban ventilation in idealized city models." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B42841471.
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Bird, Caroline J. (Caroline Jennifer). "Boston's urban wilds : the persistence of an idea over time." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87524.
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Thesis: M.C.P., Massachusetts Institute of Technology, Department of Urban Studies and Planning, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 51-53).
Many city natural areas programs are constricted due to limited resources for the acquisition and management of land. Boston's urban wilds offer an alternative model for the protection of urban open space that focuses on decentralized advocacy and activism rather than on a centralized city program. This thesis analyzes the forty-year history of the urban wilds, investigating how the idea first captured people's attention and how advocates have kept it relevant over time in the face of political, economic, and social changes. The investigation shows that the urban wilds idea was successful due to the extensive support that early visionaries received to develop and implement it, and that the idea persisted beyond this early period of support because advocates were able to maintain the core vision for urban wilds while exercising flexibility and creativity in realizing it. The thesis concludes with recommendations for other cities wishing to create decentralized networks of special places and for Boston's urban wilds advocates as they move into the next period of urban wilds advocacy.
by Caroline J. Bird.
M.C.P.
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Cherry, Jonathan S. (Jonathan Sher). "The windy city : harnessing power in the neighborhood landscape." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/44363.
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Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references.
As wind power has spread in North America, so has an awareness that community acceptance will largely determine whether this renewable energy source continues to grow. Despite apparently widespread popular support for wind energy, a number of proposals for wind farms in rural and offshore locations have been derailed by local concerns. Meanwhile, several towns and cities have begun to explore another possibility: siting wind projects in urban areas. This thesis provides a framework to help readers compare the stories told about wind power in cities to the experiences in rural or "pristine" locations. It asks: 1) What are the motivations for wind power development in the urban context? 2) Does the community and political response to wind power in towns and cities differ from the experience in rural or offshore settings? To answer these questions, I investigated wind energy projects in Hull (Boston, MA region), Toronto (ON), Palmdale (Los Angeles, CA region), and Lackawanna (Buffalo, NY region). Based on a review of existing literature on rural wind siting controversies, I anticipated that local opinions about urban wind power would be formed primarily by expectations about the urban skyline and natural landscape, choice of ownership models, and the extent of meaningful community participation in the planning process. I found that while many of the factors highlighted in research on rural wind siting did affect community acceptance in the four cases, the greater social and spatial complexity of the "local" urban environment created new challenges. I conclude that 1) stories about urban wind power's costs and benefits diverged at the neighborhood scale and city scale;
(cont.) 2) the use of degraded and industrial sites helped in siting turbines, but did not guarantee success due to the multiple interpretations of even these sites; 3) "local" ownership did not necessarily quell controversies over siting; and 4) political dynamics that were largely unrelated to the specific projects strongly influenced communities' receptiveness to proposed wind development. I suggest several strategies to help cities plan for urban wind power initiatives at a larger scale that are equitable and provide meaningful environmental and economic benefits.
by Jonathan S. Cherry.
M.C.P.
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Pinheiro, Juarez Mota. "Clima urbano da cidade de São Luís do Maranhão." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/8/8135/tde-13022019-160256/.
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A cidade de São Luís é a capital do Estado do Maranhão e encontra-se na Região Nordeste do Brasil, seu crescimento urbano tem se mostrado exponencial e isto está afetando diretamente as trocas de energia que determinam o seu clima. Com objetivo de compreender a dinâmica do seu clima urbano e, apoiado nas concepções da interação existente entre a atmosfera e a superfície de morfologia urbanizada, utilizou-se da proposta metodológica Sistema Clima Urbano (SCU), de Monteiro (1975), aplicando todos os canais de percepção dos subsistemas propostos: físico-químico (qualidade do ar), hidrometeórico (impacto meteórico), termodinâmico (conforto térmico), acrescido com a incorporação do vento. Com o uso da metodologia foi possível confirmar os níveis de influência que o vento e a urbanização têm exercido na configuração da dinâmica climática da cidade. A pesquisa chegou a resultados que, além de demonstrar a viabilidade da aplicação metodológica SCU, identificaram que os níveis de poluição atmosférica na cidade de São Luís estão, em grande parte, em patamares aceitáveis, isto é, dentro dos padrões estabelecidos pela Resolução CONAMA 03/90, cuja única exceção é na zona portuária da cidade com baixo impacto de repercussão no restante da cidade. Constatou-se também que a distribuição espaço-temporal das chuvas em São Luís e na Ilha do Maranhão apresenta variabilidade significativa e que os ventos em associação com a urbanização estão influenciando na dinâmica hidrometeorológica determinando volumes de chuvas maiores em parte de sua faixa litorânea e na distribuição espacial que acompanha a direção do vento. Também foi possível concluir que os valores de temperatura do ar, além dos seus níveis de conforto térmico na cidade, estão sofrendo alterações negativas em função da urbanização crescente, com o surgimento de prédios cada vez mais altos, principalmente na orla litorânea da cidade, afetando a penetração dos ventos que são predominantes de direção NE ENE (nordeste lés-nordeste), e que estão influenciando nas diferenças térmicas entre a parte central da cidade e sua faixa litorânea e, por conseguinte, no seu conforto térmico humano que se apresenta muito mais negativo no centro da cidade do que na faixa litorânea. O vento apresentou-se como elemento atmosférico preponderante na dinâmica climática da cidade de São Luís do Maranhão.The city of São Luis is the capital of the state Maranhão and its found at the Northeast Region in Brazil, its urban growth has showed exponential and this is affecting directly the energy exchanges wich affect its weather. With the goal of understand the dynamics of its urban weather and, suported in the conceptions of interrelations between atmosphere surface of urbanized morphology, it was used the methodological proposal Urban Climate System (SCU), by Monteiro (1975), aplying perceptions chanels of the proposed subsystems: physico-chemical (quality of air), hydro-meteoric (meteoric impact), thermodynamic (termic confort), added to the incorporation of the wind . With the use of methedology was possible to confirm the levels of influence that the wind and the urbanizaton have exercise in the configuration of climate dynamics in the city. The search found results that, beyond demonstrate the feasibility of methodological aplication SCU, identify the levels of atmosphereric pollution in the city of São Luís are, in the most, in acceptable levels, that is, inside the settle padrons by resolution CONAMA 03/90, wich the only exception is at the port region in the city with low impact of repercussion in the rest os the city. It was also found that the spatio-temporal distribution of the rains in São Luís and in the island of Maranhão it shows significant viability and the winds in association with the urbanization are influencing in the hydro-meteoric dynamics determining volumes of biggest rains in part of its coastal strip and in the spacial distribution that follow the wind Direction. It was also possible to conclude that the values of air temperature, beyond the levels of termal comfortin the city, are suffering negative alterations in fuction of crescent urbanization, with the appearance of higher buildings, mainly in the coastal strip, affecting the penetration of winds that are predominantly of directions NE-ENE (northeast les-northweast), and that are influencing in thermal differences between the central parto of the city and its coastal strip and, consequently, in its thermal human comfort that present much more negative in the central of city than in the coastal strip. The wind is the atmospheric element preponderant in the clamatic dynamics at the city of São Luís, Maranhão.
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Gough, Matthew Brian. "Assessing the potential for urban wind energy in Cape Town." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/27812.
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As the demand for alternative and renewable sources of energy grows worldwide, it has been argued that small-scale Urban Wind Energy (UWE) could have the potential to provide a significant portion of the electricity demand for urban areas. However there is currently a lack of knowledge surrounding the realisable potential for UWE, especially in the South African context. In order to gain a better understanding of the potential for UWE and the barriers acting against its widespread uptake, it is essential to first quantify the resource potential. This study appraise and evaluate the UWE resource potential at six locations in Cape Town, South Africa in order to gain a solid understanding of the UWE resource potential and thus begin to build the knowledge base around UWE. In order to meet the research objectives, wind data was obtained from the South African Weather Service for six locations in Cape Town at five minute recording intervals for a period of two years. These locations were: The Royal Cape Yacht Club located in the Table Bay harbour, the Astronomical Observatory located in Observatory, and the Kirstenbosch Botanical Gardens located in Kirstenbosch, the Molteno reservoir located in Oranjezicht, the Automatic Weather station located near the Cape Town International Airport as well as the Cape Town Weather Office (WO) station which is also located at the Cape Town International Airport. The data sets are then analysed using a script written in the programming language R in order to quantify the wind energy resource potential of the chosen locations. The wind energy resource potential of each site was combined with four commercially available wind turbines power curves in order to calculate the expected annual energy production values of the various turbines at the each of the locations. Results from this study highlight the significant variability resource potential of the wind regime that occurs between the six locations. The lowest yearly average wind speed was 2.044m/s which was recorded at the Kirstenbosch recording station, while the highest average wind speed was 5.06m/s which was recorded at the WO station. The average of all six stations for the two year period was 3.24m/s. Therefore the WO station had the highest energy potential with a value of 1474 kWh/m²/year and the station with the lowest energy potential was the Kirstenbosch station with a value of 80 kWh/m²/year. Combining these resource potential values with power cures from four commercially available wind turbines yields the Annual Energy Production (AEP) values for the chosen site and wind turbine. These AEP values also varied drastically with the high of 4304 kWh/year being calculated for the SkyStream turbine at the WO station and a low of just 0.66 kWh/year being calculated at the Kirstenbosch station with the Turby turbine. This variability hampers the wide spread uptake of small scale wind power as the results from one area cannot be reliably used to infer the wind resource potential at another nearby site. Out of the six chosen locations in the Cape Town area, three of the locations (Royal Cape Yacht Club, the Automatic Weather Station (AWS), and the Cape Town Weather Office (WO)) showed potential for the installation of a small scale wind turbine, with the Horizontal Axis Wind Turbines (HAWTs) performing better than the Vertical Axis Wind Turbines (VAWTs). This is possibly due to the lower cut in wind speeds of the HAWTs compared to the cut in wind speeds for the VAWTs. The conclusions of this study show that the UWE resource potential in Cape Town is characterised by high resource variability between the various locations. Three of the six locations that were evaluated showed potential for UWE installations. This study has identified the major challenges associated with UWE to be the turbulence, lower hub heights of the wind turbines (this study used 20m as the standard hub height), and variability of the wind regime between locations.
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Wo, Chung. "PERFORMANCE ASSESSMENT OF THE CASE WESTERN RESERVE UNIVERSITYWIND TURBINE AND CHARACTERIZATION OF WIND AVAILABILITY." Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1383338732.
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Bassett, Richard. "Quantifying the influence of wind advection on the urban heat island." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8411/.
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Although the urban heat island (UHI) is well studied, the dynamic nature (i.e. with wind) receives little attention. The concept, urban heat advection (UHA), can warm air temperatures in surrounding rural areas. This may lead to a misinterpretation of local climate and bias in long-term climate records. Using observational analysis and numerical modelling this thesis investigates these limitations by spatially quantifying UHA. A methodology to separate UHA from the background air temperature was applied to a high-density urban observation network in the city of Birmingham, UK demonstrating mean downwind UHA of 0.4oC and up to 1.2oC at individual stations (wind speeds 2 – 3 m s-1). This UHA methodology was adapted to show that even small urban areas (~1 km2) can produce a mean UHA of 0.6oC. TheWeather Research & Forecasting numerical model was used to refine the UHA methodology (accounting for regional heat advection) and conduct semiidealised simulations. Here, a square city with 16 km size produced UHA of 2.4oC at the city edge, with 0.5oC warming extending 9 km downwind. A relationship was found between city size and UHA intensity, enabling statistical scaling. This demonstrated an approach to estimate UHA without the need for computationally expensive simulations.
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Xuan, Wei. "Wind-induced dispersion of building exhaust in an urban environment : a full-scale and wind-tunnel study." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ39097.pdf.
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Scaperdas, Athena-Sophia. "Modelling air flow and pollutant dispersion at urban canyon intersections." Thesis, Imperial College London, 2000. http://hdl.handle.net/10044/1/8803.
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Zhang, Mimi Q. "Feasibility analysis of coordinated offshore wind project development in the U.S." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45762.
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Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2008.Includes bibliographical references (p. 53-62).
Wind energy is one of the cleanest and most available resources in the world, and advancements in wind technology are making it more cost effective. Though wind power is rapidly developing in many regions, its variable nature creates obstacles in integrating significant amounts of wind power to the electric grid. One potential solution for reducing the fluctuating nature of wind power is to site wind projects in regions of complementing wind regimes to reduce variability. This thesis explores the feasibility of creating a coordinated network of offshore wind projects through examining its technological requirements, economic viability, and the policy and planning issues of building such a network in the U.S. Wind speed data for sites along the east coast of the U.S. are used to analyze the nature of offshore wind patterns and the benefits of interconnecting multiple wind projects. The main questions are: 1) Is an offshore wind network technologically feasible? 2) What are the costs and benefits of creating an offshore network with transmission lines? 3) What are potential ways to plan, permit, and develop such a network? An overview of research on existing turbine technology, turbine foundation technology, and transmission technology show that it is technically possible to build a network of offshore wind projects. An analysis of the costs and benefits of physical interconnection show that the cost savings from reduced variability pale in comparison to interconnection costs. It is more cost effective to coordinate the siting of all projects within the network, by connect the projects directly to the onshore grid as opposed to creating a separate, offshore grid for wind projects. The current planning process for offshore wind development permits projects on a site-by-site basis, so developing an entire network of sites with the goal of reducing variability would require an extensive stakeholder process where all relevant parties agree on a set of sites. A coordinated network could also be developed over time by incorporating variability as a priority in the permitting process.
by Mimi Q. Zhang.
M.C.P.
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Liu, Hongliang. "Contribution for integrating urban wind turbine into electrical microgrid : modeling and control." Thesis, Compiègne, 2017. http://www.theses.fr/2017COMP2331/document.
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L’intégration de l’énergie éolienne, qui est une ressource renouvelable très utilisée, n’est pas toujours facile pour le micro-réseau urbain. Dans cette thèse, une éolienne urbaine basée sur une machine synchrone à aimants permanents (MSAP) est étudiée pour être intégrée dans un micro-réseau urbain à courant continu. Un état de l'art concernant les énergies renouvelables, les micro-réseaux à courant continu et les stratégies de contrôle de la production d'énergie éolienne, est réalisée. Basé sur un modèle d’éolienne urbaine répondant à la demande du système électrique, qui se compose d’un émulateur de vent et de pales, un MSAP et un convertisseur DC/DC, cette thèse propose des méthodes de poursuite du point de puissance maximale satisfaisant à l’obligation de produire de l’énergie dans la mesure du possible. Une stratégie de contrôle à puissance limitée répond correctement. De simples à complexes, quatre algorithmes MPPT, P&O à pas fixe, P&O à pas variable avec la méthode Newton-Raphson améliorée, P&O à pas variable à base de logique floue et une méthode indirecte de type lookup table, sont étudiés et implémentés pour être comparés à l’aide de trois profils de vitesse du vent. Par expérimentation, les algorithmes MPPT et PLC sont comparés, analysés et discutés. Résumant tous les résultats expérimentaux, la méthode lookup table peut gérer toutes les exigences du mode de fonctionnement MPPT en présentant la meilleure performance, mais, dans le mode de fonctionnement PLC, la P&O à base de logique floue présente les meilleures performancesThe integration of the wind power, which is one mostly used renewable resource, is always one challenger for urban microgrid. In this thesis, one urban wind turbine based on a permanent magnet synchronous machine (PMSM) is studied in order to be integrated into a DC urban microgrid. A state of the art concerning the renewable energies, DC microgrid, and control strategies of wind power generation is done. Based on a model of urban wind turbine fitting the demand of urban electric system, which consists of an emulator of wind speed and blades, a PMSM and a DC/DC converter, this thesis proposes the maximum power point tracking (MPPT) methods satisfying the requirement of producing energy as much as possible, and power limited control (PLC) strategies answering the demand of flexible energy production. From simple to complex, four MPPT algorithms including Perturbation and Observation (P&O) fixed step-size method, P&O with improved Newton-Raphson method, P&O with fuzzy logic method and lookup table method are studied and implemented to be compared with each other using three wind velocity profiles. According to the experience about MPPT subject, four PLC algorithms are introduced and implemented to be analyzed and compared with each other with one power demand profile calculated randomly. Summarizing all experimental results, the lookup table method can handle all requirement of MPPT operating mode supplying the best performance, however, in the condition of more flexible power demand operating mode, the combination of P&O and fuzzy logic method presents the best performance and potential which can be achieved in future works
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Awan, Muhammad Rizwan. "Feasibility Study of Vertical Axis wind turbines in Urban areas of Sweden." Thesis, KTH, Kraft- och värmeteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-129410.
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Yifan, Wang, and Huang Yizhang. "Urban Wind and Thermal Environment Simulation - A Case Study of Gävle, Sweden." Thesis, Högskolan i Gävle, Avdelningen för Industriell utveckling, IT och Samhällsbyggnad, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-16605.
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As urbanization and industrialization progressed during the last decades, Urban Heat Island (UHI) has become a major environmental issue to many cities around the world. The effect of UHI differs from area to area due to varying urban scale, population density, construction of urban surface layer, the level of industrialization and type of climate. Researchers have made great efforts in investigating various approaches to Urban Heat Island studies. Monitoring technologies have been widely used in this field, especially Geographic Information System (GIS) and remote sensing technology. Computational Fluid Dynamics (CFD) simulations are also actively applied in wind engineering, which can provide details of air flow over urban areas. The combined application of these technologies can provide the monitoring and simulation of urban wind corridor and thermal environment that can produce relevant information at a lesser time.A research using GIS, remote sensing technology and CFD simulation was done in this project to obtain a holistic view of the urban thermal environment and wind flow for Gävle City. With GIS and remote sensing the thermal image of the city was presented. The temperature data, which were collected from MODIS satellite were transferred and processed by ArcGIS and Global Mapper. The wind flow above the city was simulated through constructing geometric and mathematical model with OpenFOAM. The outcomes of the modeling and simulation identified that the temperature in the city center could possibly reach 35℃ during summers, which can cause the Urban Heat Island to form. Ventilation was also poorer in the city centre, and neither the river nor the green area in the southwest could help ventilate the city. The study result also suggested that certain sites in the city had relatively high wind flow for urban wind turbines to work.This study had used method of Urban Heat Island study with remote sensing and CFD technologies. The model produced from simulation could also be used to further study Gävle city's thermal and wind environment to produce more accurate results.
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Kinzer, Kirsten (Kirsten Lee). "Building green infrastructure through urban land conservation : the social and ecological value of dispersed open space in the Boston urban wilds." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37866.
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Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2006.Includes bibliographical references (p. 118-123).
Through an analysis of the thirty-year history of the Boston Urban Wilds, this thesis investigates the ability of distributed urban open spaces to provide social and ecological value to the surrounding community. The capacity of the Urban Wilds to act as system to provide simultaneously ecosystem services, public space and wildlife habitat is examined. The evolving understanding of green infrastructure is used as a lens through which to understand the elements of the Urban Wilds model applicable to other communities. Through this lens, the ability of the Urban Wilds to provide social and ecological value greater than the sum of its individual parts is considered. Reflecting on the tools that have been used to enact Urban Wilds conservation, the tools best suited to preserving the Urban Wilds' social and ecological value are assessed. Drawing from the evolution of the Boston Urban Wilds over the past three decades, this thesis concludes with designation, preservation and stewardship recommendations for other cities and towns considering a similar system of distributed open spaces.
by Kirsten Kinzer.
M.C.P.
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Hsie, Tung-Shen. "Utilising climate maps in the planning process : a GIS-based approach to urban morphology parameterisation and urban wind environment studies." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.549494.
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Wang, Jialin. "Building integrated wind energy." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/building-integrated-wind-energy(81978798-e68a-4189-87b0-4159b280b6e9).html.
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In considering methods of reducing the emission of carbon dioxide; there is a growing interest for use of wind power at domestic building in U.K. But the technology of wind turbines development in building environment is more complicated than in open areas. Small wind turbines in suburban areas have been reported as having unsatisfactory energy output, but it is not clear whether this is due to insufficient wind resource or low turbine efficiency. The aim of this research is to discover whether the wind resource in suburban areas is large enough for small wind turbines to produce a useful energy output.Historical wind data and manufacturers' turbine characteristics were used to estimate the hourly wind speed and energy output for different U.K. cities, terrain zones and turbines. It was found that for turbines at 10 m height in suburban areas and depending on city, the annual wind energy conversion efficiency ranged from about 20 to 40%, while the number of turbines required to produce the annual average electricity consumption of a UK dwelling ranged from about 6 for the smallest turbine (5.3 m² rotor area) to about 1 for the largest (35.26 m² rotor area).This analysis was based on average conditions, but the wind speed near buildings can vary considerably from one point to another. In order to predict the performance of wind turbines more accurately, the atmospheric boundary layer (ABL) of suburban areas was simulated in both CFD and wind tunnel models, and models of groups of semi-detached and terraced houses were set in this ABL. It was found that at 10 m height in the area of the houses, the turbulence intensity was too high for satisfactory operation of wind turbines (19 to 35%) while the mean velocity at different points ranged from 86 to 108% of the 10m reference velocity. At 30m height the turbulence intensity was satisfactory (less than 19 %), while the mean velocity ranged from 92 to 103 % of the 30 m reference velocity. It is concluded that for wind turbines in suburban areas, at 10 m height the wind speed is too low and the turbulence is too high for satisfactory performance, while at 30 m height the wind speed is much higher and the turbulence is low enough.
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夏激揚 and Jiyang Xia. "Numerical study on wind field and air pollutant dispersion in urban street canopies." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31242509.
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Park, Kyooseon. "Optimal design of a micro vertical axis wind turbine for sustainable urban environment." Thesis, University of Huddersfield, 2013. http://eprints.hud.ac.uk/id/eprint/19032/.
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The need for sustainable energy sources becomes greater each year due to the continued depletion of fossil fuels and the resulting energy crisis. Solutions to this problem are potentially in the form of wind turbines, for sustainable urban environment, that have been receiving increased support. At present, a number of wind turbines have been developed that show significant increase in performance compared to existing technologies. From an extensive literature review, a number of key issues have been highlighted which are concerned with the design, optimisation and diagnostics of Vertical Axis Wind Turbines (VAWTs) that have been used to formulate the scope of this research. A design procedure for a vertical axis wind turbine, that features both multi-blade rotor and fixed outer stator guide vanes, has been derived, in which both rotor and stator blade profiles have been generated for a low wind speed application. In the presented work, numerical investigations have been carried out extensively to determine the optimised design of the VAWT. Sliding mesh technique has been used for the rotation of rotor blades. This new technique captures the transient flow phenomena that occur when the rotor and the stator blades interact with each other. Hence, the results predicted by CFD using this technique are much superior in accuracy. Furthermore, a detailed flow field analysis of the VAWT has highlighted large asymmetries in both pressure and flow velocity about the central axis of the VAWT in both the stationary and the rotating frames of references. Various geometric parameters associated with the design of the VAWT have been investigated over a wide range in order to analyse the effect of these parameters on the performance output of the VAWT. These geometric parameters are the blade angles, the number of blades in the VAWT and the size of the rotor/stator sections of the VAWT. It has been shown that all these parameters considerably affect the performance output of the VAWT and hence have been optimised in the present study for maximum performance output of the VAWT. One of the key elements of this study is the development of a performance prediction model of the VAWT that takes into account the effects of the aforementioned geometric parameters of the VAWT. This novel prediction model is both robust, user-friendly and has shown to predict the performance output of the VAWT with reasonable accuracy. Hence, the prediction model can be used by the designers of the VAWT. Nowadays, condition based health monitoring of mechanical systems is topic of vast research. Most of the studies in this field use experimental facilities and conventional toolboxes to handle the output data from the sensors. With the advent of advanced CFD tools, it has now become possible to use CFD as an effective tool for fault detection in VAWTs. An attempt has been presented in this study regarding condition monitoring of VAWTs for sustainable urban environment. Various faults like missing blade and slits in blade have been investigated and analysed. It has been shown that CFD can detect these faults and show the effects of these faults on local flow parameters such as pressure and velocity.
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Pogulis, Markus. "Algebraic multigrid for a mass-consistent wind model, the Nordic Urban Dispersion model." Thesis, Umeå universitet, Institutionen för fysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-105499.
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In preparation for, and for decision support during, CBRN (chemical, biological, radiological and nuclear) emergencies it is essential to know how such an event would turn out, so that one can prepare a possible evacuation. Afterwards it might be good to know how to backtrack and see what caused the emergency, and in the case of e.g. a gas leak, where did it begin? The Swedish Defence Research Agency (FOI) develops models for such scenarios. In this thesis FOI's model, "The Nordic Urban Dispersion model" (NUD), has been studied. The system of equations set up by this model was originally solved using Intel's PARDISO solver, which is a direct solver. An evaluation on how an iterative multigrid method would work to solve the system has been done in this thesis. The wind model is a mass-consistent model which sets up a diagnostic initial wind field. The final wind field is later minimized under the constraint of the continuity equation. The minimization problem is solved using Lagrange multipliers and the system turns into a Poisson-like problem. The iterative algebraic multigrid solver (AMG) which has been evaluated had difficulties solving the problem of an asymmetric system matrix generated by NUD. The AMG solver was then tried on a symmetric discrete Poisson problem instead, and the solution turns out to be the same as for the PARDISO solver. A comparison was made between the AMG and PARDISO solver, and for the discrete Poisson case the AMG solver turned out on top for both larger system size and less computational time. To try out the solvers for the original NUD case a modification of the boundary conditions was made to make the system matrix symmetric. This modification turns the problem into a mathematical problem rather than a physical one, as the wind fields generated are not physically correct. For this modified case both the solvers get the same solution in essentially the same computational time. A method of how to in the future solve the original (asymmetric) problem, by modifying the discretization of the boundary conditions, has been discussed.
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Ferrigno, Kevin J. (Kevin James). "Challenges and strategies for increasing adoption of small wind turbines in urban areas." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59240.
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Thesis (S.M. in System Design and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, June 2010."May 2010." Cataloged from PDF version of thesis.
Includes bibliographical references (p. 77-80).
A student group at MIT in cooperation with the MIT Department of Facilities is currently working to install a Skystream 3.7 wind turbine on MIT's campus. This has raised several questions about how to best develop small wind projects in urban environments. The best wind resources in the country exist in relatively remote locations and require large investments in electricity transmission infrastructure to be effectively utilized. In the meantime, several large and small projects have been developed in the Boston area. The urban environment presents many challenges to development including the interaction of urban buildings with wind flow, concerns from neighbors and government over the aesthetics and safety of turbines that are installed near human populations, environmental effects including wildlife, noise, and shadows. There are also many opportunities including the ability to use net metering, little or no transmission infrastructure costs, and the ability to build on existing wind resource data and project assessments to develop a large number of installations. This document presents an overview of how the challenges of small wind turbine development in urban, suburban, and rural neighborhoods are currently being addressed by research in new and improved technology for turbines and siting, business strategies of existing companies, financing, and government policy. It looks at the strategy options available to businesses involved development of small wind turbines and evaluates the relative strengths and weaknesses of these strategies in a rapidly changing marketplace.
by Kevin Ferrigno.
S.M.in System Design and Management
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Zhang, Xu. "Analysis and optimisation of a novel wind turbine." Thesis, University of Hertfordshire, 2014. http://hdl.handle.net/2299/13897.
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The technologies of urban wind turbines have been rapidly developed in recent years, but urban wind turbines have not found a wide application due to the limitations of their designs. The power output of urban wind turbine is significantly affected by urban terrain, which can cause low speed flow with frequent change of its direction. Thus, there is a need for a new wind turbine to meet the requirements of an urban wind turbine. In this study, a novel wind turbine for urban areas was designed and developed. The investigations of the novel urban wind turbine were carried out by using computational fluid dynamic (CFD) simulations and wind tunnel tests. The results from the investigation have shown that the novel wind turbine has a great potential to harvest wind energy in urban areas. A detailed study of effects of each parameter on wind energy concentration of the novel wind turbine was carried out with CFD simulations. According to the simulation results, the shroud structure of the novel wind turbine was modified and the dimensions of the final structure were identified. It was determined that the capability of wind energy concentration of the novel wind turbine shroud has been significantly improved through the structure optimisations. Furthermore, guide vane and impulse turbine were implemented in the novel wind turbine. The flow characteristics through the guide vane was studied and discussed. It was found that the wind flow characteristics can be properly modified by implementing guide vane and the structure of impulse turbine was suitable to be implemented in the novel wind turbine due to the flow characteristic through the guide vane.
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Yu, Yichen. "Thermal respite for pedestrians in overheated urban environments." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/24302.
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The sedentary lifestyle prevalent in most developed countries can have serious impacts on health, increasing the risk of cardiovascular disease, diabetes and obesity. In response, public health campaigns routinely exhort communities to spend more time engaged in outdoor activities. However, in warm-to-hot climate zones where the rate of urbanisation is greatest, the urban heat island effect negatively impacts on the appeal of outdoor activities involving parks and active modes of transport such as walking or cycling to everyday destinations. Previous studies have indicated that even on hot summer days in subtropical cities such as Sydney, outdoor thermal comfort is attainable through various cooling strategies, such as introducing vegetation and water bodies; coating buildings and streets with cooling materials; and adjusting building and urban precinct morphology to minimise the accumulation of unwanted heat. To reduce urban thermal discomfort and maximise walkability, city managers and urban designers have optimised the location and operational characteristics of outdoor thermal comfort respite (cooling infrastructure) through the application of thermal comfort models. Such models predict thermal perceptions under historical norms for meteorological conditions, but results to date have been less than satisfactory. Most of the comfort models applied to this problem are premised on steady-state conditions, which is clearly inappropriate for pedestrians who have to negotiate a series of diverse, short-term, micro-environmental exposures, both indoors and out, in the course of their day-to-day activities. Contributing to the disappointing predictive ability of outdoor comfort models is the fact that the cooling effect of wind has been inadequately parameterised. Urbanisation amplifies the morphological complexity of the terrain, increasing roughness length within the atmospheric surface layer, which introduces highly turbulent wind flow at pedestrian height. However, little is known about turbulence conditions inside cities, and even less is known about its effect on the thermal comfort of pedestrians. In this study, the wind environment inside a city was measured in a variety of urban settings using sonic anemometry to characterise urban atmospheric turbulence. Those observed turbulent conditions were then reproduced in a wind tunnel using a passive grid system. A full-sized thermal manikin was used to measure convective heat transfer coefficients. Physical analyses were supplemented with human subject experiments in which physiological and psychological responses to those turbulent wind tunnel exposures were captured. Results confirm that increasing turbulence intensity enhances perceived coolness by reducing skin temperature. Ignoring turbulence causes the impact of wind on a person’s mean skin temperature decrement to be underestimated by 30% and 50% in standing and cycling postures respectively. The convective heat transfer coefficients in a numerical skin thermoreceptor model and a human thermal physiology model were adjusted to more accurately represent the effects of turbulent wind conditions. How can predicted human thermal response be used to characterise short-term, transient exposures to complex and diverse urban microclimates? When citizens are walking outdoors on a hot summer day, for how long can they tolerate heat discomfort? To identify this discomfort threshold, a sample of human subjects was exposed to simulated urban heat stress at various radiation intensities inside a wind tunnel while cycling on an ergometer to simulate the metabolic rate of a brisk walk. The discomfort accruing from sustained exercise in heat was conceptualised as an electrical capacitor. Thermal respite discharges the discomfort capacitor. In the wind tunnel experiments, respite was presented — as wind, shade and a combination of the two — to individual subjects while they self-reported thermal discomfort intensity. Though each subject had his or her own “thermal comfort personality,” for most subjects in this experiment, the cumulative heat load needed to be discharged before mean body temperature change exceeded ∆0.4 ℃. This typically occurs around 4 minutes after walking outdoors on a sunny day in summer at an operative temperature of about 36℃. The concept of ‘discomfort degree minutes’ is proposed to represent the accumulated thermal load on a pedestrian. It can indicate the real-time thermal discomfort experienced by someone traversing a patchwork of urban microclimates. It can also be used to optimise the placement or spacing of thermal respite for any combination of internal metabolic and external environmental heat loads on the person. For example, pedestrians walking at ~6 k/hr in an operative temperature of ~36oC, unshaded street exposures should not exceed 400 m, particularly when wind resources within the urban canyon are unreliable. Thermal respite in this urban planning scenario could take the form of wind (natural or mechanically generated) lasting more than 90 seconds, or a 250 m stretch of shade, or any other mode of outdoor cooling capable of effecting a 1.3 degree-minute discharge of the pedestrian’s mean skin temperature. This study provides a deeper understanding of the pedestrian level wind environment inside the city and illustrates the effects of turbulence on thermal perception. Pedestrians’ subjective tolerance of urban heat is quantified, and strategies for discharging the ‘heat discomfort capacitor’ with wind and/or shade are proposed. The research can help to optimise the design and delivery of outdoor cooling resources that improve the usability of urban spaces in warm-to-hot climates/seasons. Human-centred design of urban space can increase levels of community participation in outdoor activities and ultimately reduce the burden of disease resulting from excessively sedentary indoor lifestyles.
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Traldi, Mariana 1984. "Novos usos do território no semiárido nordestino : implantação de parques eólicos e valorização seletiva nos municípios de Caetité (BA) e João Câmara (RN)." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/286604.
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Orientador: Márcio Antonio CataiaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências
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Resumo: Desde 2004 no Brasil tem havido uma crescente expansão da instalação de parques eólicos para geração de energia elétrica. No Brasil a fonte hegemônica na produção de energia elétrica sempre foi à hídrica. Contudo, a partir da crise do Apagão de 2001, que resultou no déficit na oferta de energia no macrossistema elétrico brasileiro o Estado tem buscado aumentar a oferta de energia elétrica através da diversificação da matriz elétrica nacional. Entre as fontes que vem ganhando importância está a fonte eólica. Desta forma, apresentamos nesta dissertação um panorama dos novos usos do território que resultam da instalação dos parques eólicos nos municípios de João Câmara (RN) e Caetité (BA), localizados no semiárido brasileiro. Buscamos desmistificar afirmações que sustentam serem os parques eólicos promotores do desenvolvimento local e grandes vetores de incremento na arrecadação de tributos municipais e estaduais. Identificamos assim os nexos entre a instalação dos parques eólicos e as necessidades impostas aos lugares pelo macrossistema elétrico brasileiro
Abstract: Although, the hegemonic power in the production of electricity has always been hydroeletric, since 2004 has been an increasing expansion of the installation of wind farms for power generation. The crisis known as Blackout 2001 resulted in a deficit of energy supply in the Brazilian large technological system. As a solution the Brazilian state has decided to increase the supply of electricity through the diversification of the national energy matrix. Among the sources that is gaining importance is wind power. Thus, we present in this paper an overview of the new uses of the territory resulting from the installation of wind farms in João Câmara (RN) and Caetité (BA) located in the Brazilian semiarid region. We seek to debunk claims that support wind farms being promoters of local development and large increment vectors in the collection of state and local taxes. Thus identify the links between the installation of wind farms and the needs imposed by the Brazilian technological large system
Mestrado
Análise Ambiental e Dinâmica Territorial
Mestra em Geografia
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Raymond, Brent A. "The effect of urban open spaces on winter wind speed in residential Guelph, Ontario." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ51090.pdf.
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So, Shuk-pan Ellen, and 蘇淑彬. "Large eddy simulations of wind flow and pollution dispersion in an urban street canyon." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29332710.
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Øvereng, Aurora. "A Sustainable Future for Wind Energy in Sweden." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-166394.
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The 2040 governmental goal of 100 % renewable electricity in Sweden means that there will be a shift in electricity production and a phasing out of nuclear power. This nuclear power has to be replaced by some other source. Wind power is a viable alternative, thanks to its reliability and the abundance of wind in Sweden. However, wind power production requires a large amount of land and carries the risk of disrupting the landscape. Wind energy is therefore often difficult to develop, and when developed it is often in rural areas where it disturbs as few people as possible. This study presents an alternative to rural exploitation, it investigates whether it is possible to produce sufficient wind power to satisfy urban demand within 20 000 meters of the 20 largest cities in Sweden. Firstly, the criteria for areas where wind power can be developed were synthesised. Secondly a numerical model was used to simulate energy demand in TWh considering the future growth in demand and the phasing out of nuclear power. The demand for wind power was then translated into correlating area in km2. Finally, a GIS analysis was conducted to estimate the extent of area suitable for wind power development based on the criteria above and within a 20 000m perimeter from the 20 largest cities in Sweden. The analysis showed that only 35 % of the required area for wind power development fulfilled the criteria within the given perimeter. From the GIS analysis only 940.73 km2 was found to be suitable. From the numerical model, the results showed that for it to be sufficient, there would have to be at least 2687.1 km2 suitable land. The conclusion from this study is that in order to phase out the nuclear power, the majority of the wind power has to be located in the rural areas.
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Luo, Zhiwen, and 罗志文. "City ventilation by slope wind." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B46089962.
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Upchurch, Meredith. "Green Infrastructure: The Landscape of Urban EcoHousing." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/32859.
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Cities are facing environmental crises like never before, with problems of excess water runoff, degraded water quality, air pollution, and energy use reaching critical levels. The development of urban areas and the built environment is the primary cause of these problems and the built environment needs to be a part of the solution. This design thesis project produces a prototype design for the Urban EcoHousing development on a city block in Alexandria, Virginia. Design goals for the project connect the â Ecological Services of the Urban Landscapeâ to the â Rights of the Urban EcoHousing Residentâ to create livable green spaces that can serve ecological functions and give the residents spaces to use. A comparison study with a conventional housing development at the same location illustrates that ecohousing can meet the requirements of the conventional development while providing superior results for the residents and the environment.Master of Landscape Architecture
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Gebrelibanos, Kalekirstos Gebremariam. "Feasibility Study of Small Scale Standalone Wind Turbine for Urban Area : Case study: KTH Main Campus." Thesis, KTH, Kraft- och värmeteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-129600.
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The recent worldwide economic crisis, climate change and global warming have emphasized that the need for low carbon emissions while also ensuring the economic feasibility. In this paper, wind power potential of ETD in KTH was investigated. The technical and economical feasibility of tower mounted small scale standalone wind turbine installation is conducted. The potential of wind power production was statistically analysed. The average wind speed data of four-season interval of one year period (2011) which its measurement was taken on the roof top of the ETDB, and this was adopted and analysed in order to find out the potential of wind power generation. The Rayleigh distribution probability was applied to calculate the wind speed distribution at KTH, by doing so the annual wind power potential at the area and annual energy production of the chosen wind turbine was estimated, after the selection of a proper wind turbine have been made upon the site conditions. Therefore, the study result shows that installation of the wind turbine at 24 meters hub height for this particular area will have a better performance of annual energy production, capacity factor, carbon savings and better economical value than the current turbine installed at 17 meters height at the ETD. The economic evaluation shows that the turbine can save an electricity bill of US$3661.05 per year and cover 1.84% of the electricity consumption of the ETD by reducing its respective CO2 emission from the electricity use at the department. Moreover, the payback period of the turbine installation with the inclusion of the green certificate is approximately 14 years which is more feasible if it is considered for small wind turbines too, which is already in practice for renewables including wind power in Sweden.
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Peregrino, Paulo Sergio Araújo. "Interrelações existentes entre os escoamentos de ventos e os padrões de ocupação do solo nos bairros do Cabo Branco e Tambaú/João pessoa - PB." Universidade Federal da Paraíba, 2005. http://tede.biblioteca.ufpb.br:8080/handle/tede/5540.
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This research aimed to evaluate how four patterns of the urban use and occupation are interrelated in the wind flow comportment, relating to different settings which were considered in: the actual occupation pattern of the areas of Cabo Branco and Tambaú in Joao Pessoa, the capital city of Paraíba State, in the same area, where the three other types were suggested and carried out, the first one relating to the actual legislation considering heavy urban density and the second other two have investigated the possibility of vertical structure for such density. By applying reduced scale modeling experiments in aerodynamic tunnels and by using the erosion figure technique (of sand) (JANEIRO and SARAIVA, 1980), with the methodology developed by Silva (1999), analysis have reached the conclusion that the legal standard induced by the actual legislation may giving permission for irreversible loss in the urban improvement and environmental quality associated to buildings around the beach areas of the whole city in the near future.
O presente trabalho avalia de que forma o escoamento dos ventos se interrelaciona com os quatro padrões de ocupação do solo urbano estudados: o padrão de ocupação atual de parte dos bairros do Cabo Branco e Tambaú/João Pessoa PB, e outros três sugeridos para a mesma área. Entre os modelos expostos, um refere-se ao adensamento da área segundo a legislação vigente, e os outros dois são relativos a outras possibilidades de adensamento vertical. Os modelos em escala reduzida, foram avaliados com base em ensaios efetuados em túnel aerodinâmico, utilizando-se da técnica de figuras de erosão de areia (JANEIRO e SARAIVA, 1980), e metodologia desenvolvida por Silva (1999), concluindo-se que os padrões induzidos pela legislação vigente poderão causar danos irreversíveis à orla da cidade de João Pessoa num futuro próximo.
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Abohela, Islam Mohamed Mahmoud Mohamed. "Effect of roof shape, wind direction, building height and urban configuration on the energy yield and positioning of roof mounted wind turbines." Thesis, University of Newcastle Upon Tyne, 2012. http://hdl.handle.net/10443/1686.
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The increasing interest among architects and planners in designing environmentally friendly buildings has led to a desire to explore and integrate renewable sources of energy within the built environment. Roof mounted wind turbines is a technology that presents a high potential for integration within the built environment. However, there is a state of uncertainty regarding the viability of these wind turbines. This thesis argues that part of this uncertainty is attributed to uninformed decisions about positioning and locating urban wind turbines. This is underpinned by lack of consideration to the wind accelerating effect of different roof shapes, buildings’ heights and surrounding urban configurations. This thesis aims to investigate the effect of different roof shapes on wind acceleration and positioning of roof mounted wind turbines covering different buildings’ heights within different urban configurations under different wind directions. To achieve the aim of the thesis, the commercial Computational Fluid Dynamics (CFD) code Fluent 12.1, implementing the Realizable k-ε turbulence model, is used to simulate wind flow around different roof shapes, different buildings’ heights and different urban settings. Predictions are comparatively analysed to identify the optimum roof shape for mounting wind turbines. Simulation results indicate that the barrel vaulted roof has the highest wind accelerating effect. The barrel vaulted roof shape case was carried further to investigate the effect of building height and surrounding urban configurations on the energy yield and positioning of roof mounted wind turbines. The optimum mounting location for each of the investigated roof shapes namely: flat, domed, gabled, pyramidal, barrel vaulted and wedged roofs is identified. Results from the investigation predict a possible increase up to 56.1% in energy yield in the case of a barrel vaulted roof if an informed wind assessment above buildings’ roofs is carried out. However, changing the building height and surrounding urban configuration had an effect on choosing the optimum mounting location and the energy yield at that location.
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Emejeamara, Francis Chimeziri. "Urban wind resource assessment : predicting the turbulence intensity, excess energy available and performance of roof mounted wind turbines in a built environments." Thesis, University of Leeds, 2017. http://etheses.whiterose.ac.uk/17496/.
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De-centralised renewable energy power generation is proposed to be a significant part of the future of electricity generation technology, with wind energy playing a significant role. With half of the global population residing in urban and suburban areas, the opportunity for individuals or small organisations to generate power locally facilitates the decrease in losses associated with long distance electricity generation and transmission. Small-scale wind turbine applications within suburban/urban areas are exposed to high level of gust and turbulence compared to flow over less rough surfaces (e.g. coastal/offshore areas, open grasslands, rural areas, etc.). There is, therefore, a need for such systems not only to cope with, but to thrive under such rapidly fluctuating, complex urban wind conditions. Assessing the potential of a proposed urban wind turbine project is hindered by insufficient assessment of both the urban wind resource and power capabilities of certain turbine designs within a potential suburban/urban site. This, however, requires estimation of important factors such as local atmospheric turbulence, total energy available to the turbine system and the potential power output to be generated should a certain turbine system design be installed within a potential site. The research presented in this thesis proposes a methodology for scoping the potential of small wind turbines within a built environment through effective assessment of the urban wind resource and power capabilities of small turbine systems. The aim is to address the lack of accurate and affordable methods for site viability assessment of small wind turbines within a built environment. This methodology encompasses three sub-models which estimate the local atmospheric turbulence (represented by the turbulence intensity, T.I.), additional energy within the gusty urban wind (represented by the excess energy content, EEC) and the turbine power capability at different heights within a potential site. Firstly, to quantify the influence of location on the total energy available to a small wind turbine at a potential site, an in-depth evaluation of the urban wind resource is completed. This includes the development of methods to predict the local atmospheric turbulence at a given turbine mast height, and the additional energy available to the turbine which is usually under represented when using assessments based only on mean wind speeds. This is achieved using high temporal resolution wind measurement datasets from eight potential turbine sites within the urban and suburban environments and LiDAR building height datasets from three major UK cities namely, Leeds, Manchester and London. Subsequently, new analytical models are developed that allow the mapping of atmospheric turbulence and excess energy at different heights over Leeds, Edinburgh, Manchester and London by combining the T.I. and EEC estimation models with currently available methods of predicting mean wind speeds over urban areas. The results from these two models highlight the importance of including building height variation and changes in wind direction within the assessment, and also the value of employing detailed building geometric data as model inputs. A simple low-cost 2-D multiple streamtube vertical axis wind turbine (VAWT) model capable of simulating turbine performance in a fluctuating wind isdeveloped. Combining this VAWT model with dynamic stall features and variable speed control strategy, enables a system based design of wind turbines operating within suburban/urban environment. A method of estimating the performance of a turbine operation within an urban wind resource is developed by assessing the power capabilities of the VAWT model using high-resolution wind measurement datasets as model inputs. This is combined with the T.I. and EEC estimation models in developing a new model known as the turbine power estimation (TPE) model used in mapping turbine performance at different heights over Leeds, Edinburgh, Manchester and London. Comparison between the TPE model and a generic power curve is made, hence suggesting the possibility of using a simple model to estimate the power capabilities of a certain turbine design while accounting for local turbulence within an urban wind resource. Finally, the investigation of the cumulative potential of small wind turbine power generation in Leeds, Edinburgh, Manchester and London indicates a largely untapped wind resource available (represented by high EEC values estimated within small distances in each city) which could be harnessed if gust tracking solutions were to be commercially available. It also highlights the importance of site viability assessment and its financial implications illustrated by capacity factor maps over the four cities, which has practical value for turbine manufacturers and urban planners alike. Thus, for urban wind applications to achieve their optimum deployment potential, this research study proposes a simple, effective and affordable tool for preliminary scoping the potential of certain small wind turbine designs within a suburban/urban environment, and hence encouraging effective carbon savings. In order to maximize the impact of this research study, it would be valuable that these maps be extended to other towns/cities and made available and easily accessible to individuals and interested parties, and hence this is a major objective of future work.
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Zou, Jiwei. "Predicting convective heat transfer from Computational Thermal Manikin in urban outdoor environments." Thesis, University of Sydney, 2021. https://hdl.handle.net/2123/24516.
Full textAbstract:
Urban residents are increasingly encouraged to go outside for recreation and relaxation purposes, which may improve personal health and reduce building energy consumption. It is important to understand the thermal conditions of human body in urban outdoor environments. However, the urban wind conditions at the pedestrian level and their impact on the thermal comfort of people have not been thoroughly investigated to date.
This study aims to predict the convective heat loss from human body subject to urban outdoor wind environments. Onsite wind measurements are carried out at 0.6 m, 1.2 m, and 1.8 m above the ground on three representative green lands in the coastal city of Sydney in Australia. Meanwhile, the effects of the wind velocity and turbulent conditions on the convective heat loss from human body are investigated using a computational thermal manikin (CTM) model, which is validated against published experimental data. Along with empirical equations derived from the CTM simulation, the wind data collected from onsite measurements is used for predicting the convective heat loss from human body in the outdoor wind environments.
In total six groups of wind measurements have been carried out at each measurement sites over a period of four months (from March 2019 to June 2019). The time duration of each measurement is one hour and the sampling frequency is set to 20 Hz. Compared with the local meteorological data recorded at the seaside airport of Sydney, the wind speed in the city is at least 50% lower. To calculate the turbulence characteristics of the wind environment, we use a 1-min averaging period to generate the vertical wind profile of turbulent intensity and turbulence length scale. The correlations between the wind speed and wind turbulence characteristics at different measuring sites are examined. The turbulence intensity measured in this study matches with the reference range given in existing guidelines, while the measured turbulence length scale is much smaller than the value given in the guidelines. It is found that the empirical Von-Karman Spectra can be used to describe the frequency distribution of the turbulence at the pedestrian level in urban open space. The insight of this study regarding the vertical wind profile, turbulence intensity and turbulence length scale at the pedestrian height is beneficial for outdoor thermal comfort assessment.
The results of the present CTM simulation show that the convective heat loss of most body segments increases with increasing wind velocity and turbulent intensity and decreasing turbulence length scale. Empirical correlations for predicting convective heat transfer coefficients as a function of the wind velocity, turbulent intensity and turbulence length scale are derived based on simple-geometry assumptions. It is found that, at a given wind velocity and over the ranges of the turbulence conditions from the field measurements, the variations between the high and low values of the convective heat transfer coefficients can be up to 67%. The results of the CTM simulation demonstrate the significance of capturing the turbulent wind conditions for accurately predicting the heat loss from human body for outdoor thermal comfort studies.