An energy harvesting system includes: a bluff body; and a multilayer stack including piezoelectric layers stacked along a first direction. Each piezoelectric layer includes: a flexible piezoelectric film substrate that extends away from the bluff body along a second direction; an anode that covers a first side of the piezoelectric film substrate; and a cathode that covers a second side of the piezoelectric film substrate. The piezoelectric layers are electrically connected in parallel. The piezoelectric layers are configured to deform in response to a flow of a medium around the bluff body along the second direction.

An irrigation system includes a first valve fluidly-coupled between an inlet pipe and an outlet pipe, and a second valve fluidly-coupled between the inlet pipe and a power harvester. The power harvester generates electrical power at a power output in response to fluid flowing therethrough. An energy storage unit is coupled to the power output to store generated voltage. Comparison circuitry compares the generated voltage to a threshold. Control circuitry causes the second valve to permit fluid to flow therethrough when the generated voltage is less than the threshold, causing generation of the electrical power by the power harvester when the generated voltage is less than the threshold. The comparison circuitry causes the second valve to prevent fluid flow when the generated voltage is at least equal to threshold, ceasing generation of the electrical power by the power harvester when the generated voltage is at least equal to the threshold.

The technology described herein is directed towards resonators that incorporate or are closely coupled to transducers from which energy is harvested. The resonators can be unit cells of a metasurface configured for narrowband sound absorption by phase cancellation of the acoustic wave. Membrane-based transducers such as cymbal harvester transducers can be positioned, e.g., at the neck ports of the resonators, to generate electricity as the air pressure of incoming acoustic waves enters the unit cells. Energy can be harvested from the electricity, and stored for usage and/or used directly to power a device. Such a device powered by the harvested energy can change the resonant frequency of the device, e.g., by changing temperatures in the resonators' air cavities, changing respective dimensions of the respective air cavities, or changing the resonant frequency of the unit cells resonators by changing respective airflow in the respective air cavities.

An irrigation system includes a fluid-inlet, a first fluid-path coupled to the fluid-inlet and having a first valve for controlling fluid-flow, and a second fluid-path coupled to the fluid-inlet and having a second valve for controlling fluid-flow. Fluid flow through a power harvester coupled to the second fluid-path causes generation of electricity. An energy storage device stores the generated electricity. A sensor measures the energy stored in the energy storage device. A controller is coupled to the sensor, the first valve, and the second valve. The controller determines if the stored energy is below a threshold, to open the second valve to allow fluid-flow through the second fluid-path and activate the power harvester when the stored energy is below the threshold, to close the second valve when the stored energy reaches or exceeds the threshold, and to control the first valve independently of the electricity generation to regulate irrigation.

This invention introduces a novel energy conversion system and method that synergistically combines the electrohydraulic and piezoelectric effects to enhance electricity generation efficiency. By leveraging the overunity energy potential of cavitation, the system achieves exceptionally high energy efficiency for producing electrical energy. It features a hermetically sealed container filled with a pressurized dielectric liquid, electrodes connected to a high-voltage power source to induce cavitation, and a geometric shape incorporating piezoelectric material to directly convert energy from pressure shock waves into electricity. This approach uniquely exploits cavitation dynamics to generate sustainable and efficient electrical power, offering a scalable solution adaptable to various applications. The invention has the potential to revolutionize renewable energy systems by providing a cleaner and highly efficient source of electricity.