Kinematic wearable energy comparison




Ballesteros-Velasco, Nicolas
Garcia, Stephanie
Hood, R. Lyle
Hood, Gold Darr

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Office of the Vice President for Research


The growing consumer demand for sustainable energy has prompted the exploration of alternative energy systems. One technique that has recently been exploited is the harnessing of mechanical vibrations to produce clean, stable, and portable energy. The present research analyses two different methods that harness kinetic energy and convert it to electrical power: piezoelectric and inductive charging. Comparative analysis was conducted through experimentation with two representative designs, wherein the prototypes were attached to a volunteer and the power output was measured during ambulatory movement. It was hypothesized that energy harvesting through inductance would have a higher efficiency and power density than piezoelectrics. The final results exhibited that the piezoelectric converters were more efficient per weight in harvesting energy, refuting the hypothesis and claims from previous studies. The overall power output per weight results demonstrated that piezoelectric strips were the most efficient prototype during participant running with respect to power density, which was measured at 0.553 W/kg. In contrast, the inductance-based prototype had a measured power density of 0.0091W/kg. Piezoelectrics are a more marketable and effective mechanism, due to their greater portability and flexibility in configuration. Electromagnetic inductance suffers by comparison due to design and manufacturing complexity. As the cost associated with piezoelectrics declines, this technology has the potential to build a new market in both attire and charging solutions for handheld devices.