Design synthesis of oscillating water column wave energy converters: Performance matching

1997 ◽  
Vol 211 (6) ◽  
pp. 489-505 ◽  
Author(s):  
R Curran ◽  
T P Stewart ◽  
T J T Whittaker
Keyword(s):  
Water Column ◽  
Limited Range ◽  
Power Converter ◽  
Analytical Models ◽  
Wave Power ◽  
Oscillating Water Column ◽  
Wells Turbine ◽  
Design Synthesis ◽  
Wave Energy Converters ◽  
Pneumatic Power

The matching of a Wells air turbine to an oscillating water column (OWC) is addressed, with particular reference to design synthesis at the Islay prototype wave power converter. The level of damping applied by the turbine must optimize the hydraulic performance of the OWC in order to facilitate efficient conversion from wave power to pneumatic power. Furthermore, a Wells turbine is only able to convert pneumatic power to mechanical power over a limited range of flow coefficients. Therefore, the efficient operational range of the turbine must extend over a sufficient and optimal proportion of the range of flow coefficients generated by the OWC. Suitable analytical models that describe the behaviour of the system are presented and subsequently the wave conditions and conversion performance at the Islay plant are outlined in order to exemplify the design synthesis to be achieved.

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 Discussion on Optimal Shape for Wave Power Converter Using Oscillating Water Column

2011 ◽  
Vol 23 (5) ◽  
pp. 345-357 ◽  
Author(s):  
Kwang-Ho Lee ◽  
Jung-Hyun Park ◽  
Dong-Jin Baek ◽  
Sung Cho ◽  
Do-Sam Kim
Keyword(s):  
Water Column ◽  
Power Converter ◽  
Optimal Shape ◽  
Wave Power ◽  
Oscillating Water Column

Basic Characteristics of the Primary Conversion of an Oscillating Water Column Type Wave Energy Converter Installed on a Wave-Dissipating Double Caisson

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Tomoki Ikoma ◽  
Koichi Masuda ◽  
Hiroaki Eto ◽  
Shogo Shibuya
Keyword(s):  
Water Column ◽  
Wave Height ◽  
Wave Energy ◽  
Oscillating Water Column ◽  
Type Wave ◽  
Wave Energy Converters ◽  
Column Type ◽  
Fixed Type ◽  
Basic Characteristics ◽  
Pneumatic Power

Several types of oscillating water column (OWC) type wave energy converters (WECs) are researched and developed in the world. They are floating types and fixed types. In case of a fixed type, wave-dissipating caissons could be replaced by WECs of an OWC type. In OWC types, installation of the projecting walls (PWs) is useful in order to improve power take-off (PTO) performance. In this study, a double-dissipating caisson was used as an OWC type WEC with PWs. A front caisson of the double caisson seems to be the area surrounded by PWs and a back caisson can be seen as an OWC. The paper studied the basic property of the primary conversion from wave power to pneumatic power from model tests in a wave tank. It was found that the wave height strongly affects the behaviors of OWC motion and air pressure. Finally, the primary conversion was affected by wave height. Besides, the concept of use of a double caisson was useful for the primary conversion over 80% evaluated using test data.

Water cycle algorithm–based airflow control for oscillating water column–based wave energy converters

2018 ◽  
Vol 234 (1) ◽  
pp. 118-133 ◽  
Author(s):  
Fares M’zoughi ◽  
Soufiene Bouallègue ◽  
Aitor J Garrido ◽  
Izaskun Garrido ◽  
Mounir Ayadi
Keyword(s):  
Power Plant ◽  
Water Column ◽  
Power Plants ◽  
Water Cycle ◽  
Control Strategies ◽  
Wave Power ◽  
Oscillating Water Column ◽  
Wells Turbine ◽  
Water Cycle Algorithm ◽  
Control Approach

The stalling behavior is a feature of the Wells turbine that limits the generated output power of power plants using this turbine. The NEREIDA wave power plant installed in the harbor of Mutriku in the northern Spanish shoreline constitutes an excellent example of this phenomenon. This article deals with the modeling, simulation and control of an oscillating water column unit within the NEREIDA wave power plant. The stalling behavior is investigated and two control strategies are proposed to avoid it. The first control approach is the airflow control which aims to adjust the airflow in the turbine duct using a proportional–integral–derivative controller tuned with the water cycle algorithm. The second control approach is the rotational speed control adjusting the rotor speed using the rotor-side converter of the back-to-back converter which is wired to the doubly fed induction generator. Results of comparative studies show a power generation improvement even relative to the real measured data.

scholarly journals A Model Predictive Control-Based Power Converter System for Oscillating Water Column Wave Energy Converters

Energies ◽  
2017 ◽  
Vol 10 (10) ◽  
pp. 1631 ◽  
Author(s):  
Gimara Rajapakse ◽  
Shantha Jayasinghe ◽  
Alan Fleming ◽  
Michael Negnevitsky
Keyword(s):  
Model Predictive Control ◽  
Water Column ◽  
Predictive Control ◽  
Wave Energy ◽  
Power Converter ◽  
Oscillating Water Column ◽  
Wave Energy Converters ◽  
Energy Converters

Comparison of the performance of oscillating water column devices based on arrangements of water columns

2020 ◽  
Vol 14 (3) ◽  
pp. 7082-7093
Author(s):  
Jahirwan Ut Jasron ◽  
Sudjito Soeparmani ◽  
Lilis Yuliati ◽  
Djarot B. Darmadi
Keyword(s):  
Wave Propagation ◽  
Water Column ◽  
Water Depth ◽  
Graphical Form ◽  
Wave Power ◽  
Oscillating Water Column ◽  
Power Absorption ◽  
Water Columns ◽  
Single Column ◽  
Parallel Arrangement

The hydrodynamic performance of oscillating water column (OWC) depends on the depth of the water, the size of the water column and its arrangement, which affects the oscillation of the water surface in the column. An experimental method was conducted by testing 4 water depths with wave periods of 1-3 s. All data recorded by the sensor is then processed and presented in graphical form. The research focused on analyzing the difference in wave power absorption capabilities of the three geometric types of OWC based on arrangements of water columns. The OWC devices designed as single water column, the double water column in a series arrangement which was perpendicular to the direction of wave propagation, and double water column in which the arrangement of columns was parallel to the direction of wave propagation. This paper discussed several factors affecting the amount of power absorbed by the device. The factors are the ratio of water depth in its relation to wavelength (kh) and the inlet openings ratio (c/h) of the devices. The test results show that if the water depth increases in the range of kh 0.7 to 0.9, then the performance of the double chamber oscillating water column (DCOWC) device is better than the single chamber oscillating water column (SCOWC) device with maximum efficiency for the parallel arrangement 22,4%, series arrangement 20.8% and single column 20.7%. However, when referring to c/h, the maximum energy absorption efficiency for a single column is 27.7%, double column series arrangement is 23.2%, and double column parallel arrangement is 29.5%. Based on the results of the analysis, DCOWC devices in parallel arrangement showed the ability to absorb better wave power in a broader range of wave frequencies. The best wave of power absorption in the three testing models occurred in the wave period T = 1.3 seconds.

Nonlinear 2D analysis of the efficiency of fixed Oscillating Water Column wave energy converters

2014 ◽  
Vol 64 ◽  
pp. 255-265 ◽  
Author(s):  
Yongyao Luo ◽  
Jean-Roch Nader ◽  
Paul Cooper ◽  
Song-Ping Zhu
Keyword(s):  
Water Column ◽  
Wave Energy ◽  
Oscillating Water Column ◽  
Wave Energy Converters ◽  
Energy Converters

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.

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