Experimental Analysis of Flexible Oscillating Water Columns for Wave Energy Conversion

Abstract

This study presents the results of experimental testing for a Flexible Oscillating Water Column (FlexOWC) system, a new wave energy converter designed to enhance energy capture efficiency. The FlexOWC is being developed at Peak Inc., with funding from the US Department of Energy (DOE) under award DE-SC0025144 [1], and is protected under a US provisional patent for its design and innovative features [2]. The experiments, conducted on a 1:20 scale model in a controlled wave flume environment at the Iowa Institute of Hydraulic Research, Hydroscience and Engineering (IIHR) at the University of Iowa, are compared to numerical simulations under regular wave conditions. Orifices are used to simulate the turbine load. Air compressibility modeling [3] has been accounted for while simultaneously satisfying Froude’s scaling criteria for waves using Air Vessels.

Key findings include demonstrating changes in energy absorption when adding the flexible membrane to the oscillating water column. These experiments demonstrate enhanced energy capture compared to rigid OWC designs. These experiments build on methodologies for resolving wave reflections in experimental setups [5] and validate concepts of pulsating power extraction in OWC systems [6]. The paper will discuss critical insights into the dynamic behavior and scalability of the FlexOWC technology, the system’s adaptability to various wave climates, and the impact of membrane characteristics on pneumatic power, with a description of full-scale prototype implementations.