Design and Efficiency Analysis of a Mechanical Wave Energy Converter

2011 ◽  
Author(s):  
Srinivasan Chandrasekaran ◽  
Harender
Keyword(s):  
Wave Energy ◽  
Energy Resource ◽  
Water Levels ◽  
Wave Energy Converter ◽  
Small Displacement ◽  
Energy Converter ◽  
Mechanical Wave ◽  
Wave Impact ◽  
Heave Motion ◽  
Gear Rack

Wave energy is the most promising natural energy resource that is gaining momentum in the recent years. Successful attempts are made by several researchers to harness wave energy by heave, surge and sway motion of the devices; however no successful commercial model is launched till date leaving this domain as a research potential. Among the proposed technologies, point absorbers are found to be commercially viable to a greater extent primarily due to its simplicity. The present study discusses a new mechanical wave energy converter (MWEC) using point absorber as a wave energy capturing device. Heave motion of a floating buoy due to incident wave field is harnessed to produce power. The conversion takes place in four different stages namely: i) motion of a gear rack, attached to floating buoy results in heave motion; ii) this vertical reciprocating motion is converted to oscillatory rotation of a shaft by a rack and pinion arrangement; iii) alternative rotary motion is converted in to continuous unidirectional rotation using a unidirectional chain assembly; and iv) unidirectional rotation is converted in to other usable energy form. MWEC employs numerous operating advantages over other systems such as: (i) the rack and pinion gear arrangement enabling the buoy to float in line to the changing water levels automatically. (ii) use of RPM multiplier enables rotation of generator shaft at high RPM even for small displacement of float; (iii) the free wheel sprockets of unidirectional chain assembly enable the gear rack to produce a positive upward stroke and a positive downward stroke for every passing wave impact. Further, rpm multiplier shall be easily adjusted to rotate the generator at desired rpm while the whole operation shall be shut down on emergency. The paper presents a detailed analysis of the mechanical system to arrive at the efficiency of the developed MWEC. Based on the studies conducted, it is seen that the overall efficiency of the MWEC is about 19% while maintaining maximum possible efficiency of the mechanical systems involved in the design.

A Study on Development of the Performance Analysis Method of the Floating OWC-WEC Using the MPS Method

2015 ◽  
Author(s):  
Yutaro Sasahara ◽  
Mitsuhiro Masuda ◽  
Kiyokazu Minami
Keyword(s):  
Wave Energy ◽  
Two Phase Flow ◽  
Wave Energy Converter ◽  
Response Analysis ◽  
Phase Flow ◽  
Energy Converter ◽  
Wave Impact ◽  
Two Phase ◽  
Mps Method ◽  
Type Wave

When concrete examination towards utilization is needed, it is necessary to estimate the safety and the performance of a floating Oscillation Water Column (OWC)-type wave energy converter under abnormal oceanographic phenomenon such as large waves, wave impact force, deck wetness and complex motion of mooring system. Therefore, to choose a proper numerical method is important. This present paper describes a fundamental study about estimation of safety and performance of floating OWC-type wave energy converter using the two-phase flow MPS method. In this research, firstly, new algorithm is installed in order to solve problems of the two-phase flow MPS method. Secondly, applicability to an response analysis of a wharf installation type OWC-WEC of the improved MPS method is examined by wave pressure acting to the OWC-WEC and response in the air chamber of the OWC-WEC.

Design and Potential Application of Small Scale Wave Energy Converter

2017 ◽  
Author(s):  
Tunde O. Aderinto ◽  
Francisco Haces-Fernandez ◽  
Hua Li
Keyword(s):  
Wave Energy ◽  
Energy Production ◽  
Energy Resource ◽  
Appropriate Technology ◽  
Wave Energy Converter ◽  
Small Scale ◽  
Ocean Energy ◽  
Energy Converter ◽  
Wave Energy Converters ◽  
Wave Properties

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.

scholarly journals The Economic Feasibility of Floating Offshore Wave Energy Farms in the North of Spain

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 806 ◽  
Author(s):  
Laura Castro-Santos ◽  
Ana Bento ◽  
Carlos Guedes Soares
Keyword(s):  
Wave Energy ◽  
Net Present Value ◽  
Energy Resource ◽  
Economic Feasibility ◽  
Wave Energy Converter ◽  
Energy Converter ◽  
The North ◽  
Cost Of Energy ◽  
Offshore Wave ◽  
North Of Spain

A technique to analyse the economic viability of offshore farms composed of wave energy converters is proposed. Firstly, the inputs, whose value will be considered afterwards in the economic step, was calculated using geographic information software. Secondly, the energy produced by each wave converter was calculated. Then the economic factors were computed. Finally, the restriction that considers the depth of the region (bathymetry) was put together with the economic outputs, whose value depends on the floating Wave Energy Converter (WEC). The method proposed was applied to the Cantabric and Atlantic coasts in the north of Spain, a region with a good offshore wave energy resource. In addition, three representative WECs were studied: Pelamis, AquaBuoy and Wave Dragon; and five options for electric tariffs were analysed. Results show the Wave Energy Converter that has the best results regarding its LCOE (Levelized Cost of Energy), IRR (Internal Rate of Return) and NPV (Net Present Value), and which area is best for the development of a wave farm.

scholarly journals Power Generation Using Mechanical Wave Energy Converter

2012 ◽  
Vol 3 (1) ◽  
pp. 57-70 ◽  
Author(s):  
Srinivasan Chandrasekaran ◽  
Harender
Keyword(s):  
Wave Energy ◽  
Conceptual Development ◽  
Wave Energy Converter ◽  
Experimental Investigations ◽  
Renewable Energy Resources ◽  
Energy Converter ◽  
Mechanical Wave ◽  
Component Level ◽  
Scaled Model ◽  
Effect Analysis

Ocean wave energy plays a significant role in meeting the growing demand of electric power. Economic, environmental, and technical advantages of wave energy set it apart from other renewable energy resources. Present study describes a newly proposed Mechanical Wave Energy Converter (MEWC) that is employed to harness heave motion of floating buoy to generate power. Focus is on the conceptual development of the device, illustrating details of component level analysis. Employed methodology has many advantages such as i) simple and easy fabrication; ii) easy to control the operations during rough weather; and iii) low failure rate during normal sea conditions. Experimental investigations carried out on the scaled model of MWEC show better performance and its capability to generate power at higher efficiency in regular wave fields. Design Failure Mode and Effect Analysis (FMEA) shows rare failure rates for all components except the floating buoy.

Performance Prediction of the Rotational Wave Energy Converter Using Single-Bucket Drag Type Turbine

2014 ◽  
Author(s):  
Hiromichi Akimoto ◽  
YongYook Kim ◽  
Kenji Tanaka
Keyword(s):  
Wave Front ◽  
Wave Energy ◽  
Water Surface ◽  
Numerical Test ◽  
Energy Resource ◽  
Wave Energy Converter ◽  
Rotational Axis ◽  
Energy Converter ◽  
Direction Parallel ◽  
Wave Condition

Because ocean wave propagates along water surface, wave energy resource is measured in the unit of line density (kW/m). It indicates that the output of a Wave Energy Converter (WEC) is proportional to its wave front width when we consider the scaling-up of the device. It will be a problem in the commercialization of a scaled-up WEC because the cost of device increases with size in a higher pace. With the above consideration, the authors proposed a rotary type wave energy converter. It is a drag type vertical axis water turbine with its rotational axis lying horizontally on the water surface and in parallel to the wave front. To capture the orbital fluid particle motion in wave, the turbine is composed of a bucket and a streamlined counter weight. The device can be linearly extended in the direction parallel to the wave front to obtain the merits of scale. The WEC does not have massive components because the reaction torque of electric generation can be absorbed by a relatively small float system. This paper provides the numerical test of the device in deep water wave condition. The dependencies of the output to the wave height and the submergence of the rotational axis are checked by the two-dimensional flow simulation.

scholarly journals Wave-to-Wire Power Maximization Control for All-Electric Wave Energy Converters with Non-Ideal Power Take-Off

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2948
Author(s):  
Sousounis ◽  
Shek
Keyword(s):  
Wave Energy ◽  
Reactive Power ◽  
Energy Resource ◽  
Wave Energy Converter ◽  
Floating Body ◽  
Maximum Efficiency ◽  
Energy Converter ◽  
Electric Wave ◽  
Wave Energy Converters ◽  
Energy Converters

The research presented in this paper investigates novel ways of optimizing all-electric wave energy converters for maximum wave-to-wire efficiency. In addition, a novel velocity-based controller is presented which was designed specifically for wave-to-wire efficiency maximization. In an ideal wave energy converter system, maximum efficiency in power conversion is achieved by maximizing the hydrodynamic efficiency of the floating body. However, in a real system, that involves losses at different stages from wave to grid, and the global wave-to-wire optimum differs from the hydrodynamic one. For that purpose, a full wave-to-wire wave energy converter that uses a direct-drive permanent magnet linear generator was modelled in detail. The modelling aspect included complex hydrodynamic simulations using Edinburgh Wave Systems Simulation Toolbox and the electrical modelling of the generator, controllers, power converters and the power transmission side with grid connection in MATLAB/Simulink. Three reference controllers were developed based on the previous literature: a real damping, a reactive spring damping and a velocity-based controller. All three literature-based controllers were optimized for maximum wave-to-wire efficiency for a specific wave energy resource profile. The results showed the advantage of using reactive power to bring the velocity of the point absorber and the wave excitation force in phase, which was done directly using the velocity-based controller, achieving higher efficiencies. Furthermore, it was demonstrated that maximizing hydrodynamic energy capture may not lead to maximum wave-to-wire efficiency. Finally, the controllers were also tested in random sea states, and their performance was evaluated.

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