Harvesting System Research Articles

Modeling and Analysis of MEMS Electrostatic Energy Harvesting System

Modeling and Analysis of MEMS Electrostatic Energy Harvesting System

METHOD FIRST APPROXIMATION STABILITY ANALYSIS OF ELECTRICAL CONTROL SYSTEMS

This article is devoted to the research and analysis of automated control systems and control of electrical equipment of technological processes of agricultural production. The first approximation method is used for evaluation the stability of the operation of electric drive control systems. Methods for assessing the stability zone of electric drive control systems, determining critical gain coefficients, and optimizing the parameters of electrical circuits included systems, in order to increase the efficiency and reliability of production chains are proposed. To solve the problem of controlling the electric drives of automated systems for harvesting and sorting agricultural crops, the method was tested, a critical gain value of 3.2 was obtained, which allows us to talk about optimizing such systems in terms of speed and load.

Integrating Micro-Hydro and Solar PV in Rainwater Harvesting: A Hybrid Generation Approach

As the scarcity of water worsens and the frequency of severe weather increases, the efficient harvesting of rainwater becomes more critical. Despite its potential to conserve water and mitigate flooding, the integration of rainwater harvesting with solar PV and micro-hydro technologies remains underutilized in renewable energy production. A significant barrier to widespread adoption is the challenge of accurately quantifying energy generation and optimizing management practices. This project aims to address these issues by proposing a method to develop a rainwater harvesting system that integrates solar PV and micro-hydro technologies. The primary objective is to evaluate the practical performance of this hybrid system in driving applications such as irrigation and sanitation. The findings demonstrate that the integrated system outperforms conventional methods, suggesting its effectiveness in rainwater utilization as a renewable energy resource.

Modified extended Rauch–Tung–Striebel smoother method for the dynamic external excitation identification of piezoelectric vibration energy harvesting systems

A vibration energy harvester can collect vibration energy from the environment to supply low-power devices, such as wireless sensor nodes. Reducing the size and power consumption of these devices is a challenging problem. A dual-function device, which includes energy harvesting and vibration measurement, may solve this problem. Therefore, studying inversion methods for identifying the external excitation of a harvester is meaningful. In this study, a modified inversion method that combines an extended Rauch–Tung–Striebel smoother (ERTSS) with the particle swarm optimization (PSO) algorithm, i.e., the ERTSS-PSO method, is proposed to identify the time domain signal of external excitation through the voltage response of a piezoelectric vibration energy harvester. A modified ERTSS approach with sliding windows is developed. The sliding windows are partially overlapped to eliminate identification errors between the two contiguous windows. Near real-time identification is achieved for the small sliding window. PSO is utilized to estimate state noise covariance and measurement noise covariance, improving identification accuracy compared with the L-curve approach. Under this proposed framework, prior knowledge regarding the statistical data of unknown external excitations is unnecessary, enabling a more comprehensive range of applications. To assess the performance of the proposed ERTSS-PSO method, numerical simulations, including two piezoelectric vibration energy harvesting systems with third-order and fifth-order nonlinear stiffness, are conducted to verify the effectiveness of the proposed method under harmonic, multifrequency, and random excitations. The method proposed in this study is also validated by a circular laminated piezoelectric plate harvester under harmonic and random excitations in an experiment. Results from the experimental studies demonstrate that the proposed method improves identification accuracy by at least 9% compared with the extended Kalman filter, at least 7% compared with the augmented Kalman filter (AKF) with Rauch–Tung–Striebel smoother (ARTSS), and at least 40% compared with AKF under random excitation. In addition, the proposed method is unaffected by initial conditions, and it is more stable and accurate than AKF and ARTSS. The proposed method lays the theoretical foundation for identifying the external excitation of a harvester. It is also a possible solution for the miniaturization and compactness of wireless monitoring devices.

Sistem Panen Kelapa Sawit di Sekunyir Estate, Kalimantan Tengah

Palm oil (Elaeis gueenensis Jacq) is an important vegetable oil in Indonesia. Palm oil productivity is influenced by various factors including harvest management. This research had specific objectives to be achieved, namely studying and understanding the management of palm oil harvesting, and analyzing the factors that influence the effectiveness and efficiency of palm oil harvesting. The research was conducted at Sekunyir estate, Central Kalimantan from February to May 2014. Data collection was obtained by direct and indirect methods. Field observations were conducted by following 8 harvesters on the Division of Labour (DOL) system and 4 harvest teams on the 1 Cutter and 2 Carrier (C1R2) system. This research concluded that changing the harvest system from the DOL system to the C1R2 system had a good impact on crop management and the productivity of the harvest team. The C1R2 system had a yield of 5-7% higher than the DOL system in obtaining ripe fruit and had a smaller number of rotten fruits which was around 2.6% compared to the DOL system which reached 8%. Keywords: harvest efficiency, C1R2 system, DOL system, harvesting technique, labor

Impact of Lattice Strain on the Electronic and Thermoelectric Properties of CoAs3 Skutterudite Material

Using density functional theory (DFT) combined with semi‐classical Boltzmann transport theory, the electronic and thermoelectric properties of binary skutterudite CoAs3 material are investigated up to 30 GPa. Elastic properties calculations confirm the mechanical stability at 0 GPa and under varying hydrostatic pressures, with ductility influenced by pressure. To ensure dynamical stability, the phonon dispersion frequencies are computed at both 0 and 30 GPa. Electronic band structure calculations, using the GGA + TB‐mBJ approximation, indicate that CoAs3 initially exhibits a direct band gap at its equilibrium lattice constant, which shifts to become indirect under increasing pressure. To assess the impact of pressure on the thermoelectric properties of CoAs3, the Seebeck coefficient, thermal conductivities, and figure of merit (ZT) are calculated at pressures of 5, 10, 20, and 30 GPa for various temperatures (300, 600, 900, and 1200 K). These computations provide valuable insights into how varying pressures influence the material's thermoelectric performance. The optimal thermoelectric properties in CoAs3 material are achieved at 5 GPa and 1200 K for n‐doping (20 GPa and 600 K for p‐doping), with an ideal doping concentration of 1.5 × 1021 cm−3 (5.5 × 1018 cm−3). Under these conditions, the material reaches a high figure of merit (ZT) value of 0.52 for n‐doping and 0.49 for p‐doping. These findings underscore CoAs3 as a promising candidate for applications in energy harvesting and optoelectronic systems, showcasing its robust thermoelectric performance under precise pressure and temperature conditions.

Stable RbCsFAPbI3 perovskite solar cell: numerical modelling and optimisation using SCAPS-1D

The studies concerning solar cell technology has consistently been captivating and inspiring, largely because of its environmentally friendly and sustainable characteristics. The outstanding electronic, optical, mechanical, and electrical characteristics of perovskite materials make them crucial for the development of the photovoltaic industry. In order to model the mixed cation Rb0.05Cs0.1FA0.85PbI3 perovskite solar cells, the SCAPS-1D tool was used. The main feature of RbCsFAPbI3 perovskite is its remarkable stability, and wide bandgap. Rubidium (Rb) and cesium (Cs) cations improve the optoelectronic characteristics of the material, resulting in less non-radiative recombination and improved charge transfer. In this work, the effects of different hole transport layers (CuSCN, CuSbS2,Cu2O) and back metal contacts (Ag, Fe, C-Cu, Au, Ni, Pt) on solar cell performance were investigated. The maximum efficiency of the solar cell has been achieved by studying various parameters like temperature, series resistance, shunt resistance, defect density, and absorber layer thickness. With FF = 84.12%, Jsc = 24.52 mA cm−2, Voc = 1.19 V, and the configuration of FTO/TiO2/RbCsFAPbI3/Cu2O/Au, the optimised device obtains a PCE of 24.64%. The impressive enhancements in performance parameters observed in the structure of the device make it highly suitable for applications in solar energy harvesting systems.

A self-powered and self-sensing hybrid energy harvester for freight trains

Freight trains, being crucial for economic development, often face challenges due to the lack of electrical infrastructure. In this study, a self-powered and self-sensing hybrid energy harvester system (SS-HEH) is proposed, it consists of an electromagnetic generator (EMG), a piezoelectric energy harvester (PEH), and an energy input module. The proposed EMG utilizes a rolling magnet to intersect the square coil, thereby better adapting to the operational conditions of freight trains and producing higher electrical energy output. Additionally, the PEH converts bogie vibration signals into electrical signals to detect bogie operations. The EMG acts on the PEH, inducing bending and generating electrical signals. Conversely, the PEH acts on the EMG to maintain it horizontally, enhancing its ability to absorb the vibration energy of the bogie and forming a bistable system. Furthermore, at a speed of 40 km/h, the EMG voltage with PEH increased by 43.75 % compared to the scenario without PEH. The electrical performance of the SS-HEH was assessed through shake table experiments, yielding an RMS voltage of 11.5 V and output power of 74.1 mW. In addition, combined with deep learning, SS-HEH has an accuracy of 97.41 % in detecting the operating status of bogie.

The charcoal footprint of greater Accra on the Afram Plains: Urban energy consumption and forest degradation in Ghana

Rapid urbanisation in sub-Saharan Africa is leading to increased energy consumption and a growing reliance on charcoal as a fuel source, with significant environmental implications. This study examines the impact of charcoal consumption in Greater Accra, Ghana, on the Afram Plains ecosystem. Employing a mixed-methods approach, including geographical analysis, quantitative data collection, and sustainability assessment, we evaluate the charcoal footprint of Greater Accra. Our findings reveal that charcoal remains the dominant cooking fuel in Greater Accra despite increased access to electricity, resulting in an estimated loss of 354,479 trees annually in the Afram Plains. This demand creates an ecological deficit of 18,850 hectares/yr, significantly exceeding the ecosystem's regenerative capacity. We observe complex dynamics between urban energy needs and rural resource sustainability, highlighting socio-economic factors driving persistent charcoal use. The study proposes a conceptual framework integrating urban demand, rural supply, ecological impact, and natural regeneration. Our research contributes to urban sustainability literature, offering insights for policymakers to develop more sustainable energy strategies, including quota systems for harvesting, promoting alternative cooking fuels, community-based forest management, and improved charcoal production technologies. This case study provides valuable lessons for other rapidly urbanizing regions facing similar sustainability challenges in sub-Saharan Africa.

Thermoresponsive nanofiber yarns for water harvesting enhanced by harp system

The escalating global water crisis necessitates innovative approaches to developing sustainable water resources. Fog water collectors with variable surface wettability offer controlled fog harvesting in water-scarce regions. This study develops thermoresponsive fog collecting materials by electrospinning poly(N-isopropylacrylamide)-polyvinylidene fluoride (PNIPAm-PVDF) into yarns that are transformed into harp-like structures for enhanced water harvesting rate. Both meshes and harps using electrospun membranes exhibit the remarkable ability to transition between hydrophilic and hydrophobic wetting states at temperatures below the lower critical solution temperature (LCST). Hydrophilic and hydrophobic surfaces play distinct roles in fog water collection. Hydrophilic surfaces have a high affinity for water and enables droplet capture. Hydrophobic surfaces help the removal of aggregated water droplet and fog water collection. The highest water collection rate obtained with the electrospun PNIPAm-PVDF harp was 1415 ± 7.0 mg·cm−2 h−1. The water harvesting system based on the electrospun PNIPAm-PVDF harps exhibits a 485 % increase in water collection compared to the standard meshes made from the same material, emphasizing their potential for significantly improving the overall rate in fog water harvesting applications.

Complex Multi-nonlinearity for piezoelectric energy harvesting systems based on an accurate higher-order perturbation method

A theoretical model of a complex nonlinear coupling energy harvester under hybrid excitations is established with analytical and numerical solutions. Different orders of the method of multiple scales are derived to approximate and analyze the equation of motion for the electromechanical coupling system, thus obtaining higher-order approximate analytical solutions for its operating status and output performance indicators. The significant effects of external excitation, linear and nonlinear damping coefficients, as well as impedance on the transverse displacement, voltage, and power of higher-order and lower-order methods are analyzed. The results show that higher-order solution methodology are more sensitive to parameter excitation. For a large damping, the higher-order analysis has more excellent performance in capturing energy. The higher order method shows more pronounced nonlinear softening phenomenon and it is more suitable for low frequency environments. The higher order methods improves solution accuracy of piezoelectric energy harvesting systems. Consequently, it is easier to derive the nonlinear performance of the harvesting systems, and thus improves the average output power.

Robust Multi-Band DNG metamaterial absorber for GPS (L1), ISM, and 5G application with Enhanced polarization and angle stability

This research introduces a triple-band metamaterial absorber characterized by insensitivity to both polarization and incident angles. The structure includes square ring resonators on the upper side and a continuous metal ground on the lower side, separated by an FR4 substrate. At the lowest operating frequency, the unit cell’s thickness, and length measure 0.0128λ and 0.156λ, respectively. Under normal incidence, the proposed absorber demonstrates three clear absorption peaks at 1.56, 2.43, and 3.36 GHz, achieving absorption rates of 98 %, 99 %, and 97 %, respectively. The absorption response exhibits variation with incident angles up to 70° for both TM and TE polarizations due to its high-level symmetry. This configuration attains negative permittivity and permeability suitable for operational frequencies in the L-band and S-band. The study examines the electric field, impedance, and surface current to provide additional evidence for the absorption analysis. A validated RLC circuit equivalent to the proposed structure has been confirmed using Advanced Design System (ADS). The results indicate a slight deviation, especially at frequencies beyond the resonance frequencies. The structure underwent fabrication and testing in an anechoic chamber, revealing a strong correlation between the simulated and measured results. The suggested absorber holds promise for ISM applications, radar systems, sensing technologies, and energy harvesting systems.

Performance Analysis of Low Frequency Piezoelectric Energy Harvesting Systems with Multiple Nonlinear Factors and Bidirectional Excitations

Performance Analysis of Low Frequency Piezoelectric Energy Harvesting Systems with Multiple Nonlinear Factors and Bidirectional Excitations

Energy harvesting from transverse galloping using a two-degree-of-freedom flow energy harvester

Abstract A two degree-of-freedom (2-DOF) galloping piezoelectric energy harvesting system where both oscillators are excited by the incoming flow is studied in this paper. A coupled lumped-parameter model is developed to simulate the electro-fluid-structural coupling behaviour assuming a quasi-steady aerodynamic flow field. The differential equations governing the dynamics of the lumped system are converted into nonlinear algebraic equations employing the harmonic balance method (HBM) and then solved using Newton’s method. The approximate analytical solutions are compared to the solutions obtained by numerical integration, and the results agree, both qualitatively and quantitatively. The solutions were subsequently used to investigate the effects of the bluff body dimension, mechanical, electrical, aerodynamic, and electromechanical parameters on the performance of the harvester and to illustrate how to optimise some of these parameters to reduce the cut-in wind speed and maximise the power output of the energy harvester. It will be shown that the energy harvesting performance could be significantly improved by introducing piezoelectric transducers on both oscillators and including both masses in the incoming flow. A comparative study between the proposed 2-DOF flow energy harvesting system, a single-degree-of-freedom (SDOF) galloping piezoelectric energy harvester (GPEH), and other configurations of 2-DOF GPEH shows that the present 2-DOF GPEH generates the largest power peak.

Solar driven atmospheric water harvesting system with integration of desiccant wheel and desiccant bed: An experimental investigation

Solar-driven atmospheric water harvesting (SDAWH) presents a promising solution to address water scarcity issues, particularly in arid and semi-arid regions where conventional water sources are limited. This paper presents a new SDAWH system, integrated with a desiccant wheel and desiccant bed. The desiccant bed adsorbs water vapour during night and desorbs in a day time. Whereas the desiccant wheel performs adsorption and desorption process simultaneously in day time. Therefore, the combination of these offers the potential to enhance water yield and energy efficiency compared to conventional sorption-based SDAWH systems in semi-arid climate. Further, an evacuated tube solar air heater for regeneration and an air-to-air heat exchanger for condensation of water vapour has been integrated. The desiccant bed releases large amount of water vapour in regeneration air but its desorption gradually decreases with time. On the other hand, the desiccant wheel releases a lesser quantity of water vapour into the regeneration air, but its desorption capacity remains almost constant. The system’s performance has been evaluated in a semi-arid climate. As the system is working in closed cycle, the dew point temperature of regeneration air obtained at the outlet of the desiccant wheel is 39.4 °C, which increases to 42.4 °C at the outlet of the desiccant bed. The total yield of water in a day is 7.6 L, with an energy efficiency of 9 %.

Enhancing Urban Climate Resistance Through the Application of Selected Strategies and Technologies

Adapting cities for climate resilience is crucial as climate change increases the frequency and severity of extreme weather events. This study outlines a comprehensive set of resilience strategies aimed at enhancing urban resilience across four key domains: water, food, shelter, and energy. These strategies, applicable to both new and existing neighborhoods, range from simple, short-term measures to complex, long-term initiatives. A three-pronged evaluation framework, consisting of three platforms, is introduced to assess these strategies where criteria are initially selected based on their impact on strategy adoption and implementation. This framework employs hypothetical scores and weights that can be adjusted for specific urban contexts through detailed studies. Key outcomes of the evaluation conducted in the first platform include a systematic method to rank strategies based on six criteria: cost, infrastructure impact, scalability, regulatory and zoning challenges, community acceptance, and maintenance needs. For example, community gardens and rainwater harvesting systems are highly scalable and accepted, whereas green roofs require more investment and maintenance. The second and third platform of the framework facilitate the identification of strategies that enhance resilience across each of the resilience domains, as well as across several domains. The results highlight the top-performing strategies under different weighted scenarios. Strategies like green roofs strategy scores high in domains like water management, due to its capacity to absorb and manage stormwater, and energy, by providing natural insulation that reduces heating and cooling demands. Additionally, green roofs contribute to food production when utilized for urban agriculture and enhance shelter by improving building durability and increasing biodiversity This data-driven framework supports the strategic prioritization of resilience strategies, enhancing urban planning and investment decisions globally. Its modularity ensures adaptability to diverse urban settings and climatic issues.

3D printed Ti3C2@Polymer based artificial forest for autonomous water harvesting system

The escalating scarcity of freshwater resources presents significant challenges to global sustainability, demanding innovative solutions by integrating cutting-edge materials and technologies. Here we introduce an autonomous artificial forest (3D AF) for continuous freshwater acquisition. This system features a three-dimensional (3D) architecture incorporating a carbon nanofiber (CNF) network and MXene@polypyrrole (Ti3C2@PPy), enhancing surface area, light absorption, heat distribution, and surface wettability to improve solar vapor generation and fog collection efficiency. The autonomous operation is facilitated by an integrated photothermal actuator that adjusts to the day and night conditions. During daylight, the 3D AF tilts downward to maximize solar exposure for water evaporation, while at night, it self-adjusts to optimize fog particle collection. Notably, our device demonstrates the ability to harvest over 5.5 L m−2 of freshwater daily outdoors. This study showcases the potential of integrating advanced materials and technologies to address pressing global freshwater challenges, paving the way for future innovations in water harvesting.

Integrated Impact of Olive Mill Wastes and Semi-Circular Bunds on Soil Properties and Rainwater Harvesting Efficiency in Egypt’s Northwestern Coastal Zone

ABSTRACT The productivity of olive in the northwestern coastal zone of Egypt is significantly constrained by drought and low organic matter in the soil. This study addresses these challenges by exploring the synergistic effects of olive mill wastes (OMW) application and micro-catchment water harvesting techniques on soil properties, runoff, moisture storage, and rainwater harvesting efficiency. Field experiments were conducted over two winter seasons, employing different micro-catchment structures (semi-circular and triangular bunds) and OMW applications. The results revealed that the integration of semi-circular bunds with OMW application (T4) substantially increased rainwater harvesting efficiency by 67.7% and 46.4% in the first and second seasons, respectively. Additionally, T4 and T5 exhibited reduced runoff by 47.8% and 41.3% in the first season and 49.4% and 38.9% in the second season, respectively. T4 significantly enhanced soil organic matter, soil macronutrients (N, P, and K), and micronutrients (Fe, Mn, Zn, and Cu) compared to the control (T1). The study highlights the effectiveness of T4 in improving soil moisture, reducing soil erosion, and enhancing soil fertility. This integrated approach involving OMW application within a semi-circular bund as a water harvesting system proves to be a promising strategy for sustainable olive cultivation in arid conditions.

Factors Affecting Rainwater Harvesting Practices: In Case of Assosa Town, Upper Blue Nile Basin, Northwestern Ethiopia

In many parts of the world, conventional water supplies do not exist, are unreliable or prohibitively expensive. Many actual or potential water shortages can be alleviated if the practice of rainwater harvesting becomes widespread. A study was conducted to evaluate the factors affecting rainwater harvesting practices in Assosa city. The reason for starting the research is that the municipality of Assosa suffers from a severe water shortage, especially at the end of the dry season. The study involved 99 randomly selected respondents and purposively selected respondents using a semi-structured questionnaire. Data were collected using a combination of data collection methods including survey interviews, key informant interviews, and direct observation. The data was analyzed using descriptive statistics such as frequency tables to draw conclusions and recommendations. The results showed that lack of funding played a key role in the adoption of rainwater harvesting and, furthermore, lack of information and poor technology contributed to the failure to adopt rainwater harvesting for domestic use. It was determined that roofing materials were not a problem in the area, but storage areas and gutters hindered rainwater collection. We therefore concluded that the implementation of rainwater harvesting systems in Assosa town was hampered by the lack of resources required for the installation of rainwater harvesting systems. In addition, inadequate accesses to information, particularly for women, and lack of knowledge about the maintenance of rainwater harvesting technologies have contributed to the lack of widespread adoption of rainwater harvesting. We recommend making a conscious effort to subsidize rainwater harvesting in this area. The study also recommends strengthening municipal capacities in the area of rainwater harvesting technology, which is expected to be important for improving rainwater harvesting technology.

Energy Harvesting system with battery-supercapacitor hybrid storage for highly maintenance-free remote sensing stations

Energy Harvesting system with battery-supercapacitor hybrid storage for highly maintenance-free remote sensing stations