Abstract
The rapid depletion of fossil fuel reserves and the growing concerns over environmental sustainability have necessitated the exploration of alternative energy sources. While electromagnetic generators are commonly used in power plants, wind turbines and hydroelectric systems, they are rarely used in smaller scale applications. This is mainly due to size and weight requirements for electromagnetic generators to generate significant electrical power, where the use of a gearbox - to speed-up rotations - is needed in the large-scale applications but restricted in small-scale applications due to size constraints. In addition, fluctuating inputs from intermittent sources (e.g., wind and wave energy) may require the systems relying on electromagnetic generators to have additional power conditioning equipment to maintain a continuous and reliable power supply, such as energy storage systems (e.g., batteries), or back up power sources such as diesel generators.In this context, rotational triboelectric nanogenerators have emerged as a promising solution for revolutionizing the renewable energy landscape. Rotational triboelectric nanogenerators leverage the principles of triboelectricity and electrostatic induction to convert mechanical energy from rotational motion into usable electrical power. They rely on the contact-separation motion between materials with different triboelectric properties to generate electrical charges. And due to their high energy conversion efficiencies, lightweight nature, and compact design, they can be used in various small to large scale applications. Rotational triboelectric nanogenerators are also more adaptable to intermittent power sources due to their direct conversion of mechanical energy into electrical energy (i.e., through the contact and separation of materials with different electron affinities), which allows for conversion to occur at both low and fast rotational speeds. The highly responsive nature of triboelectric nanogenerators allows for the capturing and conversion of the smallest mechanical energy inputs. In addition, environment friendliness is another key factor for the growing popularity of rotational triboelectric nanogenerators, as various choices of sustainable material choices can be made for fabrication, including recycled materials, biodegradable materials, or other materials with low carbon footprint. Furthermore, rotational triboelectric nanogenerators do not contribute to air pollution, greenhouse gas emissions, or the release of any other harmful substances.
This research highlights the potential of rotational triboelectric nanogenerators in transforming two key areas of renewable energy generation: wave energy conversion and drone propeller energy recycling. In the first area of rotational triboelectric nanogenerator application, an automatic watch-inspired wave energy converter was designed and built to overcome challenges that are typically encountered by existing full-scale wave energy converters, such as construction difficulties and location limitations as compared to solar, wind and hydropower energy generating technologies. Besides, most wave energy converters have an adverse effect to the marine environment, as they are normally large in scale, deployed at a distance from the shore and fixed in place with a mooring system intrusive to the seabed, which in turn, disturbs the marine life. This research work is aimed at revolutionizing the design of the rotating mass type of wave energy converters by building small in scale and cost-effective prototype wave energy converters that adopt the energy conversion technologies of self-powered “automatic” hand watches, combined with triboelectric nanogenerators. The prototype device that was designed and built converts kinetic energy from ocean water wave motion into electric energy, just as a self-powered automatic watch converts kinetic energy of the wearer’s arm movements into mechanical or electrical energy that powers the watch. The superior design attributes of the prototype device allow it to convert kinetic energy from waves in all directions and from a wide range of motion frequencies. Moreover, it can produce a peak power density of 304.4 mW/m3 with a matched resistance of 5 GΩ when tested in a wave tank under 2 Hz water wave simulation. This research work also aims to advance nearshore wave energy converter designs that are not moored to the seabed and hence, will have minimal adverse impact to the natural marine environment.
In the second area of rotational triboelectric nanogenerator application, a drone rotational triboelectric nanogenerator was designed and built to recycle the kinetic energy generated from the rotation of a quadcopter drone’s propellor motor. Rotational triboelectric nanogenerators offer a unique approach to energy harvesting in drones by directly utilizing the rotational motion of propeller motors and converting it into useful electrical energy without affecting the aerodynamics, nor the energy consumption of the drone. The drone triboelectric nanogenerator system is intended to act as a supplemental power source for additional drone onboard electronics and thus, hybridizing the drone. This work is first to report a DR-TENG for quadcopter drones, demonstrating its novel design and functionality. The DR-TENG is a co-planar and free-standing mode TENG that can produce a power density of 3.24 W/m2 with a matched resistance of 3 GΩ. The findings from this research work aims to contribute to the advancement of autonomous drone systems by enabling sustainable, self-powered operations, reducing reliance on traditional batteries, and extending flight durations. The application of rotational triboelectric nanogenerators in harvesting and recycling drone propeller energy holds significant potential for revolutionizing the renewable energy landscape in the unmanned aerial vehicle industry.
| Date of Award | 10 Apr 2025 |
|---|---|
| Original language | English |
| Awarding Institution |
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| Supervisor | Walid DAOUD (Supervisor) |
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