Design Of Energy Harvester Research Articles

High Roughness Induced Pearl Necklace‐Like ZIF‐67@PAN Fiber‐Based Triboelectric Nanogenerators for Mechanical Energy Harvesting

AbstractTechnological developments and innovations in the wearable device field have created huge consumer demand. Hence, designing energy harvesting devices are of utmost importance. Of the various types of energy harvesting devices, triboelectric nanogenerators (TENGs) have come to the fore, as it can efficiently harvest electrical energy from mechanical motions. To date, polymers and metals have dominated the triboelectric series, but there is a need to develop novel composite materials and 2D materials to enhance the performance of TENGs. In this study, electrospun polyacrylonitrile nanofibers are prepared and decorated with zeolitic imidazole framework‐67 (ZIF‐67@PAN) to form pearl‐necklace‐like fibers. ZIF‐67@PAN nanofibers are prepared by immersing PAN nanofibers for different hours (1, 5, 10, and 24 h) in ZIF‐67 solution, they provide more roughness, and efficient surface contact area. The immersion of PAN fibers in ZIF solution for longer times increases overall energy harvesting efficiency. Different amounts of MXene are deposited on PVDF; the inclusion of MXene improves the charge transfer properties of TENGs. PAN@ZIF‐67 is used as a positive tribolayer and PVDF@MXene as a negative tribolayer. The optimized TENG device has 305 V, 10.6 µA, and 10.9 W/m2 power and demonstrated promising energy harvesting characteristics and self‐powered sensing efficiency.

A transition point: Assistance magnitude is a critical parameter when providing assistance during walking with an energy-removing exoskeleton or biomechanical energy harvester.

Researchers and engineers have developed exoskeletons capable of reducing the energetic cost of walking by decreasing the force their users' muscles are required to produce while contracting. The metabolic effect of assisting concentric and isometric muscle contractions depends, in part, on assistance magnitude. We conducted human treadmill experiments to explore the effects of assistance magnitude on the biomechanics and energetics of walking with an energy-removing exoskeleton designed to assist eccentric muscle contractions. Our results demonstrate that the assistance magnitude of an energy-removing device significantly affects the energetics, muscle activity, and biomechanics of walking. Under the moderate assistance magnitude condition, our device reduced the metabolic cost of walking below that of normal walking by 3.4% while simultaneously producing 0.29 W of electricity. This reduction in the energetic cost of walking was also associated with an 8.9% decrease in hamstring activity. Furthermore, we determined that there is an assistance magnitude threshold that, when crossed, results in the device transitioning from assisting to hindering its user. This transition is marked by significant increases in muscle activity and the metabolic cost of walking. These results could aid in the future design of exoskeletons and biomechanical energy harvesters, as well as adaptive control systems, that identify user-specific control parameters associated with minimum energy expenditure.

Design of crosstalk aware energy harvesting system-on-chip

A crosstalk noise aware design methodology is developed, suitable for advanced energy harvesting systems-on-chip (SoCs). The proposed methodology enables accurate substrate crosstalk modeling via process characterization, Python based layout extraction and RC modeling, providing a reliable design flow for robust integrated circuits (IC) implementation. The SoC’s noise coupling performance degradation is accurately estimated, co-calculating the impact of the package and printed-circuit-board (PCB) design. The proposed design flow is seamlessly integrated into the standard design suite. An energy harvesting SoC is used as a product level vehicle. The system is developed in a 0.18 μm CMOS process. The noise aggressor is a digital Maximum Power Point Tracking (MPPT) block, while the noise victim is a DC-DC boost converter and the input voltage sensor. The proposed crosstalk design flow effectively captures the hardware efficiency values, with 14.6% maximum deviation from experimental results, while the standard methodology presents high deviation up to 51.08%.

Design of RF energy harvester for 700 MHz

Abstract Radio frequency energy harvester is the conversion of ambient radio frequency electromagnetic waves into usable electrical energy, powering low-power devices without traditional power sources. In this paper, a novel RF energy harvester is proposed for 700 MHz frequency band. For the purpose of rectification, a Greinacher voltage rectifier cum multiplier is used in the circuit and Schottky Diode HSMS-2852 is used for implementing a rectifier. The LC impedance matching is implemented to improve the circuit performance of the harvester including conversion efficiency and output voltage. Simulation of the rectifier is done using the PathWave Advanced Design System (ADS) software. The rectifier shows the optimized performance at 5 kΩ load impedance. Simulation results show the highest efficiency of 33.1 % and an output voltage of 3.2 V with 8 dBm RF power at 700 MHz input frequency.

A novel two-degree-of-freedom nonlinear piezoelectric energy harvester with a stopper for broadband low-frequency vibration

Energy conversion efficiency and operation bandwidth are two main concerns in piezoelectric energy harvesting in low-frequency vibration environments. This paper presents a compact two-degree-of-freedom nonlinear piezoelectric energy harvester (2DOF NPEH) with a stopper. The proposed harvester consists of an elastic beam, a piezoelectric beam with tip mass, a pair of repulsive magnets, and a mechanical stopper. A bistable configuration is established through magnetic interaction. This study investigates the generating characteristics of the 2DOF NPEH under frequency-sweep excitation, utilizing a rigid stopper (RS) and different elastic stoppers (ESs). The experimental results indicate that the implementation of a mechanical stopper in a NPEH contributes to widening the operation bandwidth and enhancing the peak voltage. As the stiffness of the stopper increases, the bandwidth gradually shrinks while the peak voltage increases. The optimal energy conversion efficiency depends on the stiffness of the ES, and it occurs when the wire diameter of the spring is 1.2 mm. Compared with the 2DOF NPEH without a stopper, the utilization of a RS results in a 13.85-fold increase in the bandwidth of the generator at the first resonance. Moreover, the maximum absolute voltage is 12.82 times and 3.47 times the output voltage of the 2DOF NPEH at the first and second resonance, respectively. This work offers valuable insights into the design and optimization of piezoelectric energy harvesters in practical applications.

Design and Piezoelectric Energy Harvesting Properties of a Ferroelectric Cyclophosphazene Salt.

Cyclophosphazenes offer a robust and easily modifiable platform for a diverse range of functional systems that have found applications in a wide variety of areas. Herein, for the first time, it reports an organophosphazene-based supramolecular ferroelectric [(PhCH2 NH)6 P3 N3 Me]I, [PMe]I. The compound crystallizes in the polar space group Pc and its thin-film sample exhibits remnant polarization of 5µCcm-2 . Vector piezoresponse force microscopy (PFM) measurements indicated the presence of multiaxial polarization. Subsequently, flexible composites of [PMe]I are fabricated for piezoelectric energy harvesting applications using thermoplastic polyurethane (TPU) as the matrix. The highest open-circuit voltages of 13.7V and the maximum power density of 34.60µWcm-2 are recorded for the poled 20wt.% [PMe]I/TPU device. To understand the molecular origins of the high performance of [PMe]I-based mechanical energy harvesting devices, piezoelectric charge tensor values are obtained from DFT calculations of the single crystal structure. These indicate that the mechanical stress-induced distortions in the [PMe]I crystals are facilitated by the high flexibility of the layered supramolecular assembly.

Design and implementation of sustainable solar energy harvesting for low-cost remote sensors equipped with real-time monitoring systems

Data acquisition systems, such as Wireless Smart Sensor Networks (WSSNs) can increase the resilience of infrastructure by providing real-time monitoring and data collection of environmental parameters. Yet, sustainable energy supplies for sensor networks established in remote and inaccessible areas still present a challenge. Previously, researchers have attempted to address this difficulty by proposing different energy systems including solar energy harvesting, however, significant prolonged experimental data for the operation of extensive networks powered by solar energy has not been reported. This paper presents an original design and implementation of an energy system for a large WSSN and provides the sensors' power status data over a significant duration. A network of low-cost flood monitoring sensors, including twenty-six water level sensors, twenty rain gauges, and eight communication nodes were deployed and tested on summer and fall 2022 at six remote locations at the northern New Mexico Pueblo, Ohkay Owingeh. A thermometer and a humidity sensor were added to each communication node to record temperature and air's moisture level. In addition, a networked voltage monitoring system was deployed to observe the sensors energy status in real-time. The items of the WSSN are composed of two differing energy circuits suited for their energy demands. The sensors' energy circuits contain a photovoltaic panel, a lithium-polymer battery, a control device, and a DC-to-DC converter. Whereas the communication nodes contain another photovoltaic panel, a lead-acid battery, and a solar charging controller. The findings provide a perspective on the long-term field deployment of WSSNs consisting of low-cost sensors.

Optimisation-driven design of sliding mode triboelectric energy harvesters

With the increasing demand of emerging technologies for autonomous sensing, the modelling and optimisation of complete energy harvesting systems are essential to achieve efficient power output. To date, most of the optimisation efforts in enhancing the performance of triboelectric energy harvesters have been focused on the improvement of material properties and on the establishment of figures of merit to assist in the definition of parameters. However, these efforts do not consider the complex relationship between the device structure and power output, physical constraints in place, and varying excitation conditions. This paper fills that gap for the first time by applying an optimisation algorithm to establish mechanisms for optimisation-driven design of sliding-mode triboelectric energy harvesters. A global optimisation methodology is developed to improve its performance, having experimentally validated the numerical model adopted. This work highlights the need for a more robust design framework for applications of triboelectric energy harvesting and proposes a hybrid approach combining the finite element method with analytical models to consider different energy harvesting parameters including the degradation of the charge transfer efficiency due to the edge effect. A novel high-power output sliding-mode triboelectric energy harvesting concept is proposed and its performance is optimised, using the proposed methodology.

Self-Powered wireless sensor node based on RF energy harvesting and management combined design

Environmental energy-harvesting technologies, such as solar, vibration, and radio frequency (RF) energies, can effectively increase the lifespan of wireless sensor nodes while reducing their size, weight, and cost. Generally, RF energy harvester design methods are based on ideal energy sources and resistive loads, whereas real RF energy conversion and management are extremely complex and cannot be verified using conventional design methods. In this study, an RF energy harvesting and management combined design method is proposed to attain the requisite output parameters of an RF energy harvester to enable load operation during the design phase. Based on the proposed method, a highly integrated high-performance RF energy-harvesting wireless sensor node (RF-EH WSN) is constructed. The experimental results indicate that the input energies for both the simulation and measurements are equal and consistent (-10 dBm) for identical expected output voltages and energies. The proposed WSN can achieve self-powered operation at a distance of 13.5 m from a 27 dBm RF energy source.

Optimization of elastic wave propagation in a reconfigurable medium by genetic algorithms with adaptive mutation probability

We introduce a reconfigurable medium for the manipulation of elastic propagation properties of Lamb waves. It is based on a shape memory polymer (SMP) with temperature-dependent Young’s modulus. Waves are excited by a laser pulse and detected by a laser vibrometer. A two-dimensional temperature field is controlled by a scanning heating laser. We use genetic algorithms to determine optimal distributions of mechanical properties for the following criteria: the wave amplitude has to be maximized at a given location and at the same time minimized at one or two other locations. Due to the reconfigurability of the medium, the optimization process is performed directly on the object of optimization, and not on a numerical or analytical representative, based on a direct measurement of the fitness. The optimized configuration makes the waves propagate away from (or around) the point of minimization towards the point of maximization. We improve the genetic algorithm by adapting the mutation probability of individual genes according to specific criteria, which depend on the surrounding genes (distributed in two dimensions). This provides the advantages: concentrating the mutations in the areas of genetic inconsistencies and counterbalancing the error of the fitness measurement. The method is applicable for the intelligent design of wave energy harvesters, ultrasonic transducers, and analogue wave computing devices.

Gradience Free Nanoinsertion of Fe3O4 into Wood for Enhanced Hydrovoltaic Energy Harvesting.

Hydrovoltaic energy harvesting offers the potential to utilize enormous water energy for sustainable energy systems. Here, we report the utilization and tailoring of an intrinsic anisotropic 3D continuous microchannel structure from native wood for efficient hydrovoltaic energy harvesting by Fe3O4 nanoparticle insertion. Acetone-assisted precursor infiltration ensures the homogenous distribution of Fe ions for gradience-free Fe3O4 nanoparticle formation in wood. The Fe3O4/wood nanocomposites result in an open-circuit voltage of 63 mV and a power density of ∼52 μW/m2 (∼165 times higher than the original wood) under ambient conditions. The output voltage and power density are further increased to 1 V and ∼743 μW/m2 under 3 suns solar irradiation. The enhancement could be attributed to the increase of surface charge, nanoporosity, and photothermal effect from Fe3O4. The device exhibits a stable voltage of ∼1 V for 30 h (3 cycles of 10 h) showing good long-term stability. The methodology offers the potential for hierarchical organic-inorganic nanocomposite design for scalable and efficient ambient energy harvesting.

Non-transient optimum design of nonlinear electromagnetic vibration-based energy harvester using homotopy perturbation method

Abstract In this paper the coupled differential equations governing the vibration of nonlinear electromagnetic energy harvesters are solved by the homotopy perturbation method. The amplitudes of odd harmonics of displacement of the magnet, coil current, and load voltage are derived up to the 5th harmonic. The frequency response of output power is plotted and it peaks at the linear mechanical resonance frequency. It should be noted that the optimum design of coil and load parameters, optimum electromagnetic coupling coefficient, and optimum vibration frequency of the magnet attached to a non-linear spring resulted in a stationary or non-transient vibration. Paying insufficient attention to this point and using typical parameters instead of optimum ones will result in transient vibration. The research aims at a rigorous semi-analytical method on a nonlinear problem which has previously solely investigated by numerical or experimental method.

Active shaping of a bi-stable potential: Exploring nonlinear coupling to a stiff externally-excited oscillator

The ability to actively shape the potential energy function of a bi-stable oscillator without the use of feedback control offers key advantages in the design of adaptive morphing structures, mechanical switches, vibration absorbers, and energy harvesters. In this paper, we propose an approach based on nonlinearly coupling the bi-stable (low-frequency) oscillator to a stiff (high-frequency) linear oscillator, which, in turn, is excited harmonically near its resonant frequency. We show that active and controlled shaping of the potential energy function can be achieved by changing either the magnitude and/or the frequency of the high-frequency harmonic input. Pronounced shape changes are achieved even for relatively small levels of the input excitation; levels that are much lower than those needed when the bi-stable oscillator is directly subjected to the high-frequency excitation. The study also reveals an interesting phenomenon where the effective potential energy function of the slow dynamics can transition from the bi- to the mono-stable type and vise versa by simply changing the initial conditions of the externally-excited stiff oscillator.

Design and experimental analysis of low wind speed rotary piezoelectric energy harvester

Design and experimental analysis of low wind speed rotary piezoelectric energy harvester

In-depth understanding of boosting salinity gradient power generation by ionic diode

Ionic diodes constructed with asymmetric channel geometry and/or charge layout have shown outstanding performance in ion transport manipulation and reverse electrodialysis (RED) energy collection, but the working mechanism is still indistinct. Herein, we systematically investigated RED energy conversion of straight nanochannel-based bipolar ionic diode by coupling the Poisson-Nernst-Planck and Navier-Strokes equations. The effects of nanochannel structure, charging polarity, and symmetricity as well as properties of working fluids on the output voltage and output power were investigated. The results show that as high-concentration feeding solution is applied, the bipolar ionic diode-based RED system gives higher output voltage and output power compared to the unipolar channel RED system. Under optimal conditions, the voltage output of the bipolar channel is increased by ∼100% and the power output is increased by ∼260%. This work opens a new route for the design and optimization of high-performance salinity energy harvester as well as for water desalination.

Improving energy harvesting from low-frequency excitations by a hybrid tri-stable piezoelectric energy harvester

This paper presents the design of a novel hybrid tri-stable piezoelectric energy harvester (HTPEH) that improves the energy harvesting efficiency of piezoelectric energy harvesters operating at low frequencies. The proposed HTPEH is an extension of a conventional tri-stable cantilever piezoelectric energy harvester with an elastic base (TPEH + EB), and it incorporates vertical and rotational elastic amplifiers that are installed between the mass block at the left end of a cantilever beam and the left side of a U-shaped frame to enhance the system's nonlinear characteristics. By utilizing Hamilton's principle, a HTPEH's nonlinear electromechanical equation is formulated, and the harmonic balance method is used to obtain analytical solutions for the displacement amplitude, voltage amplitude, and power amplitude. The study investigates the effects of various parameters, including the elastic amplifier-to-base stiffness ratio and elastic amplifier-to-piezoelectric cantilever beam mass ratio on the energy harvesting performance of the HTPEH. The results indicate that the displacement and voltage amplitude of the HTPEH exhibit two peaks as the external excitation frequency increases, and adjusting the relative mass and stiffness between the elastic amplifier and the piezoelectric cantilever beam can alter the frequency band interval where the two response peaks of the system are located. This allows the HTPEH to enter inter-well motion at low-level external excitation, resulting in high output power. The HTPEH outperforms the TPEH + EB in terms of energy harvesting efficiency under low-frequency environmental excitation.

Prototype Design of Radio Frequency Energy Harvesting for Lighting Applications

The prototype resonant frequency is designed to work at 150 MHz. The signal source prototype is the signal that comes from handy talky (HT). There are two subsystems, which are Matching Impedance and Voltage Multiplier. The resonant frequency of the matching impedance subsystem at 143 MHz from 0.053 mH inductor and 0.0233 pF capacitor. The output of the matching impedance subsystem is then amplified by the multiplier voltage subsystem using parallel PH4148 diodes with the 6-stage multiplier. Load prototype is a CR-151 LED that works at 12 volts 1 watt. When the HT battery has a voltage of 7.3 volts, the prototype can turn on the lamp with the distance between the TX antenna and the antenna on the prototype less than 36 cm. The maximum voltage on the load is 6.8 volts with a length of 5 cm between the antenna and the lamp 774 lumen.

Energy harvesting using linear type magnetostrictive transducer for real-time application

Economic and social development of nations across the globe is demanding enormous need for energy and power resources. Energy production using safe and renewable sources can aid in mitigating the release of greenhouse gases and avoiding the devastating climate changes. In the present case, a linear type magnetostrictive transducer device is designed by employing Terfenol-D magnetostrictive rods for renewable energy harvesting application. A linear device was designed with two Terfenol-D rods, three permanent magnets (neodymium magnets), springs, and primary and secondary coils. Terfenol-D rod crystallizes in cubic Laves phase and exhibits the saturation magnetostriction value of 1242 × 10−6 at the field of 2.5 kOe. An equivalent circuit is constructed for the induced magnetic flux in the designed transducer device. Frequency and wave form dependent output voltage is examined in the designed energy harvesting device. A square wave at the applied frequency of 2200 Hz (100 mA current) produces a maximum output voltage of 4.91 V. Sine and triangle waves produce 3.38 and 2.82 V, respectively, at 1700 and 1600 Hz. The induced voltage is sufficient to ignite the light emitting diode. A linear type magnetostrictive transducer can be employed as a potential renewable energy source for real-time application with moderate output voltage.

Optimization and Validation of Piezoelectric Cantilever Designs for Energy Harvesting from Bridge Vibrations

This study proposes an optimization strategy for bridge applications with a vibration-based energy harvester design. Piezoelectric cantilevers with multiple degrees of freedom (DOF) are designed and optimized to match resonant frequencies with the vibration frequencies of a full-scale bridge structure under different loading conditions and measurement locations. The specific optimization procedures include bridge vibration acceleration measurement, simulation model development for estimating the resonant frequencies, a regression model for optimization of mass combinations, and final installation on the full-scale bridge for validation. The results show that the simulation model predicted the resonant frequencies of cantilevers with less than 1 Hz difference compared with laboratory measurements. Following the entire optimization procedures proposed in this study, the optimized 2-DOF and 3-DOF cantilevers were capable of generating 18.9 [Formula: see text] J and 23.4 [Formula: see text] J energy under one loading pass, respectively, which were significantly higher than those from the baseline designs. The feasibility of the proposed optimization strategy was demonstrated and validated for vibration-based energy harvesting from bridge structures.

Design and construction of a foam-based piezoelectric energy harvester

Generating, converting, harvesting and storing energy are crucial parts of society. This work aims to design and construct a piezoelectric generator that harvests energy from pressure to produce an output voltage capable of charging and powering low-energy electronic devices such as mobile phones and 5 V light bulbs. Proteus 8.0 professional software is used to simulate the circuit for construction. A piezoelectric disc transducer, which is the principal component, was used in the construction. The result shows a voltage of 5–12 V capable of powering low-voltage electronic devices. Amidst the constant instability in electric power systems in Nigeria, those in rural areas have little or no electricity access. Electronic and communication devices are necessary to connect community members to those outside their communities and the world wide web for global information. Children and youths require lighting facilities at school and home for further studies. The design will provide an alternative for energy supply to areas with little or no access to electricity.