Harvesting Technology Research Articles

Improving On-farm Energy Use Efficiency by Optimizing Machinery Operations and Management: A Review

AbstractThe energy use and emissions from direct fossil fuel combustion on-farms to power farm machinery was critically reviewed. Approximately, 15% of agricultural production costs on-farm are energy-related. A potential solution to more sustainable energy use is a shift toward biofuels from renewable resources. The reduction of greenhouse gas emissions through the substitution of diesel oil with biodiesel depends on the feedstock, the inter-esterification process, the storage period, and ambient conditions. In modern tractors, increased fuel use efficiency (or reduced fuel consumption) has been achieved by power/load matching and the use of variable transmission. Engine management systems that are capable of continuously communicating with the engine and transmission to make appropriate adjustments based on inputs received from the tractor allow for quick and precise responses to changing conditions. As a result, maximum efficiency and productivity can be obtained from the tractor operating similarly to the traditional ‘gear-up and throttle-back’ methods of a proficient operator. The future for autonomous tractors is promising, though not new. Electric-powered tractors are near to commercialization or are already commercially available. Hybrid electric driven tractors present some advantages in terms of increased energy use efficiency and functionalities. Increased efficiency can lead to a reduction in diesel fuel consumption and hence, a concurrent decrease in CO2 emission. Where the local electricity supply has a low-carbon emission factor, this can also result in significant emission reductions. Small light-weight robotic equipment can potentially perform functions currently undertaken by tractor-drawn and other heavy equipment with high-fuel consumption, provided field operating capacity was not compromised. However, the size and weight limitations inherent in current harvesting and transport technology mean that soil compaction will still be a problem with robotic units. The robotic operation of medium-scale equipment within a precision-controlled traffic farming environment should offer more feasible and energy-efficient alternatives.

A Pulsed Bubble‐Driven Efficient Liquid‐Solid Triboelectric Nanogenerator

AbstractHarnessing energy from underwater bubbles has garnered significant attention, particularly for powering off‐grid circuitry. However, the efficiency of bubble‐driven liquid‐solid interface charge transfer remains low. This research unveils a phenomenon: accelerated bubble slippage enhances liquid‐solid interfacial charge transfer. Building upon this discovery, a pulse bubble‐based power generation technique is proposed, achieving an energy density of 24.2 mJ L−1 generated by pulsed bubbles. The crux of pulse bubble power generation lies in the precise control of impact velocity. By meticulously regulating the impact kinetic energy of bubbles, the accumulated potential energy of multiple small bubbles is converted into instantaneous pulse kinetic energy. A typical pulse bubble is controlled within a 72 ms timeframe, unleashing a surge of energy that can directly illuminate 400 light‐emitting diodes. This approach represents a groundbreaking advancement in underwater energy harvesting technology, dramatically expanding its potential applications.

Rainwater harvesting technologies in arid plains of Argentina: small local strategies vs. large centralized projects

Access to water has been and remains one of humanity’s greatest challenges. Especially in arid plains exposed to significant climatic fluctuations and future global change trends. In the past and present, local communities of the arid plains of central-western Argentina (i.e., Guanacache Lagoons, Cuyo region) have developed multiple strategies to manage water supply problems. The aims of this study are: i) to characterize the different water harvesting technologies (pre-Hispanic and modern) used, and ii) to compare the small local strategies of water harvesting (bottom-up solutions) with the large centralized projects (top-down solutions). On the one hand, we show the transformations of these technologies over time, and the challenges faced by inhabitants in the context of climate change trends. On the other hand, we analyze the role of the state through hydraulic policies and projects implemented by the provincial states over the last two centuries and how this impacted the study area. This review is based on a historical and archaeological bibliography, and recent publications about the region, including articles based on our ethnographic fieldwork. Our results demonstrate the valuable experience accumulated by local populations in water harvesting methods, particularly in areas where groundwater is deep and saline, and shows the adaptability of these technologies in contexts of increasing scarcity. We considered that local indigenous knowledge can largely contribute to the sustainable management of water resources. This study might be useful for decision-makers and water managers in drylands around the world to find and equitable approach that combines technical advances with local knowledge.

Cantilever configurations in vibration-based piezoelectric energy harvesting: a comprehensive review on beam shapes and multi-beam formations

Abstract Vibration-based energy harvesting technology is a well-established research area that has attracted tremendous interest over the last decade. This interest is primarily owing to its extension into a wide range of engineering domains, particularly in microelectromechanical systems. The cantilever beam is the most common and widely used model for vibration-based energy harvester, driven by two key factors: (a) simplicity in design, and (b) high output power density. Numerous studies over the years have focused on optimizing the cantilever beam design to increase output power capacity and/or widen the frequency bandwidth of the harvester. While researchers have proposed a plethora of cantilever beam configurations for specific purposes (e.g. low-frequency harvesting, multi-directional frequency harvesting, etc), there is a notable lack of detailed literature on the types and configurations of cantilever beams. This gap hinders researchers from gaining a comprehensive understanding of the cantilever beams already introduced. Following the need, in this article a comprehensive review is made to list the types of cantilever beams proposed by the researchers over the years. This review covers the working principles of piezoelectric energy harvesting, analyses existing solutions geared towards increasing power output and widening working frequency, and discusses diverse configurations including single and multiple beam setups. The listed beams are categorized based on their structural shape and organization such that it can be helpful for a reader to anticipate which cantilever beam design can be suitable for a specific need. Power output capacity and operating frequency for every beam design are also presented in a tabular form, under each beam category. This would enable the researchers to tailor their designs for specific applications, enhance material efficiency, drive innovation, and open new application possibilities.

A Systematic Review of Techno-Economic, Environmental and Socioeconomic Assessments for Vibration Induced Energy Harvesting

There is a growing need to ensure the resilience of energy and water systems through digitalization, retrofit these systems for cleaner energy systems, and protect public safety in terms of water quality. This resilience requires a reliable power supply that could be provided by harnessing unexploited energy hidden in the current water infrastructure through the deployment of vortex-induced vibration energy harvesters. Therefore, being able to understand the feasibility of deploying these devices across technical, socioeconomic and environmental scales could further enhance successful deployment and integration of these devices. This paper aims to provide a systematic review investigating the development of energy harvester technologies to understand the key methods used to assess their application feasibility. This study used the PRISMA guidelines, and 139 articles were reviewed and synthesized. The trends were visualized, illustrating the current direction in energy harvesting development and application and methods used to assess the feasibility of these devices and technology. The majority of the reviewed studies focused on technical feasibility, design configuration, limitation, and identification of the most optimal application environment. The results revealed a huge opportunity for energy harvesters, especially as a power supply for monitoring sensors. Nevertheless, the results also identified a knowledge gap when it comes to assessing the overall application feasibility of energy harvesting as most studies currently neglect economic feasibility, environmental impacts, social aspects and energy resilience. Assessment tools will help fill this knowledge gap by identifying the key barriers and benefits gained from integrating this technology into existing energy systems and water systems.

A high-performance ultra-compact plasmonic metamaterial structure for optical THz absorption

This study presents the design and analysis of a high-performance metamaterial absorber for the optical terahertz (THz) regime. The proposed absorber utilizes a unique nested flower-shaped structure composed of nickel (Ni) and silicon dioxide (SiO2), achieving an average absorption exceeding 97.91% with a broad bandwidth of 1320 THz (180 THz − 1500 THz). A unit cell size of 66 nm × 66 nm × 24 nm makes this design highly attractive for miniaturized devices. Strong absorption originates from localized surface plasmon resonance (LSPR), where light interacts with the electrons on the Ni surface. Notably, the design maintains excellent absorption performance even at oblique incident angles up to 60° with polarization insensitivity. These results highlight the Ultra-Compact Plasmonic Metamaterial (UCPM) absorber’s potential for diverse applications due to its broad spectral response, high absorption efficiency, and minimal footprint, making it valuable for energy harvesting, infrared imaging, and electromagnetic stealth technologies.

Wood Harvesting Practices, Technologies and Safety Considerations in Small-Scale Private Forests in Uganda

Wood Harvesting Practices, Technologies and Safety Considerations in Small-Scale Private Forests in Uganda

Bimodal Droplet-Based Electricity Generation Through Semi Cassini Oval Dynamic Morphology Control.

Droplet-based electricity generator (DEG) is the promising energy harvesting technology applicable in versatile scenarios. Despite numerous optimizations in DEG's materials and structures, few has paid attention to the droplet dynamics and morphology control. Here the droplet's spread-retraction dynamics and the resultant semi Cassini oval (SCO) morphology are reported, characterized by convex at both ends and concave in the middle. The lifted top electrode (LTE) is designed to respond to the dynamic SCO morphology in two steps: 1) LTE first contacts the leading edge of the spreading droplet, generating a negative voltage peak; 2) LTE second contacts the trailing edge of the retracting droplet, generating a positive voltage peak. In this way, bimodal electrical output is obtained, which exhibits 25% increase in peak-to-peak voltage and 33% increase in average power compared to the traditional DEG with only one voltage peak. These results prove that incorporating the droplet dynamics and morphology control into DEG design uplifts the energy harvesting limit from individual droplet. The proposed LTE-DEG inspires alternative route for DEG power enhancement by maximizing energy utilization of individual droplet from the perspective of droplet dynamic morphology design.

Stability and bifurcation analysis of a 2DOF dynamical system with piezoelectric device and feedback control

This study aims to demonstrate the behaviors of a two degree-of-freedom (DOF) dynamical system consisting of attached mass to a nonlinear damped harmonic spring pendulum with a piezoelectric device. Such a system is influenced by a parametric excitation force on the direction of the spring’s elongation and an operating moment at the supported point. A negative-velocity-feedback (NVF) controller is inserted into the main system to reduce the undesired vibrations that affect the system’s efficiency, especially at the resonance state. The equations of motion (EOM) are derived by using Lagrangian equations. Through the use of the multiple-scales-strategy (MSS), approximate solutions (AS) are investigated up to the third order. The accuracy of the AS is verified by comparing them to the obtained numerical solutions (NS) through the fourth-order Runge-Kutta Method (RK-4). The study delves into resonance cases and solvability conditions to provide the modulation equations (ME). Graphical representations showing the time histories of the obtained solutions and frequency responses are presented utilizing Wolfram Mathematica 13.2 in addition to MATLAB software. Additionally, discusses the bifurcation diagrams, Poincaré maps, and Lyapunov exponent spectrums to show the various behavior patterns of the system. To convert vibrating motion into electrical power, a piezoelectric sensor is connected to the dynamical model, which is just one of the energy harvesting (EH) technologies with extensive applications in the commercial, industrial, aerospace, automotive, and medical industries. Moreover, the time histories of the obtained solutions with and without control are analyzed graphically. Finally, resonance curves are used to discuss stability analysis and steady-state solutions.

Exploring Co2TiRE (RE = Nd and Tb) as a promising shape memory alloy using DFT methods

Our study employs self-consistent ab-initio calculations using highly precise spin-polarized density functional theory with both GGA and GGA+U approaches, coupled with the Boltzmann transport scheme. This comprehensive approach investigated the structural stability, magneto-electronic behavior, thermophysical characteristics, and thermoelectric transport properties of Co2TiRE (RE = Nd, Tb) Heusler alloys. Through structural optimizations, we confirm that these materials exhibit ferromagnetic behavior. Analysis of band occupation and density of states using GGA and GGA+U methods reveals that both compounds are metallic in both spin configurations. We evaluated key transport properties such as the Seebeck coefficient, electrical and thermal conductivity and the figure of merit to understand their potential in thermoelectric applications. Conservative estimates of the Seebeck coefficient and the figure of merit suggest promising applications in thermoelectric energy harvesting technologies. Additionally, we provide a comprehensive analysis of the thermophysical behavior, including the Debye temperature, thermal expansion, and specific heat, to assess the alloys thermodynamic stability across varying temperature and pressure conditions.

Impact of Hydrochloric Acid Doping on Polyaniline Conductivity and Piezoelectric Performance in Polyaniline/Bismuth Oxyiodide Nanocomposites

This study investigates the impact of hydrochloric acid (HCl) doping, ranging from 0.2 M to 1.25 M, on the conductivity of polyaniline (PANI) and the piezoelectric performance of polyaniline/bismuth oxyiodide (PANI/BiOI) nanocomposites (NCs). Two distinct methods for fabricating NCs based on PANI and bismuth oxyiodide (BiOI) are proposed. Two distinct methods for fabricating PANI/BiOI NCs are proposed, and their optical and electrical properties are systematically examined. The direct allowed energy bandgap of the NCs is found to be approximately 1.9 eV. The piezoelectric performance, attributed to the 2D Janus structure of BiOI, is explored in detail, with the bulk piezoelectric coefficient measured at 1.43(65) pm/V. Sensitivity to pressure interaction reached 21.1(92) mV/bar, and the generated power was 5.09 nW for air pressure excitation in a composite consisting of 37.5 wt% BiOI and 62.5 wt% PANI doped with 0.2 M HCl, fabricated in-situ. The results demonstrate precise control over key parameters, including the fabrication method, sample thickness, HCl doping concentration, and BiOI content, highlighting the significant potential for enhancing nanogenerator functionality. These findings provide valuable insights into improving the performance of piezoelectric materials for energy harvesting technologies.

A Synergistically Enhanced Triboelectric-Electromagnetic Hybrid Generator Enabled by Multifunctional Amorphous Alloy for Highly Efficient Self-Powered System.

Triboelectric-electromagnetic hybrid generator (TEHG) has emerged as an effective technology for mechanical energy harvesting. However, the independent operation of triboelectric nanogenerator (TENG) and electromagnetic generator (EMG), along with tribo-materials wear and magnetic field divergence, constrain the device's overall performance. To address these challenges, a synergistically enhanced TEHG (SE-TEHG) is proposed based on the multifunctional amorphous alloy. Following detailed material analyses, Fe72Si8B20 is selected as the synergistic layer for its low surface roughness, high Vickers-hardness, amorphous structure, and high magnetization. Compared to Al, this material not only boosts TENG's output current and current retention rate by 28.75% and 85.24%, but also improves EMG's output power by 51.05%. In constructing a self-powered system with TEHG, a significant impedance discrepancy exists between the energy harvester (with matched impendence of 16 MΩ for TENG and 110 kΩ for EMG) and the application end. Without power management circuits, the demonstrated self-powered variable impedance system achieves an energy utilization efficiency that is 2.98 times greater than the conventional constant impedance system. The integration of multifunctional materials to realize strong-coupling hybrid generators, combined with the customization of variable impedance systems, set a milestone in efficient mechanical energy harvesting and utilization.

Charge Generation and Enhancement of Key Components of Triboelectric Nanogenerators: A Review.

The past decade has witnessed remarkable progress in high-performance Triboelectric nanogenerators (TENG) with the design and synthesis of functional dielectric materials, the exploration of novel dynamic charge transport mechanisms, and the innovative design of architecture, making it one of the most crucial technologies for energy harvesting. High output charge density is fundamental for TENG to expand its application scope and accelerate industrialization; it depends on the dynamic equilibrium of charge generation, trapping, de-trapping, and migration within its core components. Here, this review classifies and summarizes innovative approaches to enhance the charge density of the charge generation, charge trapping, and charge collection layers. The milestone of high charge density TENG is reviewed based on material selection and innovative mechanisms. The state-of-the-art principles and techniques for generating high charge density and suppressing charge decay are discussed and highlighted in detail, and the distinct charge transport mechanisms, the technologies of advanced materials preparation, and the effective charge excitation strategy are emphatically introduced. Lastly, the bottleneck and future research priorities for boosting the output charge density are summarized. A summary of these cutting-edge developments intends to provide readers with a deep understanding of the future design of high-output TENG.

Triboelectric Nanogenerator Based on Tin Doped Zinc Oxide and Polyvinyl Alcohol Composite Thin Film for Energy Harvesting Applications

The triboelectric nanogenerator (TENG) collects mechanical energy from its surroundings and converts it to electrical signals that can be used in sustainable energy harvesting technologies to help maintain the social ecosystem. However, TENG operation with pure triboelectric material may not be sufficient to power a small electronic system without modification. The optimal material capable of producing significant electrical energy with flexible structures remains a major barrier to practical application. In this study, tin-doped zinc oxide (Sn:ZnO) and polyvinyl alcohol (PVA) composite thin films were prepared using a simple solution immersion technique at various Sn atomic percentage (at.%) concentrations for use in TENG devices. The crystalline quality of a composite thin film made of Sn:ZnO and PVA was identified using x-ray diffraction. The microstructure changes of the composite thin film were found to be influenced by Sn doping, as studied using optical microscopy. The TENG with 2.5 at.% Sn:ZnO/PVA composite thin film and Kapton film achieved the highest peak voltage of 8.5 V in open circuit and 90 µW output power at 1 MΩ. The produced electrical output was then used to store energy in capacitors. According to its TENG properties, the Sn:ZnO/PVA composite thin film-based TENG has the potential to be used in low power electronic devices.

Significantly Enhanced Output Performance of Triboelectric Nanogenerators via Charge Storage and Release Strategy.

As a novel energy harvesting technology, bettering the output performance of triboelectric nanogenerators (TENGs) is vital. Although quite a number methods to increase charge density have been proposed, challenges such as high impedance matching and low output current persist, severely limit the energy utilization efficiency of TENGs. Here, a new power management circuit (PMC) is proposed that through charge storage and release strategy. This circuit first excites the surface charge of the TENG using the charge excitation circuit, and then releases the stored charge through a self-triggered switch. Compared to a standard TENG, the output current of the TENG with this PMC is increased by a factor of 1108, the impedance is decreased from 100 MΩ to 10 kΩ, and the energy utilization efficiency is markedly improved. This work affords a reference for enhancing the output performance of TENG, reducing impedance, and broading the utility attainable of TENGs.

Optimization of microalgal-bacterial consortium flocculation through chitosan-diatomite composite materials: A sustainable approach to biomass harvesting

Chitosan-based flocculants are emerging as a promising technology for microalgae harvesting. However, the implementation of cost-effective and sustainable chitosan-inorganic composites within algal-bacterial symbiosis (ABS) systems for harvesting microalgal-bacterial consortiums (MBC) is still underdeveloped. This study addresses this gap by synthesizing and evaluating chitosan-diatomite composite materials (CTS/DTE), with a focus on their concentration impact on MBC flocculation. Optimal biomass production and flocculation performance were achieved at a CTS/DTE concentration of 60 mg/L during MBC co-culture. Comprehensive characterizations revealed that the largest particle size significantly contributed to superior flocculation efficiency. This efficacy was primarily attributed to the synergistic effects of net trapping and adsorption cross-linking, facilitated by the unique interaction between CTS and DTE. These interactions not only enhanced the bond between the flocculant and microalgal cells but also promoted the structural stabilization of the MBC flocs. Additionally, tryptophan-like proteins in the extracellular polymeric substances (EPS), as identified through three-dimensional fluorescence (EEM) analysis, were found to be the primary contributor to the hydrophobic properties of MBC flocs, significantly enhancing their adhesion and aggregation thermodynamics. Collectively, this research elucidates innovative strategies and provides both theoretical and practical insights for the efficient and cost-effective harvesting of MBC, underscoring the potential of CTS/DTE composites in enhancing the sustainability of ABS systems.

High-Performance Rotating Structure Triboelectric-Electromagnetic Hybrid Nanogenerator for Environmental Wind Energy Harvesting.

As environmental energy harvesting gains increasing importance in self-powered systems and large-scale energy demands, wind energy, as a clean, pollution-free, and renewable source, has garnered widespread attention. However, achieving efficient wind energy collection remains challenging. This study proposes a high-performance rotating structure triboelectric-electromagnetic hybrid nanogenerator designed for environmental wind energy harvesting. By optimizing the magnetic circuit design of the electromagnetic generator, the dispersed radial magnetic field is converted into a unified axial magnetic field, enabling efficient power generation with only a single annular coil, thereby simplifying the generator design and reducing manufacturing and maintenance costs. Additionally, a triboelectric nanogenerator design with soft contact friction between polycarbonate (PC) fur and fluorinated ethylene propylene (FEP) film was implemented, optimizing the spacing between the electrode and friction layers, thus enhancing output performance and device durability. Furthermore, we simulated and experimentally tested the output waveform of the designed hybrid generator structure, with the results showing a high degree of similarity, further validating the rationality of the device design and providing guidance for structural optimization. Subsequently, we achieved efficient energy storage using an energy management circuit (EMC). With the integration of the EMC, the generator successfully powered a Bluetooth temperature and humidity sensor at a wind speed of 10 m/s, achieving wireless transmission, and demonstrating its potential application in traffic signal systems and other natural environmental systems. This research provides an important reference for further exploration of novel wind energy harvesting technologies.

Research on triboelectric-piezoelectric energy harvesting technology driven by wind

Abstract In this paper, the triboelectric-piezoelectric energy harvesting technology is systematically studied. Piezoelectric materials and friction materials are combined to form integrated piezoelectric plates. A wind energy harvester based on integrated piezoelectric plates is designed and its performance is evaluated. Experimental results reveal that the maximum peak voltage for piezoelectricity and triboelectricity are 38.91 V and 12.4 V, respectively. Notably, the output voltage of the integrated piezoelectric plate is observed to increase by 31.87% compared to the original piezoelectric plate. The maximum piezoelectric peak voltage of the overall wind energy harvester is 145.23 V, and the maximum triboelectric peak voltage is 43.25 V, which can provide continuous power for small components. The integrated piezoelectric plates demonstrates a substantial enhancement in the original piezoelectric output voltage, indicating significant application potential.

High-efficiency quad-band RF energy harvesting system with improved cross-coupled differential-drive rectifier

Abstract RF energy harvesting technology has garnered significant attention from researchers in recent years. This paper presents a high-efficiency quad-band RF energy harvesting (RFEH) system. It introduces an improved cross-coupled differential-drive rectifier designed for ambient wireless powering, capable of harnessing power from four distinct ambient RF sources: FM-100, DTV-600, GSM-1800, and WiFi-2400 frequency bands. The proposed RFEH system demonstrates notable advancements, achieving a high RF to DC conversion efficiency of over 80 % within an input power range of −5 dB m to +13 dB m, with a 5 kΩ resistance load. This power output is deemed sufficient for energizing low-power micro-devices autonomously, without reliance on external power sources. Notably, the DC output voltage of the proposed RFEH system exhibits a high level of stability against variations in input power, a characteristic not adequately addressed in existing systems.

Free‐Standing, Multifunctional Thermoelectric and Acoustic Absorbing Nanocomposite Foams

AbstractThermoelectric materials are potential energy harvesting technologies that enable direct, clean conversion between thermal and electrical energy. The efficacy of thermoelectric energy conversion is influenced by the electrical conductivity, thermal conductivity, and Seebeck coefficient. Flexibility, manufacturability, and cost‐effectiveness are also important factors. Polymeric nanocomposites offer advantages in these respects. However, the development of conductive‐polymer thermoelectric materials is limited to an in‐plane architecture, which does not resemble common real‐world scenarios. Moreover, existing works have low thermoelectric properties or rely on additives for performance improvement. In this work, a free‐standing thermoelectric nanocomposite foam is fabricated via the integration of thermally activated microspheres. Due to the microstructure, a thermal conductivity as low as 0.03 W m−1 K−1 is achieved, which is lower than reported for aerogels fabricated via freeze‐drying methods. Additionally, the nanocomposite foam can reach a maximum electrical conductivity of 1.13 S cm−1, power factor of 0.12 µW m−1 K−2, and thermoelectric figure of merit of 3.0 × 10−4. The study also evaluated the compressive stiffness and demonstrated the potential for sound absorption. With the unique combination of the thermoelectric, sound absorption, and mechanical behavior, these nanocomposite foams would offer versatile solutions to address the next generation energy harvesting and acoustic absorption applications.