Study on an Oscillating Water Column Wave Power Converter Installed in an Offshore Jacket Foundation for Wind-Turbine System Part I: Open Sea Wave Energy Converting Efficiency

Abstract

This study is focused on the wave energy converter of an oscillating water column (OWC) system that is integrated with a jacket type infrastructure applied for an offshore wind turbine system. In this way, electricity generation by both wind power and wave power can be conducted simultaneously to maximize the utilization of sustainable energy. A numerical analysis was performed in this research to model and simulate the airflow response and evaluate the converting efficiency of wave energy from an OWC system integrated with an offshore template structural system. The performance of the system including the generating airflow velocity, air-pressure in the chamber, generating power and then the converting efficiency of power from waves are all analyzed and discussed in terms of the variations of the OWC system’s geometrical parameters. The parameters under consideration include the exhale orifice-area of airflow, gate-openings of inflow water and the submerged chamber depth. It is found that from the analytical results the performance of the OWC wave energy converter is influenced by the dimensional parameters along with the design conditions of the local environment. After a careful design based on the in-situ conditions including water depth and wave parameters, an open OWC system can be successfully applied to the template structure of offshore wind power infrastructure as a secondary generating system for the multi-purpose utilization of the structure.

Study on an Oscillating Water Column Wave Power Converter Installed in an Offshore Jacket Foundation for Wind-Turbine System Part II: Experimental Test on the Converting Efficiency

“…The exploration of wave energy has been extensively studied, among which an oscillating water column (OWC) wave energy converting system is the one with relatively higher efficiency. As mentioned in the previous study [2], researches on the OWC-type wave energy converting system still have a very active status, as exemplified by the efforts for energy harvest improvement by changing the shape of a traditional OWC system into a U-OWC [3,4]; as well, some used a backward-bent duct buoy (BBDB-OWC) [5]. The others who aimed to improve the energy harvest ability applied a double-chamber in deep water [6].…”

“…By generally following the associated study [2], this part of the research of an OWC wave energy converting system integrated with an offshore jacket platform was studied experimentally. The purposes of this study will focus on the effectiveness of the OWC system in the open sea, as the one in the study is built on an offshore template structure, and, furthermore, to examine the possibility for improving the effectiveness of the traditional wave converting system.…”

“…It's already been introduced in the analytical study [2] that the OWC wave energy converting system was built right in the space among the legs of an offshore jacket structure so that the air-chamber can be adjusted to allow for an optimum ratio between the outlet orifice and the water surface contained in the chamber. In this study, a scaled down structural model was built basically following the prototype of the previous study, wherein an offshore template structure was meant to be the foundation for a wind turbine system but was installed with an additional OWC wave converting system to extend the utilization of the structure.…”

“…As presented in a recent study [2,19,20], the parameters examined in this experimental study include the dimensions of the OWC chamber, such as the orifice of the air chamber that allows airflow in/output, the size of the opening gate for incident waves, and the submerged depth of the air chamber. All of these parameters are presented in dimensionless form, while wave height and period of waves are considered in a range of variations.…”

A laboratory study on paddle type wave energy converter for transferring seawater using wave energy

“…WEC against dikes was studied by HuaLee et al (2021). They applied vertical walls to boost the function of the WEC by increasing the wave absorption power of the device as waves retreat from the walls.…”