Piezoelectric wind power harnessing – an overview

As fossil energy resources deplete, wind energy gains ever more importance. Recently, piezoelectric energy harvesting methods are emerging with the advancements in piezoelectric materials and its storage elements. Piezoelectric materials can be utilized to convert kinetic energy to electrical energy. Utilization of piezoelectric wind harvesting is a rather new means to convert renewable wind energy to electricity. Piezoelectric generators are typically low cost and easy to maintain. This work illustrates an overview of piezoelectric wind harvesting technology. In wind harvesting, piezoelectric material choice is of the first order of importance. Due to their strain rate, robustness is a concern. For optimum energy harvesting efficiency resonant frequency of the selected materials and overall system configuration plays important role. In this work, existing piezoelectric wind generators are grouped and presented in following categories: leaf type, rotary type, rotary to linear type and beam type wind generators

Hybrid Decentralised Energy for Remote Communities: Case Studies and the Analysis of the Potential Integration of Rain Energy

For remote underdeveloped and sparsely populated regions, the use of national power grids to provide electricity can be both unsustainable and impractical. In recent years, decentralised renewable power has gained popularity, endowing social benefits to the local inhabitants through clean rural electrification. However, power reliability and system autonomy are often the primary technical concerns as current systems are largely single source reliant. Hybrid power systems that utilise multiple complementary renewables can help to reduce the dependency on conventional unclean options. A few selected case studies for both single source and hybrid power systems are reviewed, analysing critical success factors and evaluating existing difficulties. The additional integration of the novel rain-powered kinetic-to-electric generator technology to the existing hybrid model is analysed. As with development in general, there is no one-size-fits-all solution to bringing power to remote communities and the most sustainable solution should be found through analysing local resources, environmental conditions and maximising local involvement

Vortex Induced Vibration Energy Harvesting through Piezoelectric Transducers

Harvesting energy from vortex induced vibrations (VIV) in flowing water has the potential to be a low-impact, low-cost alternative to traditional hydropower methods. This project focused on utilizing piezoelectric transducers to transform the VIV oscillations of a cylinder to electrical power. The final prototype successfully produced 0.1 microwatts, but the erratic flow speed of the water and the project’s small scale prevented consistent power generation

Review of nonlinear vibration energy harvesting: Duffing, bistability, parametric, stochastic and others

Vibration energy harvesting typically involves a mechanical oscillatory mechanism to accumulate ambient kinetic energy, prior to the conversion to electrical energy through a transducer. The convention is to use a simple linear mass-spring-damper oscillator with its resonant frequency tuned towards that of the vibration source. In the past decade, there has been a rapid expansion in research of vibration energy harvesting into various nonlinear vibration principles such as Duffing nonlinearity, bistability, parametric oscillators, stochastic oscillators and other nonlinear mechanisms. The intended objectives for using nonlinearity include broadening of frequency bandwidth, enhancement of power amplitude and improvement in responsiveness to non-sinusoidal noisy excitations. However, nonlinear vibration energy harvesting also comes with its own challenges and some of the research pursuits have been less than fruitful. Previous reviews in the literature have either focussed on bandwidth enhancement strategies or converged on select few nonlinear mechanisms. This article reviews eight major types of nonlinear vibration energy harvesting reported over the past decade, covering underlying principles, advantages and disadvantages, and application-specific guidance for researchers and designers

A 3D printed electromagnetic nonlinear vibration energy harvester

A 3D printed electromagnetic vibration energy harvester is presented. The motion of the device is in-plane with the excitation vibrations, and this is enabled through the exploitation of a leaf isosceles trapezoidal flexural pivot topology. This topology is ideally suited for systems requiring restricted out-of-plane motion and benefits from being fabricated monolithically. This is achieved by 3D printing the topology with materials having a low flexural modulus. The presented system has a nonlinear softening spring response, as a result of designed magnetic force interactions. A discussion of fatigue performance is presented and it is suggested that whilst fabricating, the raster of the suspension element is printed perpendicular to the flexural direction and that the experienced stress is as low as possible during operation, to ensure longevity. A demonstrated power of ~25 μW at 0.1 g is achieved and 2.9 mW is demonstrated at 1 g. The corresponding bandwidths reach up-to 4.5 Hz. The system's corresponding power density of ~0.48 mW cm−3 and normalised power integral density of 11.9 kg m−3 (at 1 g) are comparable to other in-plane systems found in the literature