Field Testing a Fluid Flow Energy Harvester with No External Moving Parts*

A novel wind energy harvester with no external moving parts was tested at pilot-scale.  The device incorporates a pair of mirrored foils with 1-meter chord and variable heights up to 3-meters, with the foil suction sides facing inward.  When wind flows over the foils, the resulting suction acts on air-jet orifices on the skins of the foils.  The foils themselves are hollow, and the suction pulls air through the center of the foils and out the air-jets.  This air is supplied by intakes at the bottom of the device.  The internal ducted flow can drive an internal turbine-generator.

Two field test campaigns were completed at the Sandia National Laboratories Scaled Wind Farm Technology (SWiFT) site in Lubbock, Texas.  The incoming wind speed and direction was measured at the height of the device.  Variable chokes were placed at the intakes and the velocity and pressure drop was measured across these, providing a measure of mechanical power.

The influence of off-axis wind direction in both low speed (< 5 m/s) and high speed (~ 10 m/s) conditions is shown, demonstrating the ability of the device to align the flow and maintain power extraction without yaw control.  Results are also compared to previous scaled wind tunnel tests and theory.