Renewable Energy Applications Research Articles

High Step-Up Three-Port DC–DC Converter With Few Limitations in Performance Suitable for Stand-Alone Renewable Energy Applications

High Step-Up Three-Port DC–DC Converter With Few Limitations in Performance Suitable for Stand-Alone Renewable Energy Applications

Recycling of spent heat pack towards Fe-Fe3O4@NC based cathode for electrocatalytic ORR in direct methanol fuel cells and Al-air batteries

The effective repurposing of waste materials is crucial for sustainable development. The widespread use of disposable iron-based chemical warmers (IBCW) generates substantial solid waste annually. In this study, IBCWs were repurposed as raw materials to synthesize different electrocatalyst composites comprising metallic and oxide forms of iron embedded in nitrogen-doped carbon (NC). The composites were evaluated as oxygen reduction reaction (ORR) catalysts. The optimized Fe-Fe3O4@NC demonstrated enhanced ORR kinetics, with an onset potential of 0.92 V and a half-wave potential of 0.86 V vs. RHE. As an air cathode, Fe-Fe3O4@NC achieved a power density of 33.3 mW cm−2 at 88 mA cm−2, demonstrating its practical applicability. Additionally, a quasi solid-state aluminium-air battery (SAAB) was assembled using this catalyst as the air cathode with a PVA-KOH gel electrolyte as the separator. The quasi SAAB exhibited an open circuit voltage (OCV) of 1.46 V, a power density of 40 mW cm-2, and good rate capability compared to Pt/C. The combined effect of metallic and oxide iron with nitrogen doping enhances the overall catalytic activity. This study demonstrates that IBCWs can be effectively transformed into valuable catalysts for renewable energy applications, enabling clean and sustainable utilization of waste materials.

Research Progress of Battery Thermal Management Systems with Minichannels

With the developing technology, energy storage systems, especially lithium-ion batteries (LiBs), play a critical role in electric vehicles and renewable energy applications. However, the performance and life of batteries are significantly affected by their operating temperatures. In this context, battery thermal management systems (BTMS) are of vital importance to ensure temperature control of batteries and to create a safe operating environment. BTMSs are divided into main two groups active and passive which require and does not require extra energy consumption, respectively. In this review, the basic principles, design criteria and application areas of battery thermal management systems are examined. First of all, the components of BTMS, passive and active cooling methods, heat dissipation and temperature monitoring techniques are detailed. In addition, the effects of different BTMS approaches on efficiency and performance are compared. The analysis of existing studies in the literature reveals the positive contributions of BTMS on battery life, charge-discharge efficiency and safety. In addition, future research areas and development opportunities are also highlighted. In conclusion, an effective thermal management system is a critical factor in the development of battery technology and has great potential in terms of sustainability of energy systems.

A Novel NR-DA-Based ANN for SHEPWM in Cascaded Multilevel Inverters for Renewable Energy Applications

Harmonics is the major power quality problem caused by nonlinear devices, leading to malfunction or operational halt of the system. Low-order harmonics increase vibration and heat generation in motors. Therefore, controlling harmonics in the output waveform is the prime target for industrial applications to avoid economic loss. Selective harmonic elimination pulse width modulation (SHEPWM) is one of the techniques used for eliminating or minimizing selected harmonics in the output voltage waveform. This paper utilizes the Newton-Raphson method and Dragonfly Algorithms to calculate optimum switching angles for a Cascaded H-bridge Multilevel inverter (CHBMLI). The algorithms use non-linear equations to calculate the Switching Angles of MLI. The Dragonfly algorithm requires several iterations to reach an optimum solution. For complex problems, this algorithm becomes computationally expensive and time-consuming. A lookup table addresses the limitation by offline training an Artificial Neural Network (ANN) to generate the optimum switching angle for a given modulation index. Neural Fitting Tool in MATLAB software is used to train the ANN model. The simulation is performed using MATLAB SIMULINK software for both 5-level and 7-level CHBMLI configuration. The Dragonfly algorithm-based ANN achieves THD 8.84% when the modulation index (M) equals 0.8 for a 7-level inverter and THD 14.91% for a 5-level inverter and effectively minimizes third and fifth-order harmonics.

Optimizing Algal Oil Extraction and Transesterification Parameters through RSM, PCA, and MRA for Sustainable Biodiesel Production

This study presents a comprehensive optimization of algal oil extraction and transesterification for sustainable biodiesel production. Freshwater Spirogyra algae underwent Soxhlet extraction using n-hexane. response surface methodology (RSM), principal component analysis (PCA), and multivariate regression analysis (MRA) were employed to investigate the effects of biomass–solvent ratio (BSR), algae particle size (APS), and extraction-contact time (E-CT) on algal oil yield (AOY). The extracted oil was then converted to biodiesel via transesterification, and the impacts of the methanol–oil ratio (MOR) and transesterification-contact time (T-CT) on biodiesel conversion efficiency (BCE) were analyzed. Results demonstrate that optimal BSR, APS, and E-CT for maximal AOY are 1:7, 400 µm, and 3–4 h, respectively. For transesterification, a MOR of 12:1 and a T-CT of 4 h yielded the highest BCE. Predictive models exhibited exceptional accuracy, with R2 values of 0.916 and 0.950 for AOY and BCE, respectively. The produced biodiesel complied with ASTM D6751 and EN 14214, showcasing its potential for renewable energy applications.

A novel artificial neural network based selection harmonic reduction technique for single source fed high gain switched capacitor coupled multilevel inverter for renewable energy applications

Multilevel inverters (MLIs) are commonly used in renewable energy systems for their high-quality output, low total harmonic distortion (THD), and reduced component count. This study presents a high-gain, single-source MLI designed for renewable applications like solar or wind power. It features a novel topology with twice the voltage-boosting factor, utilizing a single DC source. The inverter achieves thirteen voltage levels using just 10 power switches and three switched capacitors. The voltage gain is achieved without the need for bulky DC-DC converters or transformers. This is accomplished by configuring the switched capacitors in series and parallel arrangements to attain the desired voltage boost. Additionally, the self-balancing capacitors eliminate the need for extra sensors. Both symmetric and asymmetric variants of the extensible configuration are investigated. The suggested design lowers the total standing voltage (TSV) while achieving high gain. A selective harmonic removal technique using artificial neural networks (ANN) reduces THD by up to 6.07 %. An extensive review of recent literature reveals significant advancements and applications of ANNs in this field. The proposed system's benefits, such as gain factor, total standing voltage (TSV), and minimized device count, are assessed. Comparative analysis reveals that the proposed topology employs fewer components and features a more simplified design. Additionally, the inverter achieves an efficiency of 96.9 %. The design is validated through an experimental prototype after being confirmed with MATLAB/SIMULINK.© YEAR The Authors. Published by Elsevier Ltd.Peer-review under responsibility of the scientific committee of the Name of the Conference, Conference Organizer Name, Year or Edition of Conference.

Computational study of Rubidium-Rb based cubic Rb2TlCoF6 double perovskite material for photocatalytic water degradation applications: A DFT investigations

The fascinating characteristics, such as straightforward and stable crystal structure, and double perovskites are currently popular materials for applications in renewable energy. In our study, we applied CASTEP and DFT, called density functional theory, to theoretically investigate the mechanical, optical, and thermoelectric characteristics of cubic Rb2TlCoF6. Calculations of the compound Rb2TlCoF6's structural, electrical, optical, mechanical, and thermodynamic properties are made using the GGA-PBE exchange correlational functional and the Fm3m with space group no.225 vol and compound lattice constant are 9.08 Å and 748.613 Å3, respectively. For Rb2TlCoF6, the measured energy band gaps are 1.45 eV. The mechanical and elastic constants are calculated to confirm the ductile properties of Rb2TlCoF6. The brittle characteristics have been verified using Passion and Pugh's ratios, which are 1.67 and 0.25, according to elastic constants. Vickers compound hardness Hv and anisotropy factor “A” are 4.19 and 0.77, respectively. The compounds' optical characteristics reveal significant conductivity and absorption. The compound exhibits high-efficiency photocatalytic activity based on its optical characteristics. Based on mechanical stability, such as Debye temperature, melting temperature, minimum thermal conductivity, average sound velocity, free energy, and other variables, the thermodynamic and structural stabilities are calculated. These materials controlled electrical and other properties make them potentially useful in photocatalytic applications. According to the outcomes, Rb2TlCoF6 is appropriate for photocatalytic water-splitting applications and water deterioration.

A Detailed Analysis and Gain Derivation of Reconfigurable Voltage Rectifier-Based LLC Converter

In this paper, a complete analysis of an LLC resonant converter with a customized rectifier structure is presented. The converter is intended for wide, low-input, high-output voltage DC bus applications. The performance of the converter is assessed using comprehensive time-domain and fundamental harmonic approximation (FHA), which demonstrates its capacity to operate across an ample range of voltages by precisely adjusting the rectifier structure. The converter’s capability is illustrated by deriving and discussing detailed mode operation, steady-state analysis, and DC gain equations. In order to verify the theoretical analysis, a prototype with a power output of 250 watts is constructed and subjected to testing. The results of the testing demonstrate that the converter is both feasible and effective. The experimental findings illustrate its capacity to manage vast voltage ranges while upholding high efficiency. In addition, the converter utilizes a frequency switching modulation (FSM) to connect with a photovoltaic (PV) panel and control the high output voltage. This demonstrates its adaptability in renewable energy applications. The validation is in accordance with theoretical predictions, demonstrating the converter’s high-efficiency performance and versatility.

A DFT Approach to Insight on the Structural, Optoelectronic and Thermoelectric Properties of Cubic Perovskites YXO3 (X = Ga, In) for Renewable Energy Applications

A DFT Approach to Insight on the Structural, Optoelectronic and Thermoelectric Properties of Cubic Perovskites YXO3 (X = Ga, In) for Renewable Energy Applications

Eminent Red Sea water hydrogen generation via a Pb(ii)-iodide/poly(1H-pyrrole) nanocomposite photocathode

Abstract The development of a photocathode based on a Pb(ii)-iodide/poly(1H-pyrrole) porous spherical (PbI2/P1HP PS) nanocomposite has been successfully achieved in the efficient production of H2 gas from Red Sea water. The distinguishable spherical and porous shapes of these nanocomposites are characterized by a minimum surface measuring approximately 25 nm. This structural configuration, coupled with the nanocomposite’s substantial light absorbance, results in a modest bandgap of 2.4 eV. This turns the nanocomposite into a highly promising candidate for renewable energy applications, particularly for H2 gas generation from natural sources like Red Sea water. The economic viability of the PbI2/P1HP PS nanocomposite, relying on a glass substrate, mass production, and straightforward fabrication techniques, adds to its promising profile for H2 gas evolution. The photocathode exhibits significant potential for H2 gas production, with a notable current density (J ph) value of 1.0 mA·cm−2 in a three-electrode cell configuration. The IPCE reaches 3.1%, reflecting the successful evolution of 24 µmol·h−1 10 cm2 of the photocathode. Importantly, the use of natural Red Sea water as an electrolyte underscores a key feature for H2 gas production: utilizing freely available natural resources. This aspect holds considerable promise for industrial applications, emphasizing the environmentally sustainable nature of the photocathode.

3D printing of phase change material-based Pickering emulsion gel for solar-thermal-electric conversion

The rapid global increase in the consumption of fossil energy had led to urgent environmental issues, thereby prompting vigorous efforts towards the development and application of renewable energy. The effective encapsulation of phase change materials (PCMs) is crucial and indispensable for achieving high-performance solar-thermal energy harvesting and storage. However, challenges persist in the manufacturing of PCMs encapsulations with customizable and intricate structures to meet diverse scenarios. Herein, a PCMs Pickering emulsion gel ink, based on lignocellulosic nanofibers (LCNFs)/graphene oxide (GO) nanosheets stabilized paraffin, has been prepared to fabricate customized PCMs using 3D printing techniques for solar-thermal-electric conversion applications. The micro-nano matrix consisting of LCNFs and GO nanosheets provides a stable oil/water (O/W) interface, limits movements and deformability of paraffin microsphere, thereby increasing the viscosity and stiffness of the PCMs Pickering emulsion gel ink to ensure its excellent rheological property. Moreover, the LCNFs enhance printability and shape fidelity of the ink as interfacial stabilizer and viscosity modifier, which facilitates the manufacture of various 3D geometries. As a result, the designed concave PCMs solar harvester not only exhibits exceptional solar-to-thermal conversion efficiency, but also effectively mitigates heat loss and enables efficient heat storage for electricity generation. Our work demonstrates a new way toward utilization of LCNFs as PCMs emulsion stabilizers and encapsulants in PCMs and the fabrication customized PCMs architectures for solar-thermal-electric conversion applications using 3D printing techniques.

Hedgehog Zinc Oxide-Graphene Quantum Dot Heterostructures as Photocatalysts for Visible-Light-Driven Water Splitting.

The development of efficient photocatalysts for sustainable hydrogen production via water splitting is vital for advancing renewable energy technologies. In this study, we present the synthesis and characterization of a novel visible-light-active photocatalyst comprising hedgehog-shaped zinc oxide (ZnO) nanostructures coupled with graphene quantum dots (GQDs). Optical properties assessed by UV-visible and photoluminescence (PL) spectroscopy revealed that the ZnO/GQDs heterostructure possessed a reduced band gap (2.86 eV) compared with pristine ZnO (3.10 eV), resulting in improved light absorption and charge separation. Electrochemical analyses indicated a significantly higher photocurrent response and lower charge transfer resistance for the ZnO/GQDs heterostructure compared with the pristine ZnO nanostructure. Photocatalytic tests demonstrated that the ZnO/GQDs heterostructure achieved over 3-fold higher hydrogen (H2) production rates, with an apparent quantum yield (AQY) of 1.51% at 440 nm, and maintained stable activity over prolonged reaction periods. These results highlight the enhanced photocatalytic efficiency and stability of the ZnO/GQDs heterostructure, underscoring its potential as a high-performance photocatalyst for sustainable hydrogen generation. The synergistic effects between ZnO nanostructures and GQDs offer valuable insights into the design of advanced photocatalytic materials for renewable energy applications.

Photocatalytic CO2 Reduction to Solar Fuels by a Chemically Stable Bimetallic Porphyrin-Based Framework.

Porphyrin-based photocatalysts have emerged as promising candidates for facilitating carbon dioxide (CO2) reduction due to their exceptional light-harvesting properties. However, their performance is hindered by complex synthesis procedures, limited structural stability, inadequate CO2 activation capabilities, and a lack of comprehensive structure-property relationships. This study investigates the performance of a porphyrin-based bimetallic framework, [Cu(TPP)Cu2Mo3O11] (TPP = tetrapyridylporphyrin), termed MoCu-1 for photocatalytic CO2 reduction. In addition to its straightforward one-pot synthesis method, the framework shows remarkable chemical stability, particularly notable in alkaline reaction conditions, making it a compelling option for sustainable catalytic applications. By harnessing the superior photoabsorption properties of the porphyrin linker and the abundance of catalytic sites provided by the bimetallic structure, this framework exhibits the potential for enhancing CO2 reduction efficiency. MoCu-1 demonstrates excellent activity in converting CO2 into CO, achieving a maximum yield of 3.21 mmol g-1 with a selectivity of ∼93%. We unravel the intricate interplay of structural features and catalytic activity through systematic characterization techniques and an in situ diffuse reflectance Fourier transform study, which provided insights into the mechanism governing CO2 conversion and was supported by density functional theory calculations. This work contributes to advancing our understanding of photocatalytic processes and offers guidance for designing robust materials for CO2 utilization in renewable energy applications.

Use of Triboelectric Nanogenerators in Advanced Hybrid Renewable Energy Systems for High Efficiency in Sustainable Energy Production: A Review

Renewable energy is the best choice for clean and sustainable energy development. A single renewable energy system reveals an intermittent disadvantage during the energy production process due to the effects of weather, season, day/night, and working environment. A generally hybrid renewable energy system (HRES) is an energy production scheme that is built based on a combination of two or more single renewable energy sources (such as solar energy, wind power, hydropower, thermal energy, and ocean energy) to produce electrical energy for energy consumption, energy storage, or a power transmission line. HRESs feature the outstanding characteristics of enhancing energy conversion efficiency and reducing fluctuations during the energy production process. Triboelectric nanogenerator (TENG) technology transduces wasted mechanical energies into electrical energy. The TENG can harvest renewable energy sources (such as wind, water flow, and ocean energy) into electricity with a sustainable working ability that can be integrated into an HRES for high power efficiency in sustainable renewable energy production. This article reviews the recent techniques and methods using HRESs and triboelectric nanogenerators (TENGs) in advanced hybrid renewable energy systems for improvements in the efficiency of harvesting energy, sustainable energy production, and practical applications. The paper mentions the benefits, challenges, and specific solutions related to the development and utilization of HRESs. The results show that the TENG is a highly potential power source for harvesting energy, renewable energy integration, application, and sustainable energy development. The results are a useful reference source for developing HRES models for practical applications and robust development in the near future.

Investigation on the hydrogen storage properties, electronic, elastic, and thermodynamic of Zintl Phase Hydrides XGaSiH (X = sr, ca, ba)

This study presents a comprehensive investigation of the electronic, mechanical, and thermodynamic properties of Zintl phase hydrides XGaSiH (X = Sr, Ca, Ba) using Density Functional Theory (DFT) and the FP-LAPW method within the WIEN2k package. Our analysis covers the structural stability, electronic properties, and hydrogen interaction mechanisms in these compounds. The hydrides exhibit narrow band gaps, with values ranging from 0.1 to 0.5 eV using GGA and LDA functionals, and 0.6–1.0 eV with mBJ-GGA and mBJ-LDA. The hydrogen storage capacities are determined to be 0.34 wt %, 0.47 wt %, and 0.40 wt % for SrGaSiH, CaGaSiH, and BaGaSiH, respectively, highlighting their potential for energy storage applications. Thermodynamic properties, evaluated through the quasi-harmonic Debye model, provide insights into the Grüneisen parameter, heat capacity, and thermal expansion coefficient over a range of pressures (0–50 GPa) and temperatures (up to 1000 K). Elastic constants reveal that these compounds are mechanically stable, with a notable anisotropy in the {100} plane and varying degrees of compressibility among the different hydrides. Our study further highlights the slightly ordered hexagonal Ga and Si layers, which contribute to the enhanced hydrogen storage capabilities of these materials. The compounds demonstrate high structural stability, facilitating effective hydrogen retention and release at practical temperatures, making them promising candidates for hydrogen storage applications. Additionally, the analysis of electronic band structures and density of states suggests significant conductivity potential, with band gaps ranging from 0.1 to 1.0 eV, depending on the computational method used. The unique combination of structural, electronic, thermodynamic, and mechanical properties in XGaSiH compounds positions them as valuable materials for renewable energy applications. These findings lay the groundwork for future research focused on optimizing these materials through structural modifications or doping to enhance performance metrics such as hydrogen storage capacity and electrical conductivity.

Experimental Study on the Combined Heat Storage and Supply of Air/Water-Source Heat Pumps

As the application of renewable energy becomes increasingly extensive, heat pump technology with renewable energy as the heat source is achieving good results. Air-source heat pumps and water-source heat pumps can be widely used in cold areas. In this work, an integrated combined storage and supply system of an air-source heat pump and a water-source heat pump was studied, and the heating characteristics of the system at the beginning, middle, and end of the heating period were examined. It was found that, when the outdoor temperature of the system was very low, the efficiency of the combined storage and supply system reached the highest value of 2.57 when the source-side water tank was kept at 30 °C, and the performance of the combined storage and supply system was better than that of the air-source heat pump and the water-source heat pump in cold regions. Meanwhile, the independent storage of the air-source heat pump and the combined storage and supply system can be used for heating at the beginning and end of the heating period.

A New Cascaded Multilevel Inverter for Modular Structure and Reduced Passive Components

In high-power applications, achieving adequate power quality in power converter design is accomplished by utilizing multilevel inverters instead of using two-level and three-level inverters. The device generates a sinusoidal output voltage, which results in reduced total harmonic distortion and lower voltage stress on the switches and leads to lower electromagnetic interference, making it suitable for use in renewable energy applications. However, to illustrate the advantages mentioned above, a significant number of switching devices and DC sources are necessary while raising the voltage levels. This article proposes an asymmetrical voltage generation method, which operates in a ratio of 1:5 and generates 25 levels using 11 power switches. The topology is modular in structure, and each module has a lower component count, which significantly reduces the overall cost. The proposed topology is capable of generating negative output voltage levels without the use of an H-bridge configuration, where only three switches are used to generate any voltage levels. The functionality of the developed module is amended by fixing different voltage values in DC sources. This article also presents a comprehensive examination of the circuit and the functioning of various voltage levels. The advantages of the proposed inverter have been demonstrated by comparative research with the currently existing MLI topologies. Ultimately, both the simulation and experimental findings validated the practical capabilities.

A new positive output DC–DC buck–boost converter based on modified boost and ZETA converters

A new DC–DC buck–boost converter with a wide conversion ratio is presented in this paper. The proposed buck–boost converter consists of a combination of modified boost converter and ZETA converter, which has the advantages of both converters such as continuous input/output current and positive polarity of the output voltage. The combination of these two converters achieves semi-quadratic voltage gain and makes the proposed converter suitable for industrial and renewable energy applications. With a voltage gain higher than that of the ZETA converter and modified boost converter, the proposed converter also reduces input current stress due to its continuity. Two operating states are available for this converter in continuous conduction mode. This converter has two switches that operate simultaneously and can be easily controlled. The converter's output voltage ripple and output capacitor current stress are reduced as a result of continuous output current. Computational analysis and the introduced structure efficiency considering the influence of parasitic elements are presented in this paper. The small signal modelling and closed-loop control, as well as simulation and experimental results are also presented. This converter has also been compared with other similar and recently presented topologies. Finally, a 40–60 W, 20–76 V for boost mode and 10 V for buck mode prototype was implemented to verify the accuracy of the computational analysis.

Enhancing renewable energy utilization and energy management strategies for new energy yachts

Hydrogen energy, due to its clean and efficient nature, has shown great potential during the current transition period in the shipbuilding industry. However, the application of hydrogen energy in ship energy systems is influenced by variations in operational load and the integration of new energy sources during actual navigation. To address these issues, this paper focuses on optimizing and scheduling the operation of ships under various navigation conditions, considering the distributed nature of hydrogen energy. System simulations were conducted to model the photovoltaic (PV), proton exchange membrane fuel cells (PEMFCs), lithium batteries (LIBs), electrolytic cells (ECs), and energy storage modules of yacht energy systems. Component boundaries and objective functions were set, and two cases (excess photovoltaic state and constant power state) were designed to optimize and regulate the energy balance of hydrogen-powered yachts, enhancing their comprehensive utilization of renewable energy. By comparing the changes in ship energy under the two cases, it was concluded that case 1 ensures the maximum utilization of renewable energy. When photovoltaic power generation is insufficient, the PEMFC and LIB in the system provide the required power to achieve a supply-demand balance. Moreover, when PV power generation is sufficient, hydrogen energy is used to store renewable energy. The optimization method designed in this study can, to some extent, maximize the application of renewable energy in new energy yachts, ensuring the efficiency of the comprehensive energy system of new energy yachts, reducing emissions, and improving the sustainability and economic efficiency of the ships.

A High Step-Up Hybrid Y-Source-Quasi-Z Source DC–DC Converter for Renewable Energy Applications

A High Step-Up Hybrid Y-Source-Quasi-Z Source DC–DC Converter for Renewable Energy Applications