The Energy Acquisition System Of Overtopping Wave Energy Convertor(OWEC)

The development and utilization of ocean energy especially wave energy drawmore and more international scholars’ attention. The development and utilization ofwave energy can alleviate present excessive consumption of primary energy sources.Because of wave energy belonging to green energy, that is good for environmentprotection. There are many islands along the coast of China, and offshore islandswhich are far away from the mainland cannot obtain the energy supply. So there isnobody living on these islands, because of the high cost of transporting the resourcesfrom mainland. But this kind of small overtopping wave energy convertor can solvethis problem.This small convertor has characteristics such as large amount of energyconversion, high conversion efficiency, good adaptability etc, with low productioncost, especially suitable for the land far away from the mainland. In this paper, on thebasis of the existing small overtopping wave energy convertor, the innovative usingresonance method is proposed to improve the amount of potential energy conversion,and can use a water turbine more with a bigger waterhead. As we all know, theexisting overtopping wave energy convertor is shore type or firmly anchored to thebottom of the sea, and it can really produce effective power at a certain height.However, because of the existence of tidal, the wave height difference is great, highwaves can completely immersed the convertor, so it will not work at this time. Thispaper adopts resonance type wave energy power generation principle, the convertorwill be as the waves of ups and downs, even there is a tide, it can still provide highpower generation efficiency.The simulation in this paper used two CFD softwares, AQWA and Flow-3D.With joint simulation of these two softwares, it solved the problem that a singlesoftware cannot. First of all, the dimensions of existing small wave energy convertorwere used, only changed the size of the control angle of the gravity center. Resonance simulation by AQWA software got the size of the control angle of the gravity center. The size of the control angle of the gravity center has a great influence, a low one cannot make the system resonance, and it cannot raise the amount of wave energy conversion, however, a high one will cause the overthrow of the convertor and make the system is not stable. So how to get the right size is the main contribution of this paper. And then, Flow-3d software was used to optimize other parameters of the convertor, with the fixed control angle of the gravity center.In this paper, the parameters which have the greatest influence on wave overtopping rate are the freeboard height and the surface slope of the convertor. And other parameters such as submerged depth, diameter, number of grooves etc, belong to auxiliary parameters. Determined the main influence parameters, and then determine the auxiliary parameter, can improve the reliability of the optimization. This paper established the overtopping-discharge hydraulic model, verified that the model can accurately describe the overtopping-discharge situation. Through the comparing of three dimensional simulation and existing convertor, demonstrated that this system can greatly improve its electric energy production.This paper finished the parameter optimization design of overtopping wave energy convertor system, and designed the basic size of overtopping wave energy convertor, combining the bare-foot brother’s work about parameter optimization of discharge system. Followed, the installation and energy storage of the convertor needs further research, to adapt to the request of the commercial.