Oscillating-water-column wave energy converters and air turbines: A review

https://pure.hw.ac.uk/ws/files/22688902/Ning_Zou_OWC_Exp_Revision2_AppledEnergy2016.pdf

An experimental investigation of hydrodynamics of a fixed OWC Wave Energy Converter

The control and simulation of the power delivered to the grid are becoming an important topic, particularly when the number of distributed power generation systems increases. In this paper, two different control schemes for an oscillating-water-column Wells-turbine-generator module are simulated, implemented, and compared. In the first method, the control system does appropriately adapt the slip of the induction generator according to the pressure drop entry in order to maximize the generated power, while in the second method, a traditional proportional-integral-derivative-based control is implemented in order to deal with the desired power-reference-tracking problem. It will be shown how the controllers avoid the stalling behavior and that the average power of the generator fed into the grid is significantly higher in the controlled cases than in the uncontrolled one while providing the desired output power.

Modeling and Simulation of Wave Energy Generation Plants: Output Power Control

"Comprehensive Renewable Energy" is the only multi-volume reference work of its type at a time when renewable energy sources are seen increasingly as realistic alternatives to fossil fuels. As the majority of information published for the target audience is currently available via a wide range of journals, seeking relevant information (be that experimental, theoretical, and computational aspects of either a fundamental or applied nature) can be a time-consuming and complicated process. "Comprehensive Renewable Energy" is arranged according to the most important themes in the field (photovoltaic technology; wind energy technology; fuel cells and hydrogen technology; biomass and biofuels production; hydropower applications; solar thermal systems: components and applications; geothermal energy; ocean energy), and as such users can feel confident that they will find all the relevant information in one place, with helpful cross-referencing between and within all the subject areas, to broaden their understanding and deepen their knowledge. It is an invaluable resource for teaching as well as in research. Available online via SciVerse ScienceDirect and in print. Editor-in Chief, Professor Ali Sayigh (Director General of WREN (World Renewable Energy Network) and Congress Chairman of WREC (World Renewable Energy Congress, UK) has assembled an impressive, world-class team of Volume Editors and Contributing Authors. Each chapter has been painstakingly reviewed and checked for consistent high quality. The result is an authoritative overview which ties the literature together and provides the user with a reliable background information and citation resource. The field of renewable energy counts several journals that are directly and indirectly concerned with the field. There is no reference work that encompasses the entire field and unites the different areas of research through deep foundational reviews. "Comprehensive Renewable Energy" fills this vacuum, and can be considered the definitive work for this subject area. It will help users apply context to the diverse journal literature offering and aid them in identifying areas for further research. Research into renewable energy is spread across a number of different disciplines and subject areas. These areas do not always share a unique identifying factor or subject themselves to clear and concise definitions. This work unites the different areas of research and allows users, regardless of their background, to navigate through the most essential concepts with ease, saving them time and vastly improving their understanding. There are more than 1000 references from books, journals and the internet within the eight volumes. It is full of color charts, illustrations and photographs of real projects and research results from around the world. The only reference work available that encompasses the entire field of renewable energy and unites the different areas of research through deep foundational reviews. Allows readers, regardless of their background, to navigate through the most essential concepts with ease, saving them time and vastly improving their understanding.

Comprehensive Renewable Energy

The purpose of this paper is to introduce the status of wave energy conversion (WEC) technologies from a different perspective. Past studies based on WEC systems are summarized and classified in terms of WEC system components to clearly reveal the performance, efficiency and development of WEC technologies over the last two decades. It has been proved that the individual components of a WEC system, such as types of wave energy converter and generator motion, control methods and power electronic converter, have a close relationship with each other and that no single component can be optimized without considering the others. It can be helpful to divide into descriptive parts to provide a better understanding of the development process for WEC technologies so that studies based on WEC technologies are discussed by regarding types of wave energy converters, generators, control methods, controller applied sides, waves, power electronic converters and validations and publication year in this paper.

Control, power and electrical components in wave energy conversion systems: A review of the technologies

A twin unidirectional impulse turbine topology for OWC based wave energy plants

A twin unidirectional impulse turbine topology for OWC based wave energy plants – Experimental validation and scaling

Oscillating water column (OWC) based wave energy plants have been designed with several types of bidirectional turbines for converting pneumatic power to shaft power. Impulse turbines with linked guide vanes and fixed guide vanes have been tested at the Indian Wave Energy plant. This was after initial experimentation with Well’s turbines. In contrast to the Well’s turbine which has a linear damping characteristic, impulse turbines have non-linear damping. This has an important effect in the overall energy conversion from wave to wire. Optimizing the wave energy plant requires a turbine with linear damping and good efficiency over a broad range of flow co-efficient. This work describes how such a design can be made using fixed guide vane impulse turbines. The Indian Wave Energy plant is used as a case study.

Performance estimation of bi-directional turbines in wave energy plants

Backward Bent Duct Buoy (BBDB) is a type of oscillating water column (OWC) wave energy converter invented by Masuda. BBDB is said to have superior primary conversion efficiency with maintaining small mooring costs. However, some problems remain unclear with the relationship between body shape and its motions in addition to the primary conversion efficiency and its motions. A number of physical tests for five different BBDB models were carried out in this research. From these experimental results, the effects of BBDB hull shape and the primary conversion efficiency were obtained. Furthermore, methods for obtaining incident wave components and for obtaining the responses of BBDB induced by the incident waves using the experimental results of BBDB are proposed.

Effects of Hull Shape on Primary Conversion Characteristics of a Floating OWC ”Backward Bent Duct Buoy”

In order to design a floating OWC-type wave energy converter such as Backward Bent Duct Buoy (BBDB), it is necessary to make clear the optimal hull shape which maximizes the generating electrical energy. In this paper, we have carried out two and three dimensional wave tank tests to obtaine the optimal hull shape of BBDB. Firstly, to make clear the effect of the length of the horizontal duct to the primary conversion efficiency, we have carried out two dimensional tank tests for three types of BBDB models. Secondly, we have investigated the effect of the duct length to the draft on the primary conversion efficiency by means of two types of BBDB models. Thirdly, we have investigated the effect of the direction of incident waves on the primary conversion efficiency. Finally, the three dimensional effect on the primacy conversion efficiency is investigated by comparing the difference between two dimensional tank tests and three dimensional tank tests.

Shuichi Nagata

Papers

A twin unidirectional impulse turbine topology for OWC based wave energy plants

A twin unidirectional impulse turbine topology for OWC based wave energy plants – Experimental validation and scaling

Performance estimation of bi-directional turbines in wave energy plants

Effects of Hull Shape on Primary Conversion Characteristics of a Floating OWC ”Backward Bent Duct Buoy”

Primary Energy Conversion Characteristics of a Floating OWC “Backward Bent Duct Buoy”