Theoretical Calculation of Wind (Or Water) Turbine: Extending the Betz Limit

Abstract Twisted Darrieus water turbine is receiving growing attentiveness for small-scale hydropower generation. Accordingly, the need for raised water energy conversion incentivizes researchers to focalise on the blade shape optimization of twisted Darrieus turbine. In view of this, an experimental analysis has been performed to appraise the efficiency of a spiral Darrieus water rotor in the present work. To better the performance parameters of the studied water rotor with twisted blades, three novel blade shapes, namely U-shaped blade, V-shaped blade and W-shaped blade, have been numerically tested using a computational fluid dynamics three-dimensional numerical model. Maximum power coefficient of Darrieus rotor reaches 0.17 at 0.63 tip-speed ratio using twisted blades. Using V-shaped blades, maximum power coefficient has been risen up to 0.185. The current study could be practically applied to provide more effective employment of twisted Darrieus turbines and to improve the generated power from flowing water such as river streams, tidal currents, or other man made water canals.

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Performance Prediction and Validation of a Small-Capacity Twisted Savonius Wind Turbine

Energies ◽

10.3390/en12091721 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1721 ◽

Cited By ~ 3

Author(s):

Hyeonmu Jang ◽

Insu Paek ◽

Seungjoo Kim ◽

Deockjin Jeong

Keyword(s):

Fluid Dynamics ◽

Computational Fluid Dynamics ◽

Wind Turbine ◽

Performance Test ◽

Cfd Simulation ◽

Power Production ◽

Maximum Power ◽

Power Coefficient ◽

Speed Ratio ◽

Simulation Results

In this study, an off-grid–type small wind turbine for street lighting was designed and analyzed. Its performance was predicted using a computational fluid dynamics model. The proposed wind turbine has two blades with a radius of 0.29 m and a height of 1.30 m. Ansys Fluent, a commercial computational fluid dynamics solver, was used to predict the performance, and the k-omega SST model was used as the turbulence model. The simulation result revealed a tip-speed ratio of 0.54 with a maximum power coefficient, or an aerodynamic rotor efficiency of 0.17. A wind turbine was installed at a measurement site to validate the simulation, and a performance test was used to measure the power production. To compare the simulation results obtained from the CFD simulation with the measured electrical power performance, the efficiencies of the generator and the controller were measured using a motor-generator testbed. Also, the control strategy of the controller was found from the field test and applied to the simulation results. Comparing the results of the numerical simulation with the experiment, the maximum power-production error at the same wind speed was found to be 4.32%.

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Age- and Activity-Related Differences in the Mechanisms Underlying Maximal Power Production in Young and Older Adults

Journal of Applied Biomechanics ◽

10.1123/jab.2013-0037 ◽

2014 ◽

Vol 30 (1) ◽

pp. 12-20 ◽

Cited By ~ 6

Author(s):

Thomas Korff ◽

Ann H. Newstead ◽

Renate van Zandwijk ◽

Jody L. Jensen

Keyword(s):

Older Adults ◽

Knee Flexion ◽

Power Production ◽

Activity Level ◽

Maximum Power ◽

Maximal Power ◽

Joint Power ◽

Age Related ◽

Peak Knee ◽

Active Adults

The purpose of this study was to examine the interactions between aging, activity levels and maximal power production during cycling. Participants were divided into younger adults (YA), older active adults (OA,) and older sedentary adults (OS). Absolute maximum power was significantly greater in YA compared with OS and OA; no differences were found between OA and OS. The age-related difference in maximum power was accompanied by greater absolute peak knee extension and knee flexion powers. Relative joint power contributions revealed both age- and activity-related differences. YA produced less relative hip extension power than older adults, regardless of activity level. The OS participants produced less relative knee flexion power than active adults, regardless of age. The results show the age-related decline in muscular power production is joint specific and that activity level can be a modifier of intersegmental coordination, which has implications for designing interventions for the aging population.

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ANN and Multiple Linear Regression Based Modelling for Experimental Investigation of Photovoltaic Module Maximum Power Production Under Outdoor Condition of Mountainous Region

Modern Maximum Power Point Tracking Techniques for Photovoltaic Energy Systems - Green Energy and Technology ◽

10.1007/978-3-030-05578-3_8 ◽

2019 ◽

pp. 229-245 ◽

Cited By ~ 4

Author(s):

Amit Kumar Yadav ◽

Hasmat Malik

Keyword(s):

Experimental Investigation ◽

Linear Regression ◽

Multiple Linear Regression ◽

Power Production ◽

Maximum Power ◽

Photovoltaic Module ◽

Mountainous Region ◽

Outdoor Condition

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Experimental Study of Vertical Axis Wind Turbine with Wind Speed Self-Adapting

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.215-216.1323 ◽

2012 ◽

Vol 215-216 ◽

pp. 1323-1326

Author(s):

Ming Wei Xu ◽

Jian Jun Qu ◽

Han Zhang

Keyword(s):

Wind Speed ◽

Wind Turbine ◽

Wind Velocity ◽

Vertical Axis ◽

Maximum Power ◽

The Self ◽

Power Coefficient ◽

Speed Ratio ◽

Vertical Axis Wind Turbine ◽

Opening And Closing

A small vertical axis wind turbine with wind speed self-adapting was designed. The diameter and height of the turbine were both 0.7m. It featured that the blades were composed of movable and fixed blades, and the opening and closing of the movable blades realized the wind speed self-adapting. Aerodynamic performance of this new kind turbine was tested in a simple wind tunnel. Then the self-starting and power coefficient of the turbine were studied. The turbine with load could reliably self-start and operate stably even when the wind velocity was only 3.6 m/s. When the wind velocity was 8 m/s and the load torque was 0.1Nm, the movable blades no longer opened and the wind turbine realized the conversion from drag mode to lift mode. With the increase of wind speed, the maximum power coefficient of the turbine also improves gradually. Under 8 m/s wind speed, the maximum power coefficient of the turbine reaches to 12.26%. The experimental results showed that the new turbine not only improved the self-starting ability of the lift-style turbine, but also had a higher power coefficient in low tip speed ratio.

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Graph Theory-Based Characterization and Classification of Household Photovoltaics

Applied Sciences ◽

10.3390/app112210999 ◽

2021 ◽

Vol 11 (22) ◽

pp. 10999

Author(s):

Jesús M. Ceresuela ◽

Daniel Chemisana ◽

Nacho López

Keyword(s):

Graph Theory ◽

Power Production ◽

Expected Value ◽

Maximum Power ◽

Solar Panels ◽

Zero Energy ◽

Photovoltaic Panel ◽

Clear Goal ◽

Zero Energy Buildings

With the clear goal of improving photovoltaic (PV) technology performance towards nearly-zero energy buildings, a graph theory-based model that characterizes photovoltaic panel structures is developed. An algorithm to obtain all possible configurations of a given number of PV panels is presented and the results are exposed for structures using 3 to 7 panels. Two different classifications of all obtained structures are carried out: the first one regarding the maximum power they can produce and the second according to their capability to produce energy under a given probability that the solar panels will fail. Finally, both classifications are considered simultaneously through the expected value of power production. This creates structures that are, at the same time, reliable and efficient in terms of production. The parallel associations turn out to be optimal, but some other less expected configurations prove to be rated high.

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Real-Time Implementation of the MPPT Control Algorithms of a Wind Energy Conversion System by the Digital Simulator OPAL_RT

European Journal of Electrical Engineering ◽

10.18280/ejee.230106 ◽

2021 ◽

Vol 23 (1) ◽

pp. 45-52

Author(s):

El Oualid Zouggar ◽

Souad Chaouch ◽

Lilia Abdelhamid ◽

Djaffar Ould Abdeslam

Keyword(s):

Real Time ◽

Speed Control ◽

Maximum Energy ◽

Maximum Power ◽

Control Technique ◽

Power Coefficient ◽

Wind Energy Conversion ◽

Point Tracking ◽

Power Point Tracking ◽

Power Point

This paper presents a comparative study between two algorithms for controlling the Wind Turbine (WT) using real time platforms: RT-Lab. The Maximum Power Point Tracking (MPPT) control technique is implemented for extracting the maximum energy from the wind. The first control consists in taking as a reference strategy the electromagnetic torque associated with the maximum power curve. This controller is known as Indirect Speed Control (ISC). The second one, based on the measured wind speed, is called Direct Speed Control (DSC). In this second controller, the effectiveness of the controllers was evaluated with a PI controller and a Fuzzy Logic (FL) controller. The performances are analyzed and compared on the OPAL-RT digital simulator, which is based on the RT-LAB platform with the model, and its control built in Simulink. The results of the simulations clearly show that algorithm based on fuzzy controllers gives better performance in terms of monitoring the maximum power coefficient and optimal speed compared to conventional algorithms.

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