Renewable Energy Applications Research Articles

Novel modular multilevel matrix converter topology for efficient high-voltage AC-AC power conversion

Introduction. This paper delves into the practical application of multilevel technology, particularly focusing on the capacitor-clamped converter as a promising solution for medium-to-high voltage power conversion, with specific emphasis on direct AC-AC switching conditions. Problem. The limitations of conventional single-cell matrix converters (MC) in efficiency and performance for medium-to-high voltage power conversion applications are well-recognized. Goal. The primary objective is to investigate the performance of the 3 phase modular multilevel matrix converter (3MC) with three flying capacitors (FCs) modeling. This investigation utilizes the Venturini method for gate pulse generation, aiming to compare the performance of the 3MC with standard converter designs. Methodology. To achieve the research goal, the Venturini method is adopted for generating gate pulses for the 3MC, representing a departure from conventional approaches. Detailed simulations employing MATLAB/Simulink are conducted to comprehensively evaluate the performance of the 3MC in comparison to conventional converter designs. Results. The simulation outcomes reveal a significant reduction of 73 % in total harmonic distortion (THD) achieved by the 3MC. This reduction in THD indicates improved robustness and suitability for medium-to-high voltage power conversion systems necessitating direct AC-AC conversion. These results highlight the efficacy of the 3MC in enhancing power conversion efficiency and overall performance. Originality. This paper contributes novel insights into the practical implementation of multilevel technology, particularly within the realm of capacitor-clamped converters. Furthermore, the utilization of the Venturini method for gate pulse generation in the 3MC represents an original approach to enhancing converter performance. Practical value. The research findings present significant advancements in multilevel transformer technology, offering valuable guidance for optimizing transformer design in various industrial and renewable energy applications. These contributions serve to enhance the development of reliable and efficient power systems, addressing critical needs in the energy sector. References 54, tables 3, figures 4.

Investigation of electronic, optical and thermoelectric properties in orthorhombic perovskite SmFeO3

In this work, we have investigated the electronic, optical, and thermoelectric properties of orthorhombic perovskite SmFeO3 using density functional and Boltzmann transport theories, for renewable energy applications. The modeling of the exact electron exchange-correlation has been carried out using both Generalized Gradient Approximation (GGA) and a functional modified with Hubbard interactions. The spin-polarized calculations show that SmFeO3 adopts a G-type antiferromagnetic configuration. The studied compound's electronic band structure and density of states analysis reveal its p-type semiconductor behavior. Furthermore, the optical properties such as real ε1(ω) and imaginary ε2(ω) components of the dielectric function as well as other conventional optical parameters, were investigated. The results show that SmFeO3 is a promising material for optoelectronic applications. The calculated transport properties including the Seebeck coefficient (S), the electrical conductivity (σ/τ), the electronic thermal conductivity (k0/τ) and the electronic figure of merit (ZTe) show significant results. The studied perovskite is also a potential candidate for thermoelectric applications, due to its high Seebeck coefficient, reaching 2388 μV/K, and the large electronic figure of merit which is close to 1 at room temperature. To improve the thermoelectric performance of SmFeO3 material, we have studied the effect of both p-type and n-type doping on its thermoelectric behavior at different temperature values.

Recycling of spent heat pack towards Fe-Fe3O4@NC catalyst for 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 for direct methanol fuel cell (DMFC), 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 and 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.

Optimization, imaging and LHE analysis of magnesium oxide nanoparticles synthesized with carambola extract as natural dye sensitizer

This work explores the enhancement of dye-sensitized solar cells (DSSCs) by using magnesium oxide nanoparticles (MgO NPs) that have been green-synthesized, with carambola extract acting as a natural dye sensitizer. Green synthesis minimizes the negative effects of traditional synthesis methods on the environment by providing a sustainable and ecologically friendly way to produce MgO NPs. To increase their effectiveness in DSSC applications, the synthesized nanoparticles underwent optimization. The morphology and size distribution of MgO NPs were characterized by scanning electron microscopy (SEM), which revealed spherical forms with a consistent size distribution. The crystalline nature of the MgO NPs was verified by X-ray diffraction (XRD), which revealed distinctive peaks that correspond to the bulk MgO crystal planes. A band gap of 3.5 eV, appropriate for UV region absorption, was found using UV–visible spectroscopy. FT-IR (Fourier-transform infrared) spectroscopy revealed information about their molecular compositions. Positive electronic characteristics, such as a negative total energy change (ΔE_T) and a high electrophilicity index (ω), which indicates effective charge transfer, were found through computational analysis. The light harvesting efficiency (LHE) value of 0.00459 signifies optimal light absorption capability by the dye molecule. The outcomes show that MgO NPs that have undergone green synthesis have the potential to be efficient and stable sensitizers for DSSCs. In addition to highlighting the significance of green synthesis techniques in nanomaterial research for renewable energy applications, this work advances the development of efficient and sustainable solar energy systems.

Cattaneo-christov heat flux theory in tangent hyperbolic hybrid nanofluids with thermal radiation for renewable energy applications

The aim of current paper is to explore the dynamics of Tangent hyperbolic hybrid nanofluid flow and heat transfer over a stretchy surface, combined effect of thermal radiation and Cattaneo-Christov heat flux effects also incorporated in the energy equation. Hybrid nanofluids are advanced class of nanofluid have several engineering applications due to their enhanced thermal, electrical, and rheological properties. Here we developed a mathematical model for two-dimensional hybrid nanofluid containing particles copper (Cu) and alumina oxide (Al2O3) suspended with base fluid H2O. Variable viscosity and viscous dissipation aspect also amalgamated in the present study. After applying the dimensionless variables, the governing PDE's are converted into ODE's. The numerical computations are performed with the help of MATLAB software. The most important outcomes predefined pertinent parameters like magnetic parameter, Weissenberg number, relaxation time, thermal radiation parameter, prosperity parameter, convective parameter, Prandtl number, heat source parameter, Eckert number, on velocity and temperature profile are thoroughly examined graphically and physically. There occur increment in the temperature profile of hybrid nanofluid than regular nanofluid. Also over current outcomes shows close agreement for a particular cases.

Influence of non-metals doping on the structural, electronic, optical, and photocatalytic properties of rutile TiO2 based on density functional theory computations

This study investigates the influence of non-metal doping (C, F, N, and S) on the structural, electronic, and optical properties of rutile TiO2 using Hubbard-corrected density functional theory (DFT) within the Quantum ESPRESSO code. Rutile TiO2 is a promising material for environmental remediation and renewable energy applications. However, it has a large bandgap of 3.03 eV, which confines its use to UV light. By substituting oxygen atoms with a single dopant atom, we aim to shift the absorption edge toward the visible spectrum. Our findings reveal that doping with C, N, and S results in a redshift of the bandgap, while F doping does not exhibit this effect. The imaginary part of the dielectric function indicates shifted absorption edges for C, N, and S-doped TiO2, making them suitable for photocatalytic applications. Additionally, an increased refractive index after doping suggests the presence of excess charge carriers that affect light propagation. This work provides valuable insights for experimentalists exploring non-metal doping influences on rutile TiO2 for photocatalysis.

Ultra-low temperature heating system based on dual-source solar assisted heat pump using compound parabolic concentrator-capillary tube solar collector

The fifth-generation heating – ultra-low temperature heating benefits to reduce electricity consumption and achieve the net zero goal. The dual-source solar assisted heat pump based heating system has been demonstrated to be an attractive green heating technology for the domestic sector. However, the slower response speed of the low temperature heating to the variation of heating load in responding to the variations of weather conditions limits its thermal comfort performance. The enhancement in solar collector performance brings valuable improvements in response speed of the heating system. In the present work, a heating system based on solar assisted air source heat pump using a compound parabolic concentrator-capillary tube solar collector (CPC-CSC) is investigated with the set heating temperatures of 40, 45, 50, and 55 °C. This heating system works for both space heating and hot water under the weather conditions in London. The results suggest that using a concentrated solar collector improves the response speed of the heating system at low set heating temperatures. For such a heating system, the ultra-low heating temperature increases the application of renewable energy and passive heating (by 6.4%). Compared with the dual-source indirect expansion solar assisted heat pump using flat plate collector, the heating system using CPC-CSC can reduce TEWI by 4.6% with a slightly longer (1.9%) payback period. As the set heating temperature decreases from 55 to 40 °C, the seasonal and yearly system seasonal performance factors significantly increase by 17.1% and 20.5%, respectively.

Repurposing Industrial and Agricultural Wastes as Sustainable Alternatives in Photovoltaic Cells and Dye Degradation

AbstractCombustion of coal at thermal power plants generates enormous amounts of coal fly ash (CFA). Proper disposal of CFA is an important issue today because environmental problems are considered a burning issue worldwide. On the other hand, groundnut shells (GNS), regarded as agricultural waste in general, litter landfills everywhere and create soil degradation. Since both CFA and GNS contain abundant silica, this work focuses on extracting amorphous silica from these materials through a total dissolution–precipitation process. The silica was extracted from it and used to prepare titanium oxide (TiO₂) hybrids. The GNSS were extracted from GNS, and the CFAS was extracted from the CFA. The methods used were based on sol–gel. These hybrids were further tested for the performance of their solar cells in dissolving dyes. The overall results of the obtained physical properties of CFAS and GNSS are similar to those of conventional silica. More importantly, TiO₂/GNSS and TiO₂/CFAS hybrids showed enhanced photocatalytic efficiency compared to the pure TiO₂. Therefore, it is evidence of repurposing CFA and GNS, which have high potential for use as sustainable applications in renewable energy and environmental remediation.

Power Converter Topologies for Heat Pumps Powered by Renewable Energy Sources: A Literature Review

Heat pumps (HPs) have become pivotal for heating and cooling applications, serving as sustainable energy solutions. Coupled with renewable energy sources (RES) to run the compressor, which is the major energy-consuming component, they contribute to eco-conscious practices. Notably, their adaptability to be supplied by either alternating (AC) or direct (DC) currents, facilitated through converters, makes them more flexible for versatile renewable energy (RE) applications. This paper presents a comprehensive review of converter topologies employed in various HP applications. The review begins by exploring previous applied photovoltaic (PV)-HP projects, focusing on the gaps in the literature concerning the employed converter topologies. Additionally, the review extends to include a broader examination of the converter topologies that could be employed on the source and load sides of a system powered by a mix of renewable energy sources, such as photovoltaics (PV), wind turbines (WTs), and energy storage systems (ESS), and analyzes their strengths and weaknesses. Special emphasis is given to understanding the various topologies of the power electronics converters in the context of HP applications. Finally, the paper concludes with a summary of the literature gaps, challenges, and directions for future research.

Quantifying Solar Radiation Over Northern India and Validating with Cropwat for Agricultural and Renewable Energy Applications

Precise computation of global solar energy is crucial for many fields of investigation such as renewable energy, meteorology, and agriculture especially crop water requirement and irrigation requirement. This paper presents the quantification of solar radiation using weather data during the years from 2020-21. The results obtained were validated with the solar radiation estimated with the help of CROPWAT during the year. Statistical and visual approaches were adopted to validate the quantified results. Analysis revealed the high degree of similarity between simulated and CROPWAT determined daily solar radiation during the year 2020-21 over the study area. Very high values of Willmot index of agreement (1.0), Nash-Sutcliffe efficiency (0.999), and Pearson correlation coefficient (0.998), and low values of mean absolute error (0.138), mean bias error (-0.024), and root mean square error (0.182) between them was observed during the year 2020-21 in the area. The minimum solar radiation reaching over the region were observed to be around 5.71 MJ/m2/day during winter season (January) with a normal value of 13.50 MJ/m2/day, while the maximum value of 24.5 MJ/m2/day was observed during the summer season (June) with a normal value of 24.13 MJ/m2/day over the region. The use of these data for further study is recommended as it is worthful quantification over the region.

Efficiency-aware machine-learning driven design of solar harvester for renewable energy application

Although MIM structures have been studied for solar thermal applications for decades, the multilayer MI-MIM structure is the subject of this study's investigation for batter absorption. In order to identify an effective solar absorber, two configurations Gold-MgF2-Gold (GMGSA) and Gold-MgF2-Gold-MgF2-Gold (GMGMGSA) are examined in this work. By using machine learning approaches, this research was able to get an MSE of 2.8091 × 10−5 and an R2 value of 0.998836. The optical response and parameter optimization analysis have been examined in this work in the wavelength range of 0.4 μm–1.6 μm. When exposed to AM 1.5 spectrum radiation, the GMGMGSA absorbs 93.10 % of the radiation, compared to 88.30 % for the single-layer GMGSA. Furthermore, both structures show steady absorption that is independent of polarization up to a 70° incidence angle. The aforementioned discoveries render the structure a plausible contender for solar thermal uses, including battery-integrated photovoltaic (BIPV), commercial solar power (CSP), and solar water heating. This might lead to a future where energy is more sustainably produced.

Damage evolution simulation and lifetime prediction for composite blades under continuous droplet impacts

Offshore wind power generation is a promising technology in renewable energy applications due to its high reserves of wind energy in sea areas. To improve the energy transformation efficiency, the blade length of the offshore wind turbines has become larger and larger, and it has made rain erosion be one of the most frequent failures during the turbine operation. As the natural rainfall is stochastic in spatial and time domains, it is difficult to depict the damage evolution process caused by rain impact exactly. Therefore, regular and continuous droplet impact simulation and experiments present an alternative methodology for this issue. With the composite structure of the blade and deformability of the liquid droplet in consideration, a fluid solid interaction model will be established to investigate the impact response and subsequent damage evolution. In which, the Smooth Particle Hydrodynamics (SPH) model is utilized to depict the constitutive relationship within the droplet, and Finite Element Method (FEM) is used to construct the Representative Volume Element (RVE) model of the blade leading edge. The impact process is simulated first to obtain the impact pressure distribution at the contact center and velocity field in the droplet. Furthermore, the stress wave propagation in the blade multilayer structure can be analyzed. Owing to the multiaxial fatigue feature of the continuous droplet impact, the continuum damage mechanics is integrated with the fatigue criterion and the Jump-in-Cycle procedure is used to simulate the high-cycle fatigue process. The damage factor distribution on the blade coating surface and its influence on mechanical properties are analyzed. Thereafter, the droplet impact fatigue life can be accumulated based on Miner’s linear rules. The theoretical achievements are validated by experimental data provided by Rain Erosion Testing (RET), which shows a good agreement between each other. As a result, V-N curves and D-N curves, i.e. quantitative relationship between droplet falling conditions and impact fatigue life, are established. The achievements in this study can provide an effective tool for rain erosion mechanism analysis and life prediction in industrial applications.

Applying Circular Thermoeconomics for Sustainable Metal Recovery in PCB Recycling

The momentum of the Fourth Industrial Revolution is driving increased demand for certain specific metals. These include copper, silver, gold, and platinum group metals (PGMs), which have important applications in renewable energies, green hydrogen, and electronic products. However, the continuous extraction of these metals is leading to a rapid decline in their ore grades and, consequently, increasing the environmental impact of extraction. Hence, obtaining metals from secondary sources, such as waste electrical and electronic equipment (WEEE), has become imperative for both environmental sustainability and ensuring their availability. To evaluate the sustainability of the process, this paper proposes using an exergy approach, which enables appropriate allocation among co-products, as well as the assessment of exergy losses and the use of non-renewable resources. As a case study, this paper analyzes the recycling process of waste printed circuit boards (PCBs) by disaggregating the exergy cost into renewable and non-renewable sources, employing different exergy-based cost allocation methods for the mentioned metals. It further considers the complete life cycle of metals using the Circular Thermoeconomics methodology. The results show that, when considering the entire life cycle, between 47% and 53% of the non-renewable exergy is destroyed during recycling. Therefore, delaying recycling as much as possible would be the most desirable option for minimizing the use of non-renewable resources.

Numerical simulation of a hybrid energy system proposed for low carbon data center

Low-carbon energy application for both large grid and distributed energy consumers is an urgent problem to be solved. Data centers (DC) are the typical distributed large-size energy consumers, and the application of renewable energy and energy storage is a promising solution for data center decarbonization. This paper developed a complete hybrid energy system (HES) simulation process for data center applications. The photovoltaic (PV) cell, hydrogen electrolysis, hydrogen storage, proton exchange membrane fuel cell (PEMFC), lithium battery (BAT), grid, and data center load are considered in the HES. A one-dimensional two-phase flow PEMFC model is developed. The detailed mass transfer process inside the PEMFC cell is modeled. The PEMFC model-solving algorithm is developed and integrated into the HES simulation program. The energy management system (EMS) based on a logical flow chart energy management strategy is integrated by editable subfunction. The HES simulation program is coded and implemented based on the MATLAB-SIMULINK environment. The yearly HES performance simulations are conducted and analyzed for a 200 kW data center in Xi’an with different HES parameters and an appropriate HES parameter arrangement is provided. The main contribution of this work is the development of an editable HES simulation program that is extensible for data center applications.

Structural and Optical Characterization of Cu2Se0.8S0.2 Thin Films Deposited by Thermal Evaporation

Abstract A simple cost thermal evaporation deposition technique was used to prepare of Cu2SeS thin films on the substrates made of glass at RT with thickness ( 500 + − 20 ) nm . Structural, and optical properties of these films were investigated. The films were structurally characterized using X-ray diffraction XRD analyses, the film samples were morphologically characterized using atomic force microscopy (AFM), and optical UV-Vis spectroscopy was also to characterize the samples. The films have been treated at deferent temperatures (403, 453 &503) K for 1 hour, X-ray diffraction (XRD-with wavelength 1.54 A) study the structure properties of this films suggest a cubic structure and have prominent (111) orientation. AFM analysis, it is evident that Cu2SeS film is polycrystalline in nature, and that crystallite size and average grain size for films after annealing were increasing. The optical absorption coefficient (α) of the film was evaluated using absorbance spectra in the wavelength range (400-1100) nm. The direct band gap of about 2.2 eV, decrease by increasing annealing temperature, The structure and the optical characteristics of these films may have practical applications in renewable energy.

Experimental and comparative analysis between nitrile rubber foam insulated and vacuum insulated fiber reinforced plastic tank used in a low temperature sensible heat storage system for building space cooling applications

AbstractThermal energy storage devices are gaining importance and momentum in the building space cooling and renewable energy applications. Retaining the stored energy for long hours through proper insulation is crucial in achieving economic benefits. In the present research, a novel composite material (FRP) is introduced for the development of cool storage tank along with two different methods of insulation (nitrile rubber foam insulation and vacuum insulation) to assess the performance of cool energy retention. The results show that the effect of vacuum insulation is lower compared with nitrile rubber foam insulation. This is due to the low specific heat capacity of the FRP material compared with air that increases the surface temperature of the tank than the ambient air during the day time in the case of vacuum insulation. Hence the study concludes that the additional layer of insulation material with high specific heat capacity than the ambient air to be added on the surface to avoid the overheating of the wall surface. The results are useful in designing the insulation for thermal storage tanks and managing the heat loss.

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

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.