| Ocean waves represent a valuable green energy resource with the potential to produce all around
the clock unlike solar and wind which are intermittent. Additionally, with over 50% of the US
population living within 50 miles of the ocean, power from the ocean reduces transmission costs.
With this in mind, a promising concept called Submerged Oscillating Water Column (SOWC) is
being studied at Idaho State University (ISU). This study proposes a new prototype design to
increase the efficiency of SOWC devices. A SOWC consists of two submerged vertical pipes
directing the water waves into two submerged chambers that are connected to allow the air to
flow between as waves pass. As waves move over the SOWCs, the hydrostatic pressure
fluctuates, causing the water level inside the chambers to oscillate, which can be converted into
electrical energy using power-take off system. Computational modeling was used to evaluate the
efficiency of the proposed prototype, defined as the conversion ratio of surface waves to waves
in the chambers. Key parameters investigated are wave characteristics, water depth, and the
vertical supply pipe diameter. Results indicate that the optimal diameter of vertical pipe is a
diameter of 50% of the submerged chambers, and conversion rate is increased when oscillating
columns are positioned further apart. Notably, as the wave period increases, efficiency also
increases, ranging from 50% to 99%, approximately 20% improvement over previously proposed
devices. Additionally, a half-cup-shaped modification to the vertical supply pipe improves
velocity head and results in a further 20% efficiency gain mostly on higher wavelength. By
optimizing design parameters and leveraging numerical simulations, this study aims to enhance
SOWC efficiency, paving the way for more effective ocean wave energy harnessing.
Keywords: Submerged Oscillating Water Columns (SOWC), wave energy, conversion ratio |