A design and experimental verification methodology for an energy harvester skin structure

This paper presents a design and experimental verification methodology for energy harvesting (EH) skin, which opens up a practical and compact piezoelectric energy harvesting concept. In the past, EH research has primarily focused on the design improvement of a cantilever-type EH device. However, such EH devices require additional space for proof mass and fixture and sometimes result in significant energy loss as the clamping condition becomes loose. Unlike the cantilever-type device, the proposed design is simply implemented by laminating a thin piezoelectric patch onto a vibrating structure. The design methodology proposed, which determines a highly efficient piezoelectric material distribution, is composed of two tasks: (i) topology optimization and (ii) shape optimization of the EH material. An outdoor condensing unit is chosen as a case study among many engineered systems with harmonic vibrating configuration. The proposed design methodology determined an optimal PZT material configuration on the outdoor unit skin structure. The designed EH skin was carefully prototyped to demonstrate that it can generate power up to 3.7 mW, which is sustainable for operating wireless sensor units for structural health monitoring and/or building automation.