Sea Floor Energy Harvesting

Nagi Elabbasi, Brentan Alexander, and Stuart Brown

Veryst Engineering, Needham, MA, USA

Veryst Engineering has provided design solutions for a variety of industries in the field of energy harvesting. One of their current projects is working on ocean floor sensors, used in naval applications, environmental monitoring, earthquake monitoring, and oil exploration, which presently run on battery-power requiring expensive battery replacement or recharging. Veryst is developing a technology to harvest energy from low speed sea floor ocean currents to power the sensors.

The concept involves converting a steady fluid into an alternating train of vortices that can be directed into an energy conversion device. A bluff body would be placed on the ocean floor and a vane would be inserted downstream from the bluff body and pivoted at its leading edge. This results in an alternating motion in the vane which is then coupled to an electromagnetic generator to produce power.

COMSOL Multiphysics allowed Veryst to model the flow and mechanical motion of the vane to examine the fluid velocity, bluff body geometry, vane geometry, and vane position. The direct input of equations is a unique COMSOL feature that simplified the modeling. The moving mesh feature is another key feature used to update the CFD mesh from deformation in the vane. The simulations predicted the amount of available energy and allowed for design optimization.

Velocity contours for a specific energy harvester configuration