Low Cost and Piezoelectric based Soft Wave Energy Harvester

MRS Advances ◽  
2019 ◽  
Vol 4 (15) ◽  
pp. 889-895
Author(s):  
Sina Baghbani Kordmahale ◽  
Jitae Do ◽  
Kuang-An Chang ◽  
Jun Kameoka

Abstract:Wave energy converters have been developed and commercialized in past decades; they have now faced numerous challenges of large volume sizes, environmental hazards, and high costs of deployment, components and maintenance. To address these challenges and make a wave energy converter practically available for various applications at a reasonable cost, we have developed a soft wave energy harvester that integrated low-cost soft material structures and piezoelectric-based Macro Fiber Composite (MFC). This integrated soft wave energy converter has a straightforward fabrication process and structure that can harvest energy from a broad working frequency of waves. The innovative design combined low-cost and commercially available materials and formed a harvester that addressed the aforementioned problems of commercially available harvesters. Additionally, the low cost and simple design are scalable for large energy conversion in the future. The energy conversion performance of the proposed platform has been investigated in a wave flume with low-frequency incoming waves (<2Hz). The soft energy conversion platform is hung like a curtain and produces a maximum 487nW. Also, the low cost and durable encapsulation can protect the electrical properties of MFCs and circuits, and a single harvester can last through all experiment steps without any degradation, which was more than 170 hours.

2005 ◽  
Vol 128 (1) ◽  
pp. 56-64 ◽  
Author(s):  
Gaelle Duclos ◽  
Aurelien Babarit ◽  
Alain H. Clément

Considered as a source of renewable energy, wave is a resource featuring high variability at all time scales. Furthermore wave climate also changes significantly from place to place. Wave energy converters are very often tuned to suit the more frequent significant wave period at the project site. In this paper we show that optimizing the device necessitates accounting for all possible wave conditions weighted by their annual occurrence frequency, as generally given by the classical wave climate scatter diagrams. A generic and very simple wave energy converter is considered here. It is shown how the optimal parameters can be different considering whether all wave conditions are accounted for or not, whether the device is controlled or not, whether the productive motion is limited or not. We also show how they depend on the area where the device is to be deployed, by applying the same method to three sites with very different wave climate.


Author(s):  
Pedro C. Vicente ◽  
Anto´nio F. O. Falca˜o ◽  
Paulo A. P. Justino

Floating point absorbers devices are a large class of wave energy converters for deployment offshore, typically in water depths between 40 and 100m. As floating oil and gas platforms, the devices are subject to drift forces due to waves, currents and wind, and therefore have to be kept in place by a proper mooring system. Although similarities can be found between the energy converting systems and floating platforms, the mooring design requirements will have some important differences between them, one of them associated to the fact that, in the case of a wave energy converter, the mooring connections may significantly modify its energy absorption properties by interacting with its oscillations. It is therefore important to examine what might be the more suitable mooring design for wave energy devices, according to the converters specifications. When defining a mooring system for a device, several initial parameters have to be established, such as cable material and thickness, distance to the mooring point on the bottom, and which can influence the device performance in terms of motion, power output and survivability. Different parameters, for which acceptable intervals can be established, will represent different power absorptions, displacements from equilibrium position, load demands on the moorings and of course also different costs. The work presented here analyzes what might be, for wave energy converter floating point absorber, the optimal mooring configuration parameters, respecting certain pre-established acceptable intervals and using a time-domain model that takes into account the non-linearities introduced by the mooring system. Numerical results for the mooring forces demands and also motions and absorbed power, are presented for two different mooring configurations for a system consisting of a hemispherical buoy in regular waves and assuming a liner PTO.


Author(s):  
Eirini Katsidoniotaki ◽  
Edward Ransley ◽  
Scott Brown ◽  
Johannes Palm ◽  
Jens Engström ◽  
...  

Abstract Accurate modeling and prediction of extreme loads for survivability is of crucial importance if wave energy is to become commercially viable. The fundamental differences in scale and dynamics from traditional offshore structures, as well as the fact that wave energy has not converged around one or a few technologies, implies that it is still an open question how the extreme loads should be modeled. In recent years, several methods to model wave energy converters in extreme waves have been developed, but it is not yet clear how the different methods compare. The purpose of this work is the comparison of two widely used approaches when studying the response of a point-absorber wave energy converter in extreme waves, using the open-source CFD software OpenFOAM. The equivalent design-waves are generated both as equivalent regular waves and as focused waves defined using NewWave theory. Our results show that the different extreme wave modeling methods produce different dynamics and extreme forces acting on the system. It is concluded that for the investigation of point-absorber response in extreme wave conditions, the wave train dynamics and the motion history of the buoy are of high importance for the resulting buoy response and mooring forces.


Author(s):  
Yi-Hsiang Yu ◽  
Ye Li ◽  
Kathleen Hallett ◽  
Chad Hotimsky

This paper presents a recent study on the design and analysis of an oscillating surge wave energy converter (OSWEC). A successful wave energy conversion design requires balance between the design performance and cost. The cost of energy is often used as the metric to judge the design of the wave energy conversion (WEC) system, which is often determined based on the device’s power performance; the cost of manufacturing, deployment, operation, and maintenance; and environmental compliance. The objective of this study is to demonstrate the importance of a cost-driven design strategy and how it can affect a WEC design. A set of three oscillating surge wave energy converter designs was analyzed and used as examples. The power generation performance of the design was modeled using a time-domain numerical simulation tool, and the mass properties of the design were determined based on a simple structure analysis. The results of those power performance simulations, the structure analysis, and a simple economic assessment were then used to determine the cost-efficiency of selected OSWEC designs. Finally, we present a discussion on the environmental barrier, integrated design strategy, and the key areas that need further investigation.


2016 ◽  
Vol 693 ◽  
pp. 484-490
Author(s):  
Ying Xue Yao ◽  
Hai Long Li ◽  
Jin Ming Wu ◽  
Liang Zhou

Duck wave energy converter has the advantages of high conversion efficiency, simple construction, low cost relative to other wave power device. In the paper, the numerical simulation of the response of the converter was calculated by the AQWA software which based on the three dimensional potential flow theories. The results show that the pitch angle appear the peak when the incident wave frequency is 1rad/s and the maximum of the pitch angle come out as the linear wave normally incident the duck body, which means duck wave energy converter can absorb more wave energy in this angular frequency. The above research can provide reference for the design of the duck wave energy converter.


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.


2016 ◽  
Vol 22 (2) ◽  
pp. 71 ◽  
Author(s):  
Masjono Muchtar ◽  
Salama Manjang ◽  
Dadang A Suriamiharja ◽  
M Arsyad Thaha

To date there were few research on the effect of non-linearity properties of the ocean waves on the performance of wave energy converter (WEC), which uses a series of unidirectional gear. One such parameter is the variation of wave period. The influence of wave period variations on the performance of physical model of the wave energy converters have been investigated at the Hydraulics Laboratory, Department of Civil Engineering, Hasanuddin University Indonesia. This WEC physical model was fabricated and assembled at Politeknik ATI Makassar Indonesia. The investigation steps consists of physical model development, physical model investigation at wave flume prior to the wave period  variation, measuring input output parameters of the physical model under test and empirical model formulation based on observed data analysis. Physical model test carried out on the wave flume at the Hydraulics Laboratory of the Department of Civil Hasanuddin University, at a water depth of 25 cm, wave height between 5-9 cm and wave period between 1.2 - 2.2 seconds. Investigation result based on flywheel radial speed (RPM) and torque (Nm) indicated that calculated harvested power was inversely proportional with the wave period. The longer the period of the waves, the energy produced is getting smaller. The derived empirical formula was y = -85.598x + 208.53 and R² = 0.8881. Y is energy produced (Watt) and X is the wave period (Second). Formulations generated from this study could be used as a reference for future research in dealing with wave period variations on a design one way gear wave energy converter as a source of renewable energy.


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