Experimental Study of a Fixed OWC-Type Wave Energy Converter with a Heave Plate and V-Shaped Channels for Intermediate-Water-Depth Applications

Abstract

The study of oscillating water column (OWC)-type wave energy converters (WEC) has primarily focused on applications in the nearshore environment with an end use in residential power grids. This study examines the power performance of a new OWC geometry relative to blue economy energy objectives that focus on providing power in the intermediate-water-depth environment. The method examines power performance through the performance indicators of extraction efficiency, coefficient of amplification, and coefficient of pressure. The study discusses the implications of these coefficients relative to a new end use and examines if an analytical relationship between each indicator exists. The power performance is evaluated through experimental testing on a fixed-geometry OWC that consists of a cylindrical OWC chamber affixed above a heave plate with V-shaped channels. In evaluating power performance, the impact of different representative power take-off (PTO) damping values and directional dependence is investigated. It was found that incident wave angle has a minimal impact on extraction efficiency for this geometry and that a relationship exists between extraction efficiency, wave frequency, and PTO damping. It can be concluded that extraction efficiency can be expressed as a function of each coefficient, that an emphasis on extraction efficiency may be misguided for at-sea power applications, and that performance indicators have functionality in OWC design outside of power performance.