Small Wind Turbines in the Built Environment: Influence of Flow Inclination on the Potential Energy Yield

2013 ◽  
Vol 136 (4) ◽  
Author(s):  
Serena Bianchi ◽  
Alessandro Bianchini ◽  
Giovanni Ferrara ◽  
Lorenzo Ferrari
Keyword(s):  
Built Environment ◽  
Potential Energy ◽  
Wind Turbines ◽  
Local Governments ◽  
Energy Yield ◽  
Simulation Code ◽  
Specific Flow ◽  
Small Wind Turbines ◽  
Horizontal Axis Wind Turbines ◽  
The Impact

Increasing interest is being paid by architects, project developers and local governments to understanding where small wind turbines can effectively be exploited to provide delocalized power in the built environment. The wind conditions in the rooftop area of buildings in urban locations are, however, very complex and the real adaptability of wind turbines to these environments is not yet tested both in terms of real producibility and of structural compatibility with the building themselves. In these installations, in particular, the flow that incomes on the rotor is often inclined with respect to the horizontal direction due to the interaction with the building façade and the roof. A correct estimation of the impact of an inclined flow on the performance of horizontal-axis wind turbines, therefore, becomes a very relevant issue to correctly predict the potential energy yield of a machine. To this purpose, a simulation code based on a blade element momentum (BEM) approach was developed and validated by means of experimental data found in the literature. The code was then used to evaluate the energetic suitability of a small-size wind turbine installation in the rooftop of a building in a conventional European city. A numerical computational fluid dynamics (CFD) analysis was carried out to characterize the flow field in the rooftop area of different buildings. The flow velocity modulus and direction were calculated for several oncoming wind profiles: The results were projected into an available wind power curve in the rooftop of the building. The effective energy-yield capabilities were then corrected using the model for the flow inclination as a function of the specific flow conditions in the rooftop area. The results were finally exploited to analyze the energy-oriented feasibility of an installation in a similar context.

Small Wind Turbines in the Built Environment: Influence of Flow Inclination on the Potential Energy Yield

2013 ◽  
Author(s):  
Serena Bianchi ◽  
Alessandro Bianchini ◽  
Giovanni Ferrara ◽  
Lorenzo Ferrari
Keyword(s):  
Built Environment ◽  
Potential Energy ◽  
Wind Turbines ◽  
Local Governments ◽  
Energy Yield ◽  
Simulation Code ◽  
Specific Flow ◽  
Small Wind Turbines ◽  
Horizontal Axis Wind Turbines ◽  
The Impact

Increasing interest is being paid by architects, project developers and local governments to understand where small wind turbines can effectively be exploited to provide delocalized power in the built environment. The wind conditions in the rooftop area of buildings in urban locations are, however, very complex and the real adaptability of wind turbines to these environments is not yet tested both in terms of real producibility and of structural compatibility with the building themselves. In these installations, in particular, the flow which incomes on the rotors is often inclined with respect to the horizontal direction due to the interaction with the building façade and the roof. A correct estimation of the impact of an inclined flow on the performance of horizontal-axis wind turbines therefore becomes a very relevant issue to correctly predict the potential energy yield of a machine. To this purpose, a simulation code based on a Blade Element Momentum (BEM) approach was developed and validated by means of experimental data found in the literature. The code was then used to evaluate the energetic suitability of a small-size wind turbine installation in the rooftop of a building in a conventional European city. A numerical CFD analysis was carried out to characterize the flow field in the rooftop area of different buildings. The flow velocity modulus and direction were calculated for several oncoming wind profiles: the results were projected into an available wind power curve in the rooftop of the building. The effective energy-yield capabilities were then corrected using the model for the flow inclination as a function of the specific flow conditions in the rooftop area. The results were finally exploited to analyze the energy-oriented feasibility of an installation in a similar context.

Numerical Implications of Solidity and Blade Number on Rotor Performance of Horizontal-Axis Wind Turbines

2003 ◽  
Vol 125 (4) ◽  
pp. 425-432 ◽  
Author(s):  
Matthew M. Duquette ◽  
Kenneth D. Visser
Keyword(s):  
Wind Turbines ◽  
High Speed ◽  
Numerical Study ◽  
Power Extraction ◽  
Blade Number ◽  
Small Wind Turbines ◽  
Horizontal Axis Wind Turbines ◽  
The Impact ◽  
Lifting Line ◽  
System Power

A numerical study was conducted to examine the impact of rotor solidity and blade number on the aerodynamic performance of small wind turbines. Blade element momentum theory and lifting line based wake theory were utilized to parametrically assess the effects of blade number and solidity on rotor performance. Increasing the solidity beyond what is traditionally used for electric generating wind turbines led to increased power coefficients at lower tip speed ratios, with an optimum between 3 and 4. An increase in the blade number at a given solidity also increased the maximum Cp for all cases examined. The possibility of a higher aerodynamic power extraction from solidity or blade number increases could lead to a higher overall system power production. Additional advantages over current 5% to 7% solidity, high speed designs would include lower noise, lower cut-in wind speed, and less blade erosion.

Urban wind conditions and small wind turbines in the built environment: A review

2019 ◽  
Vol 131 ◽  
pp. 268-283 ◽  
Author(s):  
Anup KC ◽  
Jonathan Whale ◽  
Tania Urmee
Keyword(s):  
Built Environment ◽  
Wind Turbines ◽  
Small Wind Turbines

Development and Application of a Simulation Tool for Vertical and Horizontal Axis Wind Turbines

2013 ◽  
Author(s):  
David Marten ◽  
Juliane Wendler ◽  
Georgios Pechlivanoglou ◽  
Christian Navid Nayeri ◽  
Christian Oliver Paschereit
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Vertical Axis ◽  
Turbine Rotor ◽  
Horizontal Axis ◽  
Vertical Axis Wind Turbine ◽  
First Case ◽  
Horizontal Axis Wind Turbines ◽  
Lift And Drag ◽  
The Impact

A double-multiple-streamtube vertical axis wind turbine simulation and design module has been integrated within the open-source wind turbine simulator QBlade. QBlade also contains the XFOIL airfoil analysis functionalities, which makes the software a single tool that comprises all functionality needed for the design and simulation of vertical or horizontal axis wind turbines. The functionality includes two dimensional airfoil design and analysis, lift and drag polar extrapolation, rotor blade design and wind turbine performance simulation. The QBlade software also inherits a generator module, pitch and rotational speed controllers, geometry export functionality and the simulation of rotor characteristics maps. Besides that, QBlade serves as a tool to compare different blade designs and their performance and to thoroughly investigate the distribution of all relevant variables along the rotor in an included post processor. The benefits of this code will be illustrated with two different case studies. The first case deals with the effect of stall delaying vortex generators on a vertical axis wind turbine rotor. The second case outlines the impact of helical blades and blade number on the time varying loads of a vertical axis wind turbine.

Circulation Control Applied to Wind Turbines

2009 ◽  
Author(s):  
David McGrain ◽  
Gerald M. Angle ◽  
Jay P. Wilhelm ◽  
Emily D. Pertl ◽  
James E. Smith
Keyword(s):  
Wind Energy ◽  
Wind Turbines ◽  
Power Output ◽  
Alternative Energy ◽  
Vertical Axis ◽  
Limiting Factor ◽  
Circulation Control ◽  
Bird Populations ◽  
Horizontal Axis Wind Turbines ◽  
The Impact

The recent rise in fuel costs and global warming concerns have re-invigorated the search for alternative energy sources. Harnessing energy from the wind is a logical alternative; however the cost and efficiency of current wind turbines is a limiting factor. The use of an augmented Vertical Axis Wind Turbines (VAWTs) may become the superior choice to the more common Horizontal Axis Wind Turbines (HAWTs) that are usually associated with the harvesting of wind energy. HAWTs operate on the same principles as large airplane propellers, while VAWTs operate on lift and/or drag principles like an airplane wing or a sail on a boat. VAWTs are currently being investigated for use with circulation control to increase their potential power output. In this paper, two topics will be presented, a comparison between VAWTs and HAWTs for rotor diameter versus key turbine aspects and the impact of VAWTs on environmental concerns, such as bat and bird populations. The Center for Industrial Research Applications (CIRA) at West Virginia University (WVU) is currently developing a concept utilizing circulation control to increase the lift to drag ratio, maximizing the beneficial forces on the VAWT blade, allowing for improved wind energy production. For the comparison between VAWTs and HAWTs, there are currently 14 companies with a total of 34 wind turbines variations representing VAWTs and 11 companies with a total of 40 wind turbines representing HAWTs. Trend studies of VAWT and HAWT diameters to cut-in-speed, rated velocity, max velocity, power output (<100 kW), and power output (≥100 kW) were created to show the potential of VAWTs. A growing concern with wind energy is the impact on bat and bird populations. It is currently believed that VAWTs reduce the impact of wind energy by altering the interaction with the wind. If these benefits can be proven, then not only are VAWTs potentially more economical, but even more eco-friendly.

scholarly journals Wind Resource Assessment and Economic Viability of Conventional and Unconventional Small Wind Turbines: A Case Study of Maryland

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5874
Author(s):  
Navid Goudarzi ◽  
Kasra Mohammadi ◽  
Alexandra St. St. Pé ◽  
Ruben Delgado ◽  
Weidong Zhu
Keyword(s):  
Power Generation ◽  
Wind Speed ◽  
Wind Turbines ◽  
Payback Period ◽  
Small Scale ◽  
Small Wind Turbines ◽  
Mean Wind Speed ◽  
Wind Resource ◽  
The Impact

Annual mean wind speed distribution models for power generation based on regional wind resource maps are limited by spatial and temporal resolutions. These models, in general, do not consider the impact of local terrain and atmospheric circulations. In this study, long-term five-year wind data at three sites on the North, East, and West of the Baltimore metropolitan area, Maryland, USA are statistically analyzed. The Weibull probability density function was defined based on the observatory data. Despite seasonal and spatial variability in the wind resource, the annual mean wind speed for all sites is around 3 m/s, suggesting the region is not suitable for large-scale power generation. However, it does display a wind power capacity that might allow for non-grid connected small-scale wind turbine applications. Technical and economic performance evaluations of more than 150 conventional small-scale wind turbines showed that an annual capacity factor and electricity production of 11% and 1990 kWh, respectively, are achievable. It results in a payback period of 13 years. Government incentives can improve the economic feasibility and attractiveness of investments in small wind turbines. To reduce the payback period lower than 10 years, modern/unconventional wind harvesting technologies are found to be an appealing option in this region. Key contributions of this work are (1) highlighting the need for studying the urban physics rather than just the regional wind resource maps for wind development projects in the build-environment, (2) illustrating the implementation of this approach in a real case study of Maryland, and (3) utilizing techno-economic data to determine suitable wind harnessing solutions for the studied sites.

scholarly journals The suitability of the IEC 61400-2 wind model for small wind turbines operating in the built environment

2017 ◽  
Vol 2 ◽  
pp. 31 ◽  
Author(s):  
Samuel P. Evans ◽  
Anup KC ◽  
David R. Bradney ◽  
Tania P. Urmee ◽  
Jonathan Whale ◽  
...  
Keyword(s):  
Built Environment ◽  
Wind Turbines ◽  
Wind Model ◽  
Small Wind Turbines

Yaw Control of Small Wind Turbines With a New Passive Tail Device: Part 1 — Steady-State Case

Solar Energy ◽  
2003 ◽  
Author(s):  
Eduardo Rinco´n Meji´a ◽  
Jesu´s Tovar Salazar ◽  
Jo´zef Wo´jcik Filipek
Keyword(s):  
Steady State ◽  
Wind Turbine ◽  
Field Test ◽  
Wind Turbines ◽  
Strong Wind ◽  
Test Results ◽  
Yaw Control ◽  
Small Wind Turbines ◽  
Horizontal Axis Wind Turbines ◽  
State Case

This paper describes the behavior of a new tail device to yaw smoothly small wind turbine rotors out of the wind during strong wind or gusts. The passive tail device consists of a rigid short tail, an aerodynamic rotating vane, a tail bumper, and a spring. This passive tail device reduces gyroscopic loads, is easy to adjust, can be manufactured in smaller sizes, and is much stronger than conventional vanes used in small wind machines. Besides, the energy collected with it is greater. Field test results indicate that its behavior agrees very well with simulations, and that the regulator can be advantageously utilized, as compared with conventional vanes and other mechanical or electromechanical means, in horizontal-axis wind turbines with diameters of 12 m or smaller. Here the steady-state case (quasi-steady wind velocity is assumed) is analyzed, showing the technical viability of the regulator proposed.

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