Bio-inspired metasurface skin to enhance the performance of blue energy harvesting

Interest in blue energy harvesting systems is rapidly growing and becoming widespread given its promise as a renewable and clean energy source. Blue energy harvesting from raindrop impact would allow low-power systems to operate in remote areas without the need for battery replacement and related maintenance. Insufficient power output is the most critical limitation that makes the conventional types of rain energy harvester (REH) typically unusable or/and infeasible. To overcome this limitation, a bio-inspired metasurface skin is proposed in this paper to serve as the membrane for a piezoelectric type of REHs. The proposed metasurface membrane is comprised of a system of biaxial-cuts inspired by snake scale. The power enhancement of the bio-inspired harvester with a metamembrane was studied and compared to its equivalent conventional harvester with a plain membrane when the substrate was under raindrop pressure. The Finite Element Model (FEM) results showed that the metamembrane could transfer more stress deformation to the piezo-element layer, thus enhancing power output. This is attributable to the metasurface membrane polarizing the PVDF better than a conventional plain membrane because of its higher ability to stretch the PVDF. The proposed bio-inspired harvester could be used for different public facilities such as tents, umbrellas, awnings, temporary roofs, coverings, and tarps to provide power for sensing, lighting, signage, digital displays, etc., especially in heavy-rain regions.