Research on the Performance of Point Absorber

2014 ◽  
Vol 1008-1009 ◽  
pp. 1180-1185
Author(s):  
Xiong Bo Zheng ◽  
Yu Nong Yang ◽  
Peng Xie
Keyword(s):  
Energy Conversion ◽  
Conversion Efficiency ◽  
Wave Energy ◽  
Energy Conversion Efficiency ◽  
Energy Crisis ◽  
Great Contribution ◽  
Energy Converter ◽  
Point Absorber ◽  
Device Reliability ◽  
Research Task

Rational exploitation of wave energy makes great contribution to relief the current global energy crisis. Power generation has been taken into the agenda as the main form to utilize wave energy. The point absorber in this paper is simplified to three modules: floater, pontoon and chain. Based on the theory of linear regular wave, the research task of the point absorber is to improve the conversion efficiency and device reliability. This paper researched on the double floater wave energy converter by hydrodynamic numerical calculation, studied the factors that contain the PTO system damping coefficient, wave frequency and the device mass and other factor which can influence the energy conversion efficiency. At last, we found an optimized method for the energy conversion efficiency.

Research on the Hydrodynamic Performance of a Wave Energy Converter

2014 ◽  
Vol 986-987 ◽  
pp. 956-962
Author(s):  
Xiong Bo Zheng ◽  
Yu Nong Yang
Keyword(s):  
Energy Conversion ◽  
Conversion Efficiency ◽  
Wave Energy ◽  
Energy Conversion Efficiency ◽  
High Energy ◽  
Wave Energy Converter ◽  
Hydrodynamic Performance ◽  
Mechanical Transmission ◽  
Energy Converter ◽  
Wave Energy Conversion Efficiency

Under the pressure of fossil energy shortage, rational exploitation of ocean wave energy is propitious to establish an environmentally friendly society. This paper presents the results of a practical research done in a test tank, on the hydrodynamic performance of a wave energy converter with swing arms and floaters designed purposely. Fixed on a trailer, the converter was composed of two floaters, two swing arms, mechanical transmission devices and generators. The method of this research was to measure the floater’s acceleration and the output voltages of the generator under the movement of waves, analysis the influence of wave height and period on floaters’ movement, then compute the wave energy conversion efficiency. At last, the research findings show that the converter performed well with heaving motion performance and high energy conversion efficiency.

scholarly journals Study on Optimum Power Take-Off Torque of an Asymmetric Wave Energy Converter in Western Sea of Jeju Island

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1449
Author(s):  
Haeng Sik Ko ◽  
Sangho Kim ◽  
Yoon Hyeok Bae
Keyword(s):  
Energy Conversion ◽  
Conversion Efficiency ◽  
Wave Energy ◽  
Energy Conversion Efficiency ◽  
Wave Energy Converter ◽  
Jeju Island ◽  
Energy Converter ◽  
Load Torque ◽  
Extracted Power ◽  
Asymmetric Wave

This study primarily investigates an optimum energy conversion efficiency of asymmetric wave energy converter (WEC). A power take-off (PTO) system that provides a constant load torque opposite to pitch motion was implemented. Incident wave conditions were selected based on the measured data in the western sea of Jeju Island, South Korea. An optimum torque was calculated by comparing the time-averaged extracted power with various PTO load torque. InterDyMFoam solver based on Reynolds-averaged Navier-Stokes (RANS) equations were used in an OpenFOAM v4.0 framework—an open-source computational fluid dynamics model—against the experimental results derived from the wave flume. The upward pitch excursion was induced by wave force due to the asymmetric WEC characteristics; however, the downward pitch excursion depends on its weight. Numerically, the PTO torque was only loaded in uni-direction against the upward pitch motion. Moreover, the optimum PTO torque was estimated by comparing the time-averaged extracted power. Finally, the optimum PTO torque was evaluated by an irregular wave as a function of significant wave height. The optimum PTO provides design information about the asymmetric wave energy converter to improve energy conversion efficiency.

scholarly journals Effective Mooring Rope Tension in Mechanical and Hydraulic Power Take-Off of Wave Energy Converter

2021 ◽  
Vol 13 (17) ◽  
pp. 9803
Author(s):  
Ji Woo Nam ◽  
Yong Jun Sung ◽  
Seong Wook Cho
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Mechanical Energy ◽  
Electrical Energy ◽  
Energy Conversion Efficiency ◽  
Wave Energy Converter ◽  
Hydraulic Motor ◽  
Energy Converter ◽  
The Individual ◽  
Conversion Efficiencies

The InWave wave energy converter (WEC), which is three-tether WEC type, absorbs wave energy via moored cylindrical buoys with three ropes connected to a terrestrial power take-off (PTO) through a subsea pulley. In this study, a simulation study was conducted to select a suitable PTO when designing a three-tether WEC. The mechanical PTO transfers energy from the buoy to the generator using a gearbox, whereas the hydraulic PTO uses a hydraulic pump, an accumulator, and a hydraulic motor to convert mechanical energy into electrical energy. The hydraulic PTO has a lower energy conversion efficiency than that of the mechanical PTO owing to losses resulting from pipe friction and the individual efficiencies of the hydraulic pumps and motors. However, the efficiencies mentioned above are not the efficiency of the whole system. The efficiency of the whole system should be analyzed considering the tension of the rope and the efficiency of the generator. In this study, the energy conversion efficiencies of the InWave WEC installed the mechanical and hydraulic PTO devices are compared, and their behaviors are analyzed through numerical simulations. The mechanics of mechanical and hydraulic PTO applied to InWave are mathematically expressed, and the issues of the elements constituting the PTO are explained. Finally, factors to consider for PTO selection are presented.

Numerical Simulation of Wave Energy Converter With Hydrofoil Blades Under Various Wave Conditions

2019 ◽  
Author(s):  
Jie Lei ◽  
Erasmo Gonzalez ◽  
Yingchen Yang ◽  
Ying Zhang ◽  
Ben Xu
Keyword(s):  
Unsteady Flow ◽  
Energy Conversion ◽  
Steady Flow ◽  
Conversion Efficiency ◽  
Wave Energy ◽  
Rotational Speed ◽  
Rotational Velocity ◽  
Ocean Waves ◽  
Energy Conversion Efficiency ◽  
Wave Conditions

Abstract Ocean wave is a rich source of renewable energy with much higher power density than winds. Various WEC technologies have been proposed or are under development. In this study, we developed a 2-dimensional (2D) model and analyzed the rotational motion of the lift-type rotor’s blade under steady flow and unsteady flow. The numerical model was validated by experiments under steady flow. Fast Fourier Transform (FFT) analysis was performed to identify the major contribution of frequency in terms of vortexes generated in the flow field. A comparative study was also performed by comparing all the cases in terms of energy conversion efficiency under different wave conditions. It turns out that the efficiency of energy conversion has a maximum value in the steady flow, while the efficiency for unsteady flow keeps decreasing, therefore this is highly due to the increased dissipation because of the oscillating. When the flow is oscillating, the rotational speed of the rotor under periodic condition is lower than the rotational velocity with steady flow, and a curve fitting was performed in this study to predict the periodic average rotational speed. We conclude that for oscillating flow a minimum of 1.6% energy conversion efficiency can be expected, but it may vary for the actual ocean waves. It is expected the current 2D simulation results can contribute to the wave energy community, especially when the rotor design and optimization is required.

Investigation and Analysis on the Performance of the Oscillating Buoy Wave Power Device under the South China Sea

2013 ◽  
Vol 321-324 ◽  
pp. 1365-1372
Author(s):  
Lai Feng Mao ◽  
Jun Zhang ◽  
Quan You Qu ◽  
Hong Zhou He
Keyword(s):  
South China Sea ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
South China ◽  
Dynamic Characteristics ◽  
Wave Energy ◽  
Energy Conversion Efficiency ◽  
Power Device ◽  
Wave Power ◽  
China Sea

The oscillating buoy wave power device is more effective than other devices in energy conversion efficiency, and now it has been widely applied in development of marine wave energy. The oscillating buoy, which is an important component for the oscillating buoy wave power device, is closely related to energy conversion efficiency. In this paper, considering applying conditions in South China Sea, the dynamic characteristic for oscillating buoy is simulated using AQWA software. By analyzing and comparing dynamic characteristics of several different structure bodies, an optimal structure buoy is obtained and it has better energy conversion efficiency.

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