scholarly journals Parametric Study for an Oscillating Water Column Wave Energy Conversion System Installed on a Breakwater

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1926 ◽  
Author(s):  
Hsien Hua Lee ◽  
Cheng-Han Chen
Keyword(s):  
Conversion Efficiency ◽  
Wave Energy ◽  
Oscillating Water Column ◽  
Wave Energy Conversion ◽  
Air Chamber ◽  
Energy Conversion System ◽  
Pneumatic Power ◽  
Caisson Breakwater ◽  
Incident Waves ◽  
Energy Converting

This study focuses on the analysis of the parameters of an oscillating water column (OWC) wave energy conversion system and wave conditions. Interactions between the dimensions of the OWC chambers and wave conditions are all taken into account to design an alternative OWC converter, called caisson-based OWC type wave energy converting system. A numerical method using an unsteady Navier-Stokes equations theorem in conservation form is used to analyze the proposed analytical model. The objective of this study is to try to apply an OWC wave energy converter to a caisson breakwater, which has been constructed in a harbor. The structure proposed in this study is a series of sets of independent systems, in which each set of converters is composed of three chambers to capture the wave energy, while better ensuring the safety of the caisson breakwater. Responses to be analyzed related to the conversion efficiency of the caisson-based OWC wave energy converting system include the airflow velocity from the air-chamber, the pneumatic power and the conversion efficiency in terms of a ratio between the pneumatic power and the energy of the incident waves. Parameters examined in this study include the dimensions of the OWC chamber features such as the orifice of the air-chamber allowing airflow in/output, the chamber length along the direction of incident waves, the size of the opening gate for incident waves and the submersion depth of the air-chamber. As found from the results, a best conversion efficiency from incident waves of 32% can be obtained for the extreme case where the orifice is very small, but for most other cases in the study, the best efficiency is about 15%.

Experimental Performance for a Universal Single Mooring Platform Applied to Wave-Energy Conversion System

2013 ◽  
Vol 385-386 ◽  
pp. 1070-1073
Author(s):  
Hisen Hua Lee ◽  
T.J. Wu
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Water Tank ◽  
Wave Energy Conversion ◽  
Power Generators ◽  
Propagating Waves ◽  
Conversion System ◽  
Energy Conversion System ◽  
Offshore Wave ◽  
Incident Waves

For an offshore platform applied to wave-energy conversion system, in order to catch the maximum waves to generate more powers, similar to wind-energy power generators, a range of angles for the devices normal to the propagating direction of incident waves is required, particularly when the power converting system has directional preference. A single mooring system would allow the offshore wave-energy conversion system to turn freely in accordance to the action of strong directions of propagating waves and in this way, most energy induced from the incident waves can be caught and converted into reusable powers. The aim of this study is to find the efficiency of single-moored platform applied to a wave power converting system through an experimental test in the water tank.

scholarly journals TURBINE−CHAMBER COUPLING IN AN OWC WAVE ENERGY CONVERTER

2012 ◽  
Vol 1 (33) ◽  
pp. 2 ◽  
Author(s):  
Ivan Lopez ◽  
Gregorio Iglesias ◽  
Mario Lopez ◽  
Francisco Castro ◽  
Miguel Ángel Rodríguez
Keyword(s):  
Numerical Modeling ◽  
Water Column ◽  
Wave Energy ◽  
Wave Power ◽  
Optimum Level ◽  
Oscillating Water Column ◽  
Wave Energy Conversion ◽  
Energy Converter ◽  
Air Turbine ◽  
Pneumatic Power

Oscillating Water Column (OWC) systems are one of the most popular technologies for wave energy conversion. Their main elements are the chamber with the water column and the air turbine. When studying the performance of an OWC system both elements should be considered together, for they are effectively coupled: the damping exerted by the air turbine affects the efficiency of the conversion from wave power to pneumatic power in the OWC chamber, which in turn affects the air flow driving the turbine. The optimum level of damping is that which maximizes the efficiency of the conversion from wave to pneumatic power. In this work the turbine-chamber coupling is studied through a combination of physical and numerical modeling.

scholarly journals Structural Safety Analysis for an Oscillating Water Column Wave Power Conversion System Installed in Caisson Structure

2020 ◽  
Vol 8 (7) ◽  
pp. 506
Author(s):  
Hsien Hua Lee ◽  
Thung-Yeh Wu ◽  
Chung-You Lin ◽  
Yung-Fang Chiu
Keyword(s):  
Water Column ◽  
Return Period ◽  
Wave Energy ◽  
Structural Model ◽  
Stokes Equations ◽  
Safety Analysis ◽  
Structural Safety ◽  
Oscillating Water Column ◽  
Caisson Breakwater ◽  
Energy Converting

In this study, an alternative way, a so called caisson based type of oscillating water column (OWC) wave energy converting system was proposed to capture and convert wave energy. Since the caisson structure is constructed to protect the coastal line or ports, it is important to know if a built-in associated OWC system will be a burden to affect the safety of the structure or it is safe enough to work appropriately. In this study, three steps of structural analysis were performed: firstly, the analysis for the structural safety of the whole caisson structure; secondly, performing the mechanic analysis for the chamber of the associated OWC system; and finally, performing the analysis for the wave induced air-pressure in the chamber under the design conditions of a local location during the wave-converting operation. For the structural safety analysis, a typical structural model associated with caisson breakwater was built and analyzed while the shape of the structure, material applied to the construction, and associated boundary conditions were all set-up according to the wave and structures. The motion and the strain distribution of the caisson structure subjected to designated waves of 50-year return period were evaluated and compared to the safety requirement by the code. For the analysis of the energy converting performance, a numerical method by using a theorem of unsteady Navier–Stokes equations in conservation form was used to analyze the proposed OWC model when the structure subjected to an incident wave of a 10-year return period.

A study on the optimal shape of wave energy conversion system using an oscillating water column

2013 ◽  
Vol 165 ◽  
pp. 1663-1668 ◽  
Author(s):  
Sungwon Shin ◽  
Kwang-Ho Lee ◽  
Do-Sam Kim ◽  
Kyu-Han Kim ◽  
Keyyong Hong
Keyword(s):  
Energy Conversion ◽  
Water Column ◽  
Wave Energy ◽  
Optimal Shape ◽  
Oscillating Water Column ◽  
Wave Energy Conversion ◽  
Conversion System ◽  
Energy Conversion System

Wave Energy Conversion Efficiency of the Dual Cylindrical Caisson Breakwaters Embodying an OWC With a Semi-Arc Inlet on Outer Wall

2017 ◽  
Author(s):  
Jing Chen ◽  
Yongxue Wang ◽  
Guoyu Wang ◽  
Li Cai
Keyword(s):  
Energy Conversion ◽  
Conversion Efficiency ◽  
Wave Energy ◽  
Outer Wall ◽  
Energy Conversion Efficiency ◽  
Experimental Investigations ◽  
Wave Energy Conversion ◽  
Air Chamber ◽  
Wave Heights ◽  
Wave Energy Conversion Efficiency

In the paper, the integrated structure of a dual cylindrical caisson embodying an OWC device is designed. The seaside hemi-toroidal column of the dual cylinder caisson is an air chamber for water column oscillation while the leeside hemi-toroidal column of the dual cylinder is filled with sand for caisson stability. Experimental investigations were carried out on the performance of the OWC at different water depths, wave heights and wave periods, as well as on the layout of the caissons and the nozzle area ratio. Experimental results show that the water depth has significant effect on the wave energy conversion efficiency of dual cylindrical caisson breakwaters embodying an OWC. The new structure proposed as a breakwater or revetment structure especially arranged in a one-third convex arc has advantages in collecting more energy and creating a fine landscape environment.

Scale and Configuration Effects of an Airchamber on PTO of Oscillating Water Column Type Wave Energy Converters

2021 ◽  
Author(s):  
Tomoki Ikoma ◽  
Shota Hirai ◽  
Yasuhiro Aida ◽  
Koichi Masuda
Keyword(s):  
Water Column ◽  
Wave Energy ◽  
Water Surface ◽  
Air Pressure ◽  
Scale Model ◽  
Linear Potential ◽  
Oscillating Water Column ◽  
Wave Energy Converters ◽  
Air Chamber ◽  
Energy Converters

Abstract Wave energy converters (WECs) have been extensively researched. The behaviour of the oscillating water column (OWC) in OWC WECs is extremely complex due to the interaction of waves, air, and turbines. Several problems must be overcome before such WECs can be put to practical use. One problem is that the effect of the difference in scale between a small-scale experimental model and a full-scale model is unclear. In this study, several OWC models with different scales and geometries were used in forced oscillation tests. The wave tank was 7.0 m wide, 24.0 m long, and 1.0 m deep. In the static water experiment, we measured the air pressure and water surface fluctuations in an air chamber. For the experiments, models with a box shape with an open bottom, a manifold shape with an open bottom, and a box shape with a front opening, respectively, were fabricated. Furthermore, 1/1, 1/2, and 1/4 scale models were fabricated for each shape to investigate the effects of scale and shape on the air chamber characteristics. Numerical calculations were carried out by applying linear potential theory and the results were compared with the experimental values. The results confirmed that the air chamber shape and scale affect the air pressure fluctuation and water surface fluctuation inside the OWC system.

Design and Analysis of PMSG and PWM Boost Converter for Isolated Ocean Wave Energy Conversion System

2021 ◽  
Author(s):  
Igor Martins dos Santos ◽  
Rodrigo Borges Tavares ◽  
Paulo Roberto Eckert
Keyword(s):  
Energy Conversion ◽  
Wave Energy ◽  
Boost Converter ◽  
Ocean Wave ◽  
Wave Energy Conversion ◽  
Ocean Wave Energy ◽  
Conversion System ◽  
Energy Conversion System
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