Human-powered Energy Research Articles

A Review of Human-Powered Energy Harvesting for Smart Electronics: Recent Progress and Challenges

Recently, energy harvesting from human motion has attracted substantial research into its ability to replace conventional batteries for smart electronics. Human motion exhibits excellent potential to provide sustainable and clean energy for powering low-powered electronics, such as portable instruments and wearable devices. This review article reports on the piezoelectric, electromagnetic, and triboelectric energy harvesting technologies that can effectively scavenge biomechanical energy from human motion such as, walking, stretching, and human limb movement, as well as from small displacements (e.g., heartbeat, respiration, and muscle movement) inside the human body. Furthermore, various recent designs and configurations of human motion energy harvesters are presented according to their working mechanisms, device compositions, and performances. In order to provide insight into future research prospects, the paper also discusses the limitations, issues, and challenges of piezoelectric, electromagnetic, and triboelectric energy harvesting technologies for the development of smart electronics.

Ionic liquid-based high-voltage flexible supercapacitor for integration with wearable human-powered energy harvesting system

In this work, we report the fabrication of a high-voltage flexible supercapacitor that is able to store energy harvested from a 3D-printed wearable human motion energy harvester and provide power supply to other wearable devices. To bestow the electrode with flexibility, poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) is incorporated with single-walled carbon nanotube (SWCNT) as electrode material, which dramatically decreases its Young’s modulus. Furthermore, the supercapacitor is sandwiched between self-healing layers that protects the device from mechanical failure caused by motion when mounted on the human body as wearable device. Owing to the use of ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4), as the electrolyte, the supercapacitor can be charged up to 2.5 V. This wide electrochemical window, with low equivalent series resistance (ESR), enhances the power and energy densities of the supercapacitor to 11 kW kg− 1 and 23 Wh kg− 1. The device presents excellent flexibility and mechanical durability. We realized a wearable self-powered and self-sustaining system by the integration of the as-prepared supercapacitor with a 3D-printed mechanical energy harvesting knee brace. Harvested energy generated by a tester wearing the system was sufficient to light up an LED light in a demonstration.

Human-Powered Electricity Generation as a Renewable Resource

Energy and human's ability to transform energy into useful work has been the cornerstone of the development of civilizations. Throughout the majority of human existence, we relied solely on metabolic energy derived from plants and animals. In only a few centuries, society has almost completely transformed, from relying on somatic energy to become almost entirely dependent on fossil fuels. The combustion of hydrocarbon energy resources has had detrimental impacts on our environment, which has initiated a push for clean energy. This research study explores the metabolic energy output of humans, specifically within an exercise facility, to evaluate the feasibility of electrical power to be sustained from human-powered energy. Two rowing workouts were evaluated and then compared to solar photovoltaic as an alternative renewable energy. The result of the study demonstrates that 40 members of various physical abilities can collaboratively provide 3–5% of the gym’s average daily electricity demand if converted at an efficiency of 64%. The cost of converting the rowing machines resulted in a 33-year payback period.

Optimizing the Output of a Human-Powered Energy Harvesting System With Miniaturization and Integrated Control

We propose a novel harvesting technology to inconspicuously transduce mechanical energy from human foot-strikes and explore its configuration and control toward optimized energy output. Dielectric elastomers (DEs) are high-energy density, soft material that electrostatically transduce mechanical energy. These properties enable increased energy-transduction efficiency without sacrificing user comfort, if configured and controlled properly. We expose key statistical properties of human gait, which show that an array of miniaturized harvesters across the foot-sole will improve energy output. Further, the gait properties naturally yield a closed-loop control strategy to individually control harvesters in the array in a manner that maximizes net energy output. We propose statistical techniques that guide the configuration and control of the harvester array, and evaluate system behavior from detailed analytical and empirical models of DE behavior. System evaluations based on experimentally collected foot pressure data sets show that the proposed system can achieve up to 120 mJ per foot-strike.

A Compact Human-Powered Energy Harvesting System

Abstract A fully functional, self-sufficient body-worn energy harvesting system is presented in this paper. The system is designed for passively capturing energy from human motion, with the long-term vision of supplying power to portable, wearable, or even implanted electronic devices. Compared with state-of-the-art vibrational systems, the system requires no external power supplies and can bootstrap from zero-state-of-charge to generate electrical energy from walking, jogging, and cycling; convert the induced AC voltage to DC voltage; and then boost and regulate the DC voltage to charge a Li-ion-polymer battery. Measurements show that at open-load the system turns on when the input is above 1 Vpk and turns off when the input drops below about 600 mVpk with no measurable standby power consumption. Tested under normal human activities (walking, jogging, and cycling) when worn on different parts oze body, the 70 cm3 system is shown to charge a 3.7 V rechargeable battery at charge rates ranging from 33 μW to 234 μW.

A compact human-powered energy harvesting system

This paper presents a fully functional, self-sufficient body-worn energy harvesting system for passively capturing energy from human motion, with the long-term vision of supplying power to portable, wearable, or even implanted electronic devices. The system requires no external power supplies and can bootstrap from zero-state-of-charge to generate electrical energy from walking, jogging and cycling; convert the induced ac voltage to a dc voltage; and then boost and regulate the dc voltage to charge a Li-ion-polymer battery. Tested under normal human activities (walking, jogging, cycling) when worn on different parts of the body, the 70 cm3 system is shown to charge a 3.7 V rechargeable battery at charge rates ranging from 33 μW to 234 μW.

Combining eco-design and user benefits from human-powered energy systems, a win–win situation

This paper presents the use of the human body to power electronic products, two product design cases applying human-powered energy systems and the relation with eco-design. The paper illustrated how the use of an alternative energy system (i.e. human-powered energy systems) offers new viewpoints to the design engineer and brings about environmental improvements. ‘Green marketing’ experiences from Philips teach us that environmental benefits should be backed-up by additional user benefits in order to be effective in the market. Human-powered energy systems offer these possibilities.