scholarly journals Design and fabrication of a low-cost Darrieus vertical-axis wind-turbine system. Phase I. Executive summary

1979 ◽  
Author(s):  
Brett C. Krippene ◽  
Ira Sorensen

A conceptual design is presented of a roof-top type, MULTI-PHASED VERTICAL AXIS WIND TURBINE SYSTEM with an ADJUSTABLE INLET AIR SCOOP and EXIT DRAG CURTAIN at a 100 Watt to 50 kWe commercial scale. The MULTI-PHASED VERTICAL AXIS WIND TURBINE (MVAWT) SYSTEM is cost effective in an environmentally friendly manner. It is especially useful in areas where it can benefit from the wind velocity increasing and streamlining effects that may occur around small hills, roof tops and tall buildings. The MVAWT system concentrates, collects and utilizes the available energy in the wind by way of a naturally yawed, downwind seeking, vertical axis orientated flow tube and integrated air turbine assembly with adjustable inlet air scoop and outlet drag sections mounted on the flow tube. The MVAWT system’s air turbine is a combination radial or mixed out-flow and reaction cross-flow type centrifugal fan design as mounted on the discharge end of the flow tube. This air turbine, being more of a radial instead of an axial flow or propeller type design, can potentially exceed the Betz limit of 59.26% energy recovery or effectiveness from the maximum energy available from the wind flowing through the inlet flow tube. A low pressure drop screen can be provided at the inlet and outlet to protect flying birds and mammals from being drawn into the integrated flow tube and air turbine assembly. Additionally, access to the rotating components for inspection and maintenance purposes is much safer, easier and less costly than with conventional propeller type wind turbine systems mounted on tall towers. No multiple staged wind turbine system as described herein has as yet been researched as to its technical feasibility and developed to the point of a prototype demonstration at a commercial size. Such parameters as overall performance, energy conversion efficiency, costs (installed, operating and maintenance), system reliability, public acceptance and environmental impacts have not yet been truly assessed. A Phase I - technical feasibility assessment and Phase II - prototype demonstration program for a nominal 10 kWe sized Multi-Phased Vertical Axis Wind Turbine system with an average power output in a 16 mph wind of as much as 2 kWe (kW-hr / hr) and as much as 10 kWe (kW-hr / hr) at a 28 mph wind velocity is suggested to provide this essential information to both the authors and the public at large.


Author(s):  
Hagninou E. V. Donnou ◽  
Drissa Boro ◽  
Donald Abode ◽  
Brunel Capo-Chichi ◽  
Aristide B. Akpo

The design of a vertical axis wind turbine (Darrieus type) adapted to the site of Cotonou in the coastal region of Benin was investigated. The statistical study of winds based on the Weibull distribution was carried out on hourly wind data measured at 10 m above the ground by the Agency for the Safety of Air Navigation in Africa and Madagascar (ASECNA) over the period from January 1981 to December 2014. The geometrical and functional parameters of the wind turbine were determined from different models and aerodynamic approaches. The digital design and assembly of the wind turbine components were carried out using the TOPSOLID software. The designed wind turbine has a power of 200W. It is equipped with a synchronous generator with permanent magnets and has three wooden blades with NACA 0015 profile. The optimal coefficient of lift and drag were estimated respectively at 0.7832 and 0.01578. The blades are characterized by an optimum angle of attack estimated at 6.25° with a maximum fineness of 49.63. Their length is 4 m and the maximum thickness is estimated at 0.03 m with a chord of 0.20 m. The volume and mass are respectively equal to 0.024 m3 and 36 kg. The aerodynamic stall occurs at an attack angle of 14.25°. The aerodynamic force exerted on these blades is estimated to be 240 N. The aerodynamic stresses exerted on the rotor are estimated at 15 864 504 Pa and the solidity at 0.27. The efficiency of the wind turbine is 0.323. From TOPSOLID, the geometrical shape of each component of the wind turbine is represented in three dimensions. The assembly allowed to visualizing the wind turbine after export via its graphical interface. The quantity of annual energy produced by the wind turbine was estimated at 0.85 MWh. This study is the first to be carried out in the study area and could reduce the technological dependence of vertical axis wind turbines and their import for low cost energy production.


Vertical axis wind turbines are most effective for home energy generation especially in urban environments. Wind energy creates a stand-alone energy source that is relied on any place. The main criteria for this work is the design of micro wind turbines for all kinds of applications. Design of Twisted Blade Micro-Wind Turbine system is accomplished using computer aided design with Computational Fluid Dynamics (CFD). The flow characteristics in the wind turbine blade were analyzed by varying its twist ratio. The wind turbines with vertical axis utilize the wind from any direction with no yaw mechanism. The risk of blade ejection besides catching wind from all the directions is avoided by using the helical tye vertical axis wind turbine.


Author(s):  
Jinwook Kim ◽  
Dohyung Lee ◽  
Junhee Han ◽  
Sangwoo Kim

The Vertical Axis Wind Turbine (VAWT) has advantages over Horizontal Axis Wind Turbine (HAWT) that it allows less chance to be degraded independent of wind direction and turbine can be operated even at the low wind speed. The objective of this study is to analyze aerodynamics of the VAWT airfoil and investigate the ideal shape of airfoil, more specifically cambers. The analysis of aerodynamic characteristics with various cambers has been performed using numerical simulation with CFD software. As the numerical simulation discloses local physical features around wind turbine, aerodynamic performance such as lift, drag and torque are computed for single airfoil rotation and multiple airfoil rotation cases. Through this study more effective airfoil shape is suggested based vortex-airfoil interaction studies.


Author(s):  
David MacPhee ◽  
Asfaw Beyene

Blade pitch control has been extremely important for the development of Horizontal-Axis Wind Turbines (HAWTs), allowing for greater efficiency over a wider range of operational regimes when compared to rigid-bladed designs. For Vertical-Axis Wind Turbines (VAWTs), blade pitching is inherently more difficult due to a dependence of attack angle on turbine armature location, shaft speed, and wind speed. As a result, there have been very few practical pitch control schemes put forward for VAWTs, which may be a major reason why this wind turbine type enjoys a much lower market share as compared to HAWTs. To alleviate this issue, the flexible, straight-bladed vertical-axis turbine is presented, which can passively adapt its geometry to local aerodynamic loadings and serves as a low-cost blade pitch control strategy increasing efficiency and startup capabilities. Using two-dimensional fluid-structure action simulations, this novel concept is compared to an identical rigid one and is proven to be superior in terms of power coefficient due to decreased torque minima. Moreover, due to the flexible nature of the blades, the morphing turbine achieves less severe oscillatory loadings. As a result, the morphing blade design is expected to not only increase efficiency but also system longevity without additional system costs usually associated with active pitch control schemes.


2013 ◽  
Vol 446-447 ◽  
pp. 709-715 ◽  
Author(s):  
M. Shahrukh Adnan Khan ◽  
Rajprasad K. Rajkumar ◽  
Rajparthiban K. Rajkumar ◽  
C.V. Aravind

In this paper, the performances of all the three kinds of Axial type Multi-Pole Permanent Magnet Synchronous Generators (PMSG) namely Three-phase, Multi-phase or Five Phase and Double Stator fixed in Vertical Axis Wind Turbine (VAWT) were investigated and compared in order to get an optimal system. MATLAB/Simulink had been used to model and simulate the wind turbine system together with all the three types Permanent Magnet Generators. It was observed from the result that with the increasing number of pole in both low and high wind speed, the five phase generator produced more power than the other two generators. In general, it was observed that the responses of the Multi-phase generator at both high and low speed wind showed promising aspect towards the system followed by Dual Stator. But with the change of the variables such as wind velocity, turbine height, radius, area together with the generator pole pairs and stator resistance, the optimum system should be chosen by considering the trade-off between different configurations which were firmly analyzed and described in this paper.


2015 ◽  
Vol 813-814 ◽  
pp. 1070-1074
Author(s):  
T. Micha Premkumar ◽  
T. Mohan ◽  
Sivamani Seralathan ◽  
A. Sudheer Kumar

The capacity of wind power generation has increased across India due to various activities encouraged by government. Moreover, onshore potential in India is in the order of 100GW. However, the plant load factor is often very low in wind power production. In most of the place, low-rated wind speed is available. Effective utilization of the wind to produce small power will reduces the grid load. There is in need to effectively utilize the available potential to meet the energy demand. The low cost vertical axis wind turbine designed for low rated wind regime has the hybrid of simple Savonius and helical Savonius. Various experimental parameters are measured to check the suitability of the vertical axis wind turbine in the low rated wind speed regions. Numerical simulation are carried out for three dimensional steady flow around the combined Savonius and helical Savonius vertical axis wind turbine blades using ANSYS Fluent(C). Numerical investigation are conducted to study the effect of hybrid combination on performance of the rotor in terms of coefficient of torque, coefficient of power, etc. Self-starting behaviour of the vertical axis wind turbine is improved by using this hybrid vertical axis wind turbine.


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