Contexto: Las turbinas eólicas de eje vertical, y en particular las turbinas de arrastre tipo Savonius, aventajan a los otros tipos de turbinas en aplicaciones que comprenden vientos erráticos y de baja velocidad. Si bien su eficiencia está entre las más bajas, esto puede verse compensado con sus bajos costos, lo que las convierte en una alternativa sostenible y atractiva para este tipo de aplicaciones. En esta investigación se busca seleccionar la geometría de mayor rendimiento para el álabe de una turbina eólica tipo Savonius.
Método: Para ello, se analizan numéricamente diversas configuraciones geométricas empleadas en este tipo de turbinas, las cuales fueron consultadas en la literatura. Todos los modelos de perfil son estudiados bajo los mismos parámetros y modelos de dinámica de fluidos computacional a través del software ANSYS Fluent.
Resultados: A través de las simulaciones computacionales se estiman las condiciones de optimo rendimiento de cada una de las geometrías. Dichas condiciones permiten comparar, bajo los mismos términos, el desempeño de los perfiles e identificar los de mayor rendimiento. Se determina que el perfil semicircular convencional y el conocido como Bach modificado presentan coeficientes de potencia de 0,287 y 0,395 respectivamente, lo que representa un aumento en su rendimiento del 37,8 %.
Conclusiones: Este resultado superior motiva a un análisis detallado del perfil Bach modificado que permita encontrar las proporciones geométricas óptimas para su desempeño aerodinámico.

Estudio de desempeño de distintos perﬁles de álabe de una turbina eólica para aprovechar vientos de baja velocidad

A hybrid tree is an artificial structure resembling a natural tree with branches on top of which are mounted solar modules or wind turbines. It can help supply power to mobile phones, laptops, electric vehicles, home appliances and lighting loads covering small or large areas, which can be the best energy source for sustainable cities and modern societies. This paper presents a 3 kW hybrid tree design consisting of 2 kW solar and 1 kW wind to be installed at Vaddeswaram, Andhra Pradesh (16.26°N and 80.36°E) which can generate maximum energy using a two-axis tracking system. Different designs and applications of energy trees available worldwide are also presented. P–V and I–V characteristics of solar panels were obtained at different irradiance and temperature values. For wind turbine, power characteristics at different wind speed and co-efficient of power at different tip speed ratios were studied. Power generation study for the hybrid tree was carried out at different tilt angles from 10° to 20° for solar panels. Structural optimisations are performed to validate whether the structure can withstand the loads applied. The proposed solar-wind hybrid tree can generate 4709 kWh/year with the two-axis tracking system instead of generating 3763 kWh/year when solar panels are fixed at an 18.25° tilt angle. 

Design and analysis of a solar-wind hybrid renewable energy tree

Wind energy is an alternative source of clean energy to address the growing energy demand and provide pollution-free electricity. With the rapid development of urban areas, high wind energy resources such as high-rise building rooftops are excellent locations for urban wind turbine installation. One of the practical and simple urban wind turbines is the Savonius design. It has a simple design, easy to maintain, and is very affordable. This work focuses on the design evaluation of a Savonius wind turbine (SWT) by varying the rotor diameter, rotor height, and twist angle for urban applications. A transient computational fluid dynamics (CFD) approach is applied to assess the various design treatments using a space-filling design of experiments. To address the spaces in the hypercube statistical design, a sphere packing design method was adopted which suited the evaluation of computational simulations results such as that of the CFD. The Gaussian stochastic process model was applied to establish the trend of the parametric performance of the optimized SWT design through the model fitting. The results have shown that optimized SWT performs well with its self-starting capability compared to the traditional Savonius design. In addition, the optimized SWT has shown a better peak power coefficient compared with the results of previous works on the design of SWT.

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Savonius Wind Turbine Numerical Parametric Analysis Using Space-Filling Design and Gaussian Stochastic Process

This study investigates the helical blades of a wind turbine as described in a recent patent for an independent lighting base. At four-time steps, the present work evaluated the displacement parameters, physical stress, and strain on the helical blades of a Savonius wind turbine, such as von mises stress, equivalent strain, first and third principal stress, and strain. Stresses are examined on the material, and this value is compared with the yield stress of the material in the finite element software of Autodesk Inventor Professional. According to the results, maximum and minimum values of von mises stress are 9.5987 MPa at the bottom of the helical blade and 9.9962E-5 MPa in the middle of the helical blade, respectively. Also, maximum and minimum values of equivalent strain are 12.3549E-5 at the bottom of the helical blade and 13.2388E-10 in the middle of the blade, respectively. Finally, maximum and minimum values of total displacement are 1.6792E-2 at time step 2 on top of the blade. Also, the minimum value of displacement is 1.2839E-5 at time step 1 at the bottom of the blade. • Hybrid Investigation of the Helical Blades of Savonius Wind Turbine as described in a recent patent for an independent lighting base. • Full evaluation the displacement parameters, physical stress, and strain on the helical blades. • Using Finite element software of Autodesk Inventor Professional for analyzing Influence of Physical characteristics of the helical savonius blade. 

Hybrid Investigation of the Helical Blades of Savonius Wind Turbine in novel patent of lighting base

—The rotor is a critical component in converting kinetic energy into electrical energy in the turbine. There are many types of turbines, one of which is the Savonius Turbine, a kind of cross-flow turbine. In recent years, research on improving the performance of the Savonius turbine has continued to develop. Several factors that affect the performance of the Savonius turbine are external factors, geometry, and materials. One of the Savonius turbine performances is influenced by the rotor geometry. Several studies have shown that modification of the geometry of the Savonius rotor can improve turbine performance. Some of the changes made are variations in aspect ratio, overlap ratio, the shape of a blade, number of blades, and multi-stage. This research is a mini-review of the geometry modifications that influence the performance of the Savonius turbine. This study aims to show the geometric factors that influence the performance of Savonius and compare the magnitude of these factors' Influence in increasing the Savonius turbine's performance. Reviews show that the Aspect Ratio is directly proportional to performance. Overlap variation of 0 to 0.3 has resulted in the best performance on the Savonius turbine, but other factors also influence this factor. The modified shape of the blade provides an increase of 8% - 25%. Multi-Stage on the Savonius can be a combination factor with other factors to maximize the performance of the Savonius rotor. The number of blades that have resulted in the best performance and stability against other factors is two-blades and three-blades.

Effect of Geometry Modification on Turbine Performance: Mini-Review of Savonius Rotor

This study is conducted to investigate the performance of a modified Savonius wind turbine. A 2-dimensional rotor blade model is introduced for computational analysis using ANSYS-Fluent. To make the analysis, Shear-Stress Transport (SST) k-ω turbulence model is used to conduct the analysis. The proposed modified model is compared with a reference model. The coefficient of power (CP), coefficient of torque (CT), and total power (P) for several tip speed ratio (TSR) is evaluated considering single rotation. The proposed model depicted its best performance for all parameters at TSR ​= ​1.1 than the reference conventional model (TSR ​= ​0.7). Furthermore, the proposed model also surpasses the performance of the conventional one at TSR ​= ​0.7. The optimal torque was found 7.02 ​N-m, which is 62.5% higher than the traditional design.

M.M. Roshid

Papers

A computational study on the aerodynamic performance of modified savonius wind turbine