Through-Building Ducts for Mounting Wind Turbines: A Numerical Study

2021 ◽  
Author(s):  
Hadi Mirian ◽  
Morteza Anbarsooz ◽  
Abbas Hoshyar ◽  
Alireza ArabGolarcheh
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Wind Turbines ◽  
Pressure Difference ◽  
Urban Areas ◽  
High Speed ◽  
Numerical Study ◽  
Pressure Coefficient ◽  
Maximum Velocity ◽  
Maximum Pressure

Abstract Yet, several locations for mounting the wind turbines in urban areas have been proposed, which can be categorized into four main groups; (a) on the rooftops, (b) between the buildings, (c) integrated into the buildings’ skin and (d) inside a though-building hole. Through-building holes take advantage of the pressure difference between the windward and leeward facades of the building to generate a high-speed velocity zone for mounting the wind turbine. In the current study, three-dimensional numerical simulations of atmospheric turbulent boundary layer flow around high-rise buildings are carried out to determine the optimum location and size of the duct. For this purpose, square cross-section buildings (20 × 20 m) with heights of H0 = 60, 120 and 180 m are considered. Numerical results showed that the difference of the pressure coefficient on the windward and leeward facades of the building without the hole can predict the best location for mounting the wind turbine with acceptable accuracy. Then, circular holes with various diameters of D = 2.5, 5.0, 7.5, 10 and 12.5m are created at z/H0 = 0.8, where the maximum pressure difference is close to the maximum. It is found that the maximum velocity increment occurs for D = 10 m and it is 31% greater than the U10 velocity of the incident wind profile. This means that the available wind power inside the duct is 2.25 times greater than the incident wind power.

Computational Investigation of a Shrouded Vertical Axis Wind Turbine

2016 ◽  
Author(s):  
K. Vafiadis ◽  
H. Fintikakis ◽  
I. Zaproudis ◽  
A. Tourlidakis
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Urban Areas ◽  
Numerical Study ◽  
Flow Analysis ◽  
Vertical Axis ◽  
Green Energy ◽  
Vertical Axis Wind Turbine ◽  
Wide Range ◽  
Small Wind Turbines

In urban areas, it is preferable to use small wind turbines which may be integrated to a building in order to supply the local grid with green energy. The main drawback of using wind turbines in urban areas is that the air flow is affected by the existence of nearby buildings, which in conjunction with the variation of wind speed, wind direction and turbulence may adversely affect wind energy extraction. Moreover, the efficiency of a wind turbine is limited by the Betz limit. One of the methods developed to increase the efficiency of small wind turbines and to overcome the Betz limit is the introduction of a converging – diverging shroud around the turbine. Several researchers have studied the effect of shrouds on Horizontal Axis Wind Turbines, but relatively little research has been carried out on shroud augmented Vertical Axis Wind Turbines. This paper presents the numerical study of a shrouded Vertical Axis Wind Turbine. A wide range of test cases, were examined in order to predict the flow characteristics around the rotor, through the shroud and through the rotor – shroud arrangement using 3D Computational Fluid Dynamics simulations. The power output of the shrouded rotor has been improved by a factor greater than 2.0. The detailed flow analysis results showed that there is a significant improvement in the performance of the wind turbine.

Wind tunnel and numerical study of multi-storey vertical axis wind turbines with different configurations

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Abhijeet M. Malge ◽  
Prashant Maruti Pawar
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Power ◽  
Wind Turbines ◽  
Numerical Study ◽  
Research Work ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Content Type ◽  
Vertical Axis Wind Turbines

Purpose Three different configurations of vertical axis wind turbines (VAWT) were fabricated by changing the storey height and their orientations. The purpose of this study is to find the effect of storey height and orientation on the performance of wind turbines. The multistory VAWT has three storeys. The first configuration had increased middle storey height, with 0–90-0 orientation of blades. Wherein the second turbine had equal storey heights. The third configuration had increased middle storey height with 0–120-240 orientation of blades. The blades were tested numerically and experimentally. Design/methodology/approach In this research work, prototypes of innovative multistory VAWT were built with different configurations and orientations. Three configurations of three-storey VAWT were fabricated by varying the height of storey of turbines. The orientations were made by keeping the storeys orthogonal to each other. Multistory VAWT was tested numerically and experimentally. ANSYS Fluent was used for computational fluid dynamic analysis of VAWT. K-epsilon model was used for numerical analysis of wind turbine. Experimentation was carried out in a wind tunnel for different tip speed ratios (TSR). Findings The three configurations of innovative multistory VAWT were tested numerically and experimentally for different TSR. It has been found that the VAWT with equal storey height had a better performance as compared to the other two configurations with increased middle storey height. The power coefficient of equal storey height VAWT was about 22%, wherein the power coefficient of turbines with reduced upper and lower storey height was between 5%–8% Research limitations/implications The research work of multi-storey VAWT is very novel and original. The findings of the research will contribute to the existing work done in the field of VAWT. This will help other researchers to have insight into the development of multistory VAWT. The effect of storey height and configuration of multi-storey VAWT is studied numerically and experimentally, which concludes that the performance of equal storey is superior as compared to other configurations. Practical implications The multi-storey concept of VAWT was developed to counter the problem of wind direction. The blades of each storey were arranged orthogonal to each other. This helped to harness wind power irrespective of the direction of the wind. This will make the VAWT more sustainable and financially viable for domestic use. Social implications The turbines are specially designed for remotely located housed in rural areas where the power grid is not yet reached. Users can install the turbine on their rooftop and harness wind power of 100 W capacity. This will help them to make their life easy. Originality/value This research work is very original and first of a kind. The multistory concept of the wind turbine was checked for the effect of storey height and orientations of blades on its performance. Different configurations and orientations of the vertical axis were designed and developed for the first time.

EXPERIMENTAL AND ANALYTICAL STUDIES OF VERTICAL AXIS WIND TURBINES

2018 ◽  
pp. 51-58
Author(s):  
B. P. Khozyainov
Keyword(s):  
Wind Turbine ◽  
Flow Velocity ◽  
Wind Power ◽  
Wind Turbines ◽  
Power Efficiency ◽  
Air Flow ◽  
Geometrical Parameters ◽  
Wind Speeds ◽  
Analytical Studies ◽  
Air Flow Velocity

The article carries out the experimental and analytical studies of three-blade wind power installation and gives the technique for measurements of angular rate of wind turbine rotation depending on the wind speeds, the rotating moment and its power. We have made the comparison of the calculation results according to the formulas offered with the indicators of the wind turbine tests executed in natural conditions. The tests were carried out at wind speeds from 0.709 m/s to 6.427 m/s. The wind power efficiency (WPE) for ideal traditional installation is known to be 0.45. According to the analytical calculations, wind power efficiency of the wind turbine with 3-bladed and 6 wind guide screens at wind speedsfrom 0.709 to 6.427 is equal to 0.317, and in the range of speed from 0.709 to 4.5 m/s – 0.351, but the experimental coefficient is much higher. The analysis of WPE variations shows that the work with the wind guide screens at insignificant average air flow velocity during the set period of time appears to be more effective, than the work without them. If the air flow velocity increases, the wind power efficiency gradually decreases. Such a good fit between experimental data and analytical calculations is confirmed by comparison of F-test design criterion with its tabular values. In the design of wind turbines, it allows determining the wind turbine power, setting the geometrical parameters and mass of all details for their efficient performance.

Performance Study of Wind Turbine Generators

Solar Energy ◽  
2003 ◽  
Author(s):  
G. R. Bhagwatikar ◽  
W. Z. Gandhare
Keyword(s):  
Power Consumption ◽  
Wind Turbine ◽  
Wind Power ◽  
Wind Turbines ◽  
Reactive Power ◽  
Variable Speed ◽  
Turbine Generators ◽  
Wind Turbine Generators ◽  
Utility Grid ◽  
Operational Issues

It is well known that the wind power has definitely certain impact on the grid power. Issues associated with the integration of wind power into the utility grid are interface issues, operational issues and planning issues. Interface issues include harmonics, reactive power consumption, voltage regulation and frequency control. Operational issues are intermittent power generation, operating reserve requirements, unit commitment and economic despatch. And planning issues are concerned with intermittent wind resources compared to conventional power resources. An important question, when connecting the wind turbine generators to the utility grid, is how much the power / voltage quality will be influenced, since the power production by wind turbines is intermittent, quantity wise as well as quality wise. This paper is focused on the on comparison between the constant speed wind turbines and variable speed wind turbines, reactive power consumption and harmonics generated by both wind turbines. Total harmonic distortion is calculated by the application of C++ software and a comparison is done between the generators with respect to the harmonics. It is observed that constant speed wind turbine generates low order harmonics and variable speed turbine generates high order harmonics. On the basis of results, some solutions are suggested to improve the wind power quality and to reduce reactive power consumption. It seems that variable speed wind turbines with electronic interface are better with respect to the utility grid point of view.

scholarly journals Numerical study of various geometries of breakwaters for the installation of floating wind turbines

2016 ◽  
Vol 13 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Keyvan Esmaeelpour ◽  
Rouzbeh Shafaghat ◽  
Rezvan Alamian ◽  
Rasoul Bayani
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Numerical Study ◽  
Energy Resources ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Renewable Energy Resources ◽  
Time Step ◽  
Set Up ◽  
The Right

The everyday growing populations all over the world and the necessity of increase in consumption of fossil energies have made the human to discover new energy resources, which are clean, cheap and renewable. Wind energy is one of the renewable energy resources. Considerable wind speed has made settling of wind turbines at sea beneficial and appealing. For this purpose, choosing the appropriate plates to set up wind turbines on the surface of sea is necessary. Regarding the installation condition, by choosing suitable geometry for floating breakwaters, offshore wind turbine can be mounted on them. Suitable geometry of breakwater for multifunctional usage could be selected with analyzing and comparing pressure, force and moment produced by incoming waves. In this article, we implement boundary element method to solve governing differential equations by assuming potential flow. On the other hand, for promoting free surface in each time step, we employed Euler-Lagrangian method. Finally, to find the appropriate geometry for installing the wind turbine on the breakwater, moment and wave profile next to the right and left side of breakwater body are calculated. Among simulated geometries, breakwater with trapezoid geometry which its larger base is placed in the water has more sustainability and it is the most suitable geometry for wind turbine installation.

scholarly journals An experimental study of the optimal design parameters of a wind power tower used to improve the performance of vertical axis wind turbines

2018 ◽  
Vol 10 (9) ◽  
pp. 168781401879954
Author(s):  
Soo-Yong Cho ◽  
Sang-Kyu Choi ◽  
Jin-Gyun Kim ◽  
Chong-Hyun Cho
Keyword(s):  
Experimental Study ◽  
Optimal Design ◽  
Wind Turbine ◽  
Wind Power ◽  
Wind Turbines ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Design Parameters ◽  
Vertical Axis Wind Turbine ◽  
Vertical Axis Wind Turbines

In order to augment the performance of vertical axis wind turbines, wind power towers have been used because they increase the frontal area. Typically, the wind power tower is installed as a circular column around a vertical axis wind turbine because the vertical axis wind turbine should be operated in an omnidirectional wind. As a result, the performance of the vertical axis wind turbine depends on the design parameters of the wind power tower. An experimental study was conducted in a wind tunnel to investigate the optimal design parameters of the wind power tower. Three different sizes of guide walls were applied to test with various wind power tower design parameters. The tested vertical axis wind turbine consisted of three blades of the NACA0018 profile and its solidity was 0.5. In order to simulate the operation in omnidirectional winds, the wind power tower was fabricated to be rotated. The performance of the vertical axis wind turbine was severely varied depending on the azimuthal location of the wind power tower. Comparison of the performance of the vertical axis wind turbine was performed based on the power coefficient obtained by averaging for the one periodic azimuth angle. The optimal design parameters were estimated using the results obtained under equal experimental conditions. When the non-dimensional inner gap was 0.3, the performance of the vertical axis wind turbine was better than any other gaps.

Nondimensional Parameters’ Effects on Hybrid Darrieus–Savonius Wind Turbine Performance

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Armin Roshan ◽  
Amir Sagharichi ◽  
Mohammad Javad Maghrebi
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Power Output ◽  
Urban Areas ◽  
Model Performance ◽  
Vertical Axis ◽  
Favorable Effect ◽  
Turbine Performance ◽  
Primary Model ◽  
Overlap Ratio

Abstract Vertical axial wind turbines are the most commonly used turbines in residential and urban areas. This paper investigates the effect of combining Darrieus and Savonius wind turbines on power output and introduces a wind turbine with high starting torque addition to the wide working domain. A two-dimensional computational fluid dynamics transient simulation is developed, and a moving mesh is implemented for rotating moving parts. Comprehensive research has been carried out to investigate the effects of the initial overlap ratio (ɛ), arc angle Ø, and curvature (α) of Savonius blades on the performance of the turbine and 18 models are simulated at seven tip speed ratios. The results showed that combining the Darrieus turbine with the Savonius turbine has a favorable effect on self-starting performance. Also, it was observed that by changing each of the parameters, the primary model performance could be significantly improved. Finally, it is concluded that ɛ = 0.25, α = 0.25, and ∅ = 150 deg are the optimum values of the parameters which increase turbine power output compared to conventional vertical-axis turbines.

Improvement in Savonius Wind Turbines Efficiency by Modification of Blade Designs—A Numerical Study

2019 ◽  
Vol 142 (6) ◽  
Author(s):  
Praveen Laws ◽  
Jaskaran Singh Saini ◽  
Ajit Kumar ◽  
Santanu Mitra
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Power Efficiency ◽  
Numerical Study ◽  
Speed Ratio ◽  
Published Data ◽  
Blade Design ◽  
Simple Modification ◽  
Mesh Structure ◽  
Flow Equations

Abstract Savonius wind turbines are special class of vertical axis wind turbines (VAWTs). These are low-cost drag-driven turbines and are known to be inefficient. It is proposed in this study that a simple modification to the turbine blade design can yield a significant improvement in power efficiency. The performance of the new design is extensively studied on openfoam-v1812, a popular open source computational fluid dynamics (CFD) library. The flow equations coupled with equations of rotation of the turbine are solved on an overset mesh framework. This study also serves as a validation of recently released overset support in openfoam. The turbulence is incorporated by coupling Reynolds-averaged Navier–Stokes (RANS) with shear stress transport (SST) κ − ω eddy viscosity turbulence model. The turbulence parameters are set to produce a flow with the Reynolds number, Re = 4.8 × 105. To have better confidence in simulations, this study also presents a comparison of numerical flow over conventional Savonius turbine designs with the published data. It is observed that a majority of CFD analysis on wind turbine designs are performed for the fixed tip speed ratio on a traditional static mesh structure. But, in this CFD study, a wind-driven rotation of Savonius turbine is simulated on an overset dynamics approach. The results of the study are compared and discussed based on the predicted moment and power coefficients, pressure variation on the blades, flow velocity field, and wake analysis. The study indicates that the blade design presented here has a potential to increase the power efficiency of a Savonius wind turbine by 10–28%.

Dynamic Simulation of a Wind Farm With Variable Speed Wind Turbines

2003 ◽  
Author(s):  
E. Muljadi ◽  
C. P. Butterfield
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Wind Turbines ◽  
Wind Farm ◽  
Reactive Power ◽  
Power Network ◽  
Variable Speed ◽  
Power Capacity ◽  
Advantages And Disadvantages ◽  
The Impact

Wind power generation has increased very rapidly in the past few years. The total U.S. wind power capacity by the end of 2001 was 4,260 megawatts. As wind power capacity increases, it becomes increasingly important to study the impact of wind farm output on the surrounding power networks. In this paper, we attempt to simulate a wind farm by including the properties of the wind turbine, the wind speed time series, the characteristics of surrounding power network, and reactive power compensation. Mechanical stress and fatigue load of the wind turbine components are beyond the scope this paper. The paper emphasizes the impact of the wind farms on the electrical side of the power network. A typical wind farm with variable speed wind turbines connected to an existing power grid is investigated. Different control strategies for feeding wind energy into the power network are investigated, and the advantages and disadvantages are presented.

Feasibility analysis of a new tree-shaped wind turbine for urban application: A case study

2019 ◽  
Vol 31 (7) ◽  
pp. 1230-1256
Author(s):  
Ali Mostafaeipour ◽  
Mostafa Rezaei ◽  
Mehdi Jahangiri ◽  
Mojtaba Qolipour
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Urban Areas ◽  
High Efficiency ◽  
Cost Effective ◽  
Electricity Production ◽  
Levelized Cost Of Electricity ◽  
Wind Turbine System ◽  
Wind Power System ◽  
Bandar Abbas

In this study, feasibility of a new wind power generation system for urban application in Hormozgan Province of Iran is investigated. The wind turbine system in this study is a novel, aesthetically pleasing, noiseless, pollution-free, potentially cost-effective, and high efficiency design called tree-shaped wind turbine (TSWT). Techno-economic evaluation is performed on eight urban areas in the province using the software HOMER. Multi-criteria decision making approaches are used to prioritize the areas in terms of the best location for installing such a new system. The results of techno-economic analysis examining a wind power system consisting of 25 TSWTs show that the most electricity production would occur for Jask city which is 529,450 kWh/yr. Also, the least amount of electricity which is 339,275 kWh/yr belongs to Bandar Abbas. Considering the most important criteria including electricity production, levelized cost of electricity, population, land price, environmental impact, and frequency of natural disasters, data envelopment analysis, and the fuzzy technique for order of preference by similarity to ideal solution are employed to rank the cities. The results are validated by two different methods. Finally, it is suggested that Sirik is the best location for using the aforementioned wind turbine.

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