scholarly journals Harvesting the Waves

2006 ◽  
Vol 128 (12) ◽  
pp. 24-27 ◽  
Author(s):  
Annette von Jouanne

This article elaborates ways of harnessing the power of the ocean. Engineers have attempted, with varying success, to tap ocean energy as it occurs in waves, tides, marine currents, thermal gradients, and differences in salinity. Among these forms, significant opportunities and benefits have been identified in the area of wave-energy extraction. As a form of harvestable energy, waves have advantages not simply over other forms of ocean power, but also over more conventional renewable energy sources, such as the wind and the sun. Wave energy also offers much higher energy densities, enabling devices to extract more power from a smaller volume at consequent lower costs. The Oregon State University (OSU) wave energy team is developing several novel direct-drive prototypes, including buoys that incorporate permanent magnet linear generators, permanent magnet rack-and-pinion generators, and contactless force transmission generators. The OSU researchers are also interested in small-scale wave-energy generators, which could be integrated into boat anchor systems to power a variety of small craft electronic devices.

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2759 ◽  
Author(s):  
Marco Palmieri ◽  
Salvatore Bozzella ◽  
Giuseppe Cascella ◽  
Marco Bronzini ◽  
Marco Torresi ◽  
...  

This work is focused on the design optimization of electrical machines that are used in small-scale direct-drive aerogenerators. A ducted wind turbine, equipped with a diffuser, is considered due to its enhanced power capability with respect to bare turbines. An annular type Permanent Magnet brushless generator is integrated in the turbine structure: the stator coils are placed in the internal part of the diffuser, whereas the permanent magnets are on an external ring connected to the turbine blade tips. Moreover, as regards the stator windings, the Printed Circuit Board (PCB) technology is investigated in order to exploit its advantages with respect to conventional wire coils, such as the increased current density capacity, the reduction of costs, and the enhanced precision and repeatability of the PCBs. An original design procedure is presented together with some scalability rules. An automated tool has been developed in order to aid the electrical machine designer in the first design stages: the tool performs multi-objective optimizations (using the Matlab Genetic Algorithm Toolbox), coupled to fast Finite Element analysis (through the open-source software FEMM) for the evaluation of the electromagnetic torque and field distribution. The proposed procedure is applied to the design of an annular PM generator directly coupled to a small-scale turbine for an urban application.


Energies ◽  
2016 ◽  
Vol 9 (7) ◽  
pp. 487 ◽  
Author(s):  
Ningjun Feng ◽  
Haitao Yu ◽  
Minqiang Hu ◽  
Chunyuan Liu ◽  
Lei Huang ◽  
...  

Author(s):  
Tunde O. Aderinto ◽  
Francisco Haces-Fernandez ◽  
Hua Li

Although theoretical available wave energy is higher than most of ocean energy sources, the commercial utilization of wave energy is much slower than other ocean energy sources. The difficulty of integration with the electrical grid system and the challenges of the installation, operation and maintenance of large energy generation and transmission systems are the major reasons. Even though there are successfully tested models of wave energy converters, the fact that wave energy is directly affected by wave height and wave period makes the actual wave energy output with high variation and difficult to be predicted. And most of the previous studies on wave energy and its utilization have focused on the large scale energy production that can be integrated into a power grid system. In this paper, the authors identify and discuss stand-alone wave energy converter systems and facilities that are not connected to the electricity grid with focus on small scale wave energy systems as potential source of energy. For the proper identification, qualification and quantification of wave energy resource potential, wave properties such as wave height and period need to be characterized. This is used to properly determine and predict the probability of the occurrence of these wave properties at particular locations, which enables the choice of product design, installation, operation and maintenance to effectively capture wave energy. Meanwhile, the present technologies available for wave energy converters can be limited by location (offshore, nearshore or shoreline). Therefore, the potential applications of small scale stand-alone wave energy converter are influenced by the demand, location of the need and the appropriate technology to meet the identified needs. The paper discusses the identification of wave energy resource potentials, the location and appropriate technology suitable for small scale wave energy converter. Two simplified wave energy converter designs are created and simulated under real wave condition in order to estimate the energy production of each design.


2015 ◽  
Vol 793 ◽  
pp. 363-367
Author(s):  
Mohd. Aizuddin Firdaus Mohmad Hamim ◽  
Taib Ibrahim ◽  
Nursyarizal Mohd Nor

Malaysia is a small country surrounded by numerous oceans that can provide sufficient renewable energy for utilization. This work is to propose a design and modeling of a portable linear permanent magnet generator for the Wave Energy Conversion system that suits with the local wave parameters. Linear generator is preferable as compared to the rotary generator due to the direct drive technology that promises low maintenance cost. Three linear permanent magnet generator designs with different types of permanent magnet layout have been proposed as the permanent magnet used can provide better flux density compared to other topologies. Preliminary results for the air gap flux distribution and open-circuit flux distribution are demonstrated and discussed are shown to be as expected.


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