Vertical Axis Wind Turbines: Current Technologies and Future Trends

[Abstract] This paper, based on the pursuit of scientific articles published and recorded in the last five years (2010-2014) patents on VAWT technology, gives an image of the current situation of the treated technology. From data extracted we know:The different models that are working with different geometries, distinguishing between Savonius, Darrieus, hybrid of both (D+S), models dedicated to Offshore technology and what can be applied generally (D&S) on both types of VAWT (controllers, electric generators, materials ...). The main countries that research and develop VAWT technology, globally and at European level and the number of dedicated studies and patents each. Multiple applications that can be given in fields such as building, industrial environment, social areas, civil engineering and other more. Future trends for VAWT, which can be seen in our environment, both rural and urban, as has already happened with other renewable technologies for electricity production, as HAWT and photovoltaic (PV), becoming part of the mix of renewable energy technology and business network of the future, thereby contributing to the reduction of CO2 production and economic growt

A new way to obtain climate files in areas with the presence of microclimates by applying the Sandia method: a Galician case study

In order to obtain reliable energy simulation results, it is essential to have accurate climate files corresponding to specific geographical locations. The present work describes a selection process of the Typical Meteorological Months (TMM) that will generate the Typical Meteorological Years (TMY) in eight locations of the Community of Galicia for an analysis period between 2008 and 2017 (10 years). The region of Galicia, located in the northwest of the Iberian Peninsula, due to its particular orography, is prone to the generation of differentiated microclimates in relatively close locations. The process of selecting the typical meteorological months has been carried out following the Sandia Laboratories method. In the present work, data from terrestrial meteorological stations have been combined with solar radiation data obtained from satellite images. Finally, for the validation and comparative study of results, files have been generated in Energy Plus Weather (epw) format. Trends have been checked and typical statistics have been used to analyse the correlations between the files generated with the Sandia method, and the usual reference files (LT, WY, BY). It is observed that with the eight files generated, new differentiated climates are detected, which will affect the improvement of the precision of the energy simulations of buildings that are going to be carried out. For example, in the case of the Campus Lugo and Pedro Murias stations, located in the same climatic zone according to Spanish regulations, differences are observed in the annual averages: DTm (13.7%), WV (41%) or GHI (9%)

Analysis of a nature-inspired shape for a vertical axis wind turbine

[Abstract] Wind energy is gaining special interest worldwide due to the necessity of reducing pollutant emissions and employ renewable resources. Traditionally, horizontal axis wind turbines have been employed but certain situations require vertical axis wind turbines. With a view to improve the efficiency of a vertical axis wind turbine Savonius type, the present work proposes a bioinspired design blade profile relying on the Fibonacci spiral. This shape is repeatedly presented in nature and thus it leads to a bio-inspired blade profile. A numerical model was carried out and it was found that the Fibonacci shape improves the performance of the original Savonius shape, based on semicircular blade profiles. Particularly, the Fibonacci blade profile increases around 14% the power in comparison with the Savonius blade profile. Besides this comparison between Savonius and Fibonacci, a research study was carried out to improve the efficiency of the Fibonacci turbine. To this end, the effect of several parameters was analyzed: number of blades, aspect ratio, overlap, separation gap, and twist angle. Improvements on the average power greater than 30% were obtained

Optimization of a nature-inspired shape for a vertical axis wind turbine through a numerical model and an artificial neural network

[Abstract] The present work proposes an artificial neural network (ANN) to analyze vertical axis wind turbines of the Savonius type. These turbines are appropriate for low wind velocities due to their low starting torque. Nevertheless, their efficiency is too low. In order to improve the efficiency, several modifications are analyzed. First of all, an innovative blade profile biologically inspired is proposed. After that, the influence of several parameters such as the aspect ratio, overlap, and twist angle was analyzed through a CFD (computational fluid dynamics) model. In order to characterize the most appropriate combination of aspect ratio, overlap, and twist angle, an artificial neural network is proposed. A data set containing 125 data points was obtained through CFD. This data set was used to develop the artificial neural network. Once established, the artificial neural network was employed to analyze 793,881 combinations of different aspect ratios, overlaps, and twist angles. It was found that the maximum power coefficient, 0.3263, corresponds to aspect ratio 7.5, overlap/chord length ratio 0.1125, and twist angle 112. This corresponds to a 32.4% increment in comparison to the original case analyzed with aspect ratio 1, overlap 0, and twist angle 0

Años meteorológicos típicos y su influencia en la simulación energética de edificios en regiones con microclimas: el caso de Galicia

Programa Oficial de Doutoramento en Enerxía e Propulsion Mariña. 5014V01[Resumen] En la presente tesis se ha estudiado la influencia del tipo de Año Meteorológico Típico (AMT) sobre los resultados de la simulación energética de edificios y otras instalaciones de aprovechamiento solar térmico. El trabajo realizado está centrado en el sector residencial, y en particular en viviendas unifamiliares. La región de estudio se circunscribe a la Comunidad de Galicia, cuya posición geográfica y orografía confieren la singularidad de la existencia de una variedad de microclimas. Los datos utilizados provienen de los registros históricos de las estaciones meteorológicas terrestres (Xunta de Galicia) gestionadas por MeteoGalicia, y de tres bases de datos de satélites meteorológicos. Han sido elaborados paso a paso ficheros climáticos de referencia basados en Años Meteorológicos Típicos generados según tres de los métodos más reconocidos, así como un cuarto método de referencia comparativa. Se validaron 43 ficheros climáticos por cada método mediante los motores de cálculo Energy Plus™, DOE 2.2™ y TRNSYS™ y se realizaron simulaciones energéticas de una muestra representativa de viviendas unifamiliares tipo y una instalación solar térmica para producción de ACS. Finalmente, se realizaron estudios estadísticos comparativos, así como la representa geográfica de resultados.[Resumo] Nesta tese estudouse a influencia do tipo de Ano Meteorolóxico Típico (AMT) nos resultados da simulación enerxética de edificios e outras instalacións solares térmicas. O traballo desenvolvido céntrase no sector residencial, e en particular nas vivendas unifamiliares. A rexión de estudo limítase á Comunidade de Galicia, cuxa posición xeográfica e orografía confiren a singularidade da existencia dunha variedade de microclimas. Os datos empregados proceden dos rexistros históricos das estacións meteorolóxicas terrestres (Xunta de Galicia) xestionadas por MeteoGalicia, e de tres bases de datos de satélites meteorolóxicos. Elaboráronse paso a paso os ficheiros climáticos de referencia baseados en Anos Meteorolóxicos Típicos xerados segundo tres dos métodos máis recoñecidos, así como un cuarto método comparativo de referencia. Validáronse os 43 ficheiros climáticos para cada método utilizando os motores de cálculo Energy Plus™, DOE 2.2™ e TRNSYS™ e realizáronse simulacións enerxéticas nunha mostra representativa de vivendas unifamiliares típicas e unha instalación solar térmica para a produción de ACS. Finalmente, realizáronse estudos estatísticos comparativos, así como a representación xeográfica dos resultados.[Abstract] In this thesis, the influence of the type of Typical Meteorological Year (AMT) on the results of the energy simulation of buildings and other solar thermal facilities has been studied. The work carried out is focused on the residential sector, and in particular on single‐family homes. The study region is limited to the Community of Galicia, whose geographical position and orography confer the singularity of the existence of a variety of microclimates. The data used comes from the historical records of the terrestrial meteorological stations (Xunta de Galicia) managed by MeteoGalicia, and from three meteorological satellite databases. Reference climate files based on Typical Meteorological Years generated according to three of the most recognized methods, as well as a fourth comparative reference method, have been elaborated step by step. 43 climatic files were validated for each method using the Energy Plus™, DOE 2.2™ and TRNSYS™ calculation engines, and energy simulations were carried out on a representative sample of typical single‐family homes and a solar thermal installation for the production of DHW. Finally, comparative statistical studies were carried out, as well as the geographical representation of results

Diseño de un sistema de propulsion ondulante

Selected Proceedings from the 13th International Congress on Project Engineering. (Badajoz, July 2009)[Abstract] Throughout history the practical implementation of propulsion mechanisms in the fluid environment based on the rotation has been easier to deal because of the state of the art in its time, and this has meant that it has not been more interest a further development of wave based mechanisms which are most of those seen in nature. The Research Group Innovacións Mariñas, attached to the Ship Building Department. (University of A Coruña) is currently developing a wave propeller prototype (based on a invention whose antecedent can be found in invention patent nr. 200002012, author Primitivo B. Gonzalez), applicable to systems and bodies located in fluid environment, and based on the way chosen by first living organisms to move. We are currently finishing the construction of a prototype for trials in a testing tank, whose virtual model has been developed with SOLID EDGE V.18 and its components calculated with the help of finite element module that incorporates this software. Simulation of the propeller performance has been done through software FLUENT 6.3Xunta de Galicia; PGIDIT06DPI172PR