Journal of Solar Energy Research Updates
Journal of Solar Energy Research Updates is a peer reviewed scientific journal encompassing experimental, theoretical and applied research results with respect to field of solar energy. It provides a forum for architects, engineers and researchers involved in the design, construction and utilization of photovoltaics and solar energy systems. Solar Energy Research Updates publishes original technical papers, reviews, technical brief notes, and discussions on all aspects of solar derived energy for generation of mechanical and electrical power, including both active and passive solar applications.
Numerical Simulation and Performance Analysis of a Water-Based Photovoltaic/Thermal (PVT) Collector Using Simulink Environment
The hybrid photovoltaic-thermal (PVT) collector is an innovative technology that exploits solar energy to simultaneously generate electricity and heat. It thus optimizes the use of the surface exposed to sunlight by maximizing total energy production, offering a higher overall efficiency compared to standard thermal collectors or separately installed photovoltaic panels. In this research, a “sheet and tube” type water-based PVT collector was studied numerically. The main objective is to develop and analyze a hybrid PVT collector to optimize its overall efficiency. A mathematical model was developed for each component of the PVT collector (glass cover, PV module, absorber plate, tube, fluid, and insulation). Subsequently, the Hottel-Whillier thermal model was implemented and simulated in the Simulink/Matlab environment to study the collector’s performance. Furthermore, the effects of mass flow rate, number of glazings, inlet fluid temperature, and the heat transfer coefficient between the absorber plate and the PV module, among other operating parameters, were analyzed to identify their influence on electrical and thermal performance. A comparative analysis between PV and PVT collectors was conducted, and annual thermal and electrical energy productions were evaluated to assess the overall performance of each system.
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Regional Strategies for PV-Based Sustainable Energy in GCC and Europe
This study analyzes the feasibility of the production of solar power as a sustainable solution to the climate and energy crisis, focusing on two areas in particular: the Gulf Cooperation Council countries and Europe. Focused attention goes to emerging economies in analyzing how solar power can aid in reducing carbon dioxide emissions and attaining sustainable development. Comparative analysis is performed for the GCC region and Europe on the basis of unique solar system design ability and the performance of photovoltaic (PV) systems, taking into account realistic environmental and working parameters. In this comparative design research, mathematical equations were applied to determine the number of required solar panels to achieve determined energy efficiency in both regions. A novel mathematical modeling approach was designed and presented as new equations to achieve a correct estimate of the quantity of PV panels required from the energy requirement and a parameter called the Power Generation Factor (PGF). The practical design approach employed in the present work synchronizes the technical aspects of electrical system design with broader sustainable development goals, particularly for developing nations. By creating new mathematical equations for estimating how many PV panels would be necessary based on desired energy yields and incorporating the PGF, the study underscores the photovoltaic efficiency and panel requirement disparity between the GCC and European regions. These disparities owe to differences in solar energy generation and electricity generation factors between regions. The suggested approach is scalable and can be applied to other areas with comparable energy requirements, making it a tough and adaptable planning instrument for sustainable energy infrastructure deployment.
Photovoltaic Thermal Power Supply Based on Smart Grid Functioning Solar Electric System Network
Integrated Smart Grid systems are developed to coordinate the production and consumption of electricity from a grid-connected solar power plant, providing power to a heat pump and hot water using hybrid solar collectors. The upper section of a two-section storage tank supplies hot water, while the lower section is a low-grade energy source for the heat pump. The integrated dynamic subsystem of the solar power system includes the following components: the grid, photovoltaic solar panels, hybrid solar collectors, a grid-connected inverter, a heat pump, a two-section storage tank, and a frequency converter. The power factor and local water temperature of the grid-connected solar power system are predicted by measuring the voltage of the hybrid solar collectors at the grid-connected inverter input, the voltage at the frequency converter output, and the current frequency. Advanced solutions for varying the power of the heat pump compressor motor and the circulation pump motor are implemented in accordance with changes in the thermal output of the storage tanks connected to the hybrid solar collectors. The power of the heat pump compressor motor and the circulating pump motor is regulated based on the specified voltage ratio at the grid-tie inverter input from the hybrid solar collectors and at the frequency converter output. The functional assessment of the solar power system power factor change when connecting the heat pump is in the range of 58–98%, when connecting the hot water supply, in the range of 63.74–98%, and the local water temperature in the range of 35–55°C. When the grid-tie inverter input voltage changes from 200 V to 600 V, the power transmitted to the grid increases in the range of 0.33 to 1, the power factor by 40%. Determining the final functional information allows for early decisions to be made about changing the operating mode of the heat pump compressor motor and the circulating motor to prevent peak loads on the power grid and maintain voltage in the distributed system.
Enhancing Nighttime Power Generation: A Bionic Flower-Inspired Thermoelectric System with Photothermal Absorption and Radiative Cooling
The combination of solar energy and radiative cooling through thermoelectric generators (TEGs) offers a promising approach for sustainable power generation. However, current thermoelectric systems that integrate solar energy and radiative cooling still face the challenge of insufficient nighttime power generation capacity. This study proposes a thermoelectric power generation system featuring a heat storage structure inspired by bionic flowers, which utilizes residual heat stored during the daytime to supply heat to the hot end of TEGs at night, thereby increasing the temperature difference at night. A numerical model was developed, and the temperature field and phase change characteristics within the heat storage structure were investigated through finite element simulation. The thermoelectric system with a heat storage structure maintains a higher nighttime voltage than the one without it. After 12 AM, the system without a heat storage structure can only sustain an output voltage of approximately 18 mV. In contrast, the system with a heat storage structure can achieve a voltage output of 42.57 mV. Even four hours later, it retained a 6.64 mV advantage. The results demonstrate that the heat storage structure significantly enhances the power generation performance at night. This research provides a potential solution to effectively mitigate the issue of insufficient nighttime power generation capacity in thermoelectric power generation systems.
Impact of Solar Peak Energy and Weather Classification on BiLSTM-Based Solar Irradiance Forecasting in Equatorial Regions
Accurate solar irradiance forecasting is critical for managing solar energy systems in equatorial regions, where high solar potential is coupled with significant variability. This study investigates the influence of solar peak energy and weather classification features on a Bidirectional Long Short-Term Memory (BiLSTM) model for multi-step Global Horizontal Irradiance (GHI) prediction. The research method involved four phases: data preprocessing (including cyclical time encoding, lag features, and solar peak extraction), weather classification (pseudo-labelling refined by decision trees), BiLSTM-based forecasting with Optuna hyperparameter tuning, and model evaluation using standard error metrics. Three configurations were compared: (A) solar peak + weather classification, (B) weather classification only, and (C) core meteorological and temporal features without additional inputs. The workflow incorporated cyclical time encoding, pseudo-labelling with decision tree refinement, lag feature construction, and Optuna-based hyperparameter tuning. Model performance was assessed using MAE, RMSE, MAPE, R², and MASE. Scenario A achieved the lowest MAPE (28.74%), whereas Scenario C yielded the smallest MAE (103.59 W/m²) and MASE (0.786). Scenario B performed worst with a MAPE of 29.85% and MAE of 105.64 W/m², highlighting the limited standalone value of weather classification. Across all scenarios, RMSE values remained within 148–150 W/m² and R² around 0.68, reflecting minimal differences in variance explanation. These findings suggest that simpler models can perform as well as or even outperform more complex configurations, offering efficiency benefits for operational forecasting. The practical implication of these results is that reliable irradiance forecasts can be achieved with simpler BiLSTM configurations, reducing computational cost and supporting real-time energy management, PV system sizing, and grid stability in equatorial regions. Future work should incorporate satellite imagery and real-time cloud tracking to further enhance prediction accuracy.
Stability Enhancement in High-Penetration Wind Power Grid Integration During Fault Conditions Using a Combined MBPSS and FACTS Device Approach
This study investigates how a combination of Multi-Band Power System Stabilizers (MBPSS) and Flexible AC Transmission System (FACTS) devices might improve stability in power networks with significant wind energy penetration under fault conditions. Maintaining system stability becomes increasingly important as wind power integration rises, especially when there are disruptions that could cause electromechanical oscillations. The study uses MBPSS to model a wind turbine powered by a Doubly-Fed Induction Generator (DFIG) and assesses the performance of several FACTS devices, including Unified Power Flow Controllers (UPFC), Static Synchronous Series Compensators (SSSC), and Static Synchronous Compensators (STATCOM). According to simulation results, combining these technologies reduces oscillations significantly—for example, damping times decreased from 8 s (without controllers) to 3 s (with MBPSS and UPFC), and frequency deviations were maintained within ±0.5 Hz. These results demonstrate that the UPFC and MBPSS combination is the most effective in stabilizing the grid when wind energy levels are high.
Sustainable Energy Solutions for Himachal Pradesh: A Comparative Study of Solar Panel Technologies
The pursuit of sustainable energy solutions is critical in regions like Himachal Pradesh, India, where environmental preservation and energy access must go hand in hand. This study presents a comprehensive comparative analysis of two solar panel technologies—fixed tilted and two-axis rotating rooftop systems—under the state's on-grid rooftop solar scheme supported by central and state subsidies. Using detailed simulations in PVsyst, the research evaluates the systems’ energy efficiency, economic feasibility, environmental implications, and policy alignment. Results show that while two-axis rotating panels offer moderately higher energy yield (6.23 kWh/day vs. 4.78 kWh/day), fixed tilted panels are economically more viable, exhibiting a shorter payback period (1.8 years vs. 2.3 years) and lower installation and maintenance costs. These findings endorse fixed tilted panels as a more cost-effective and sustainable solution for residential solar adoption in the region.
Structures and Electronic Properties of Different ZnIn2S4/CuInS2 Interface: A First-Principles Study
This paper aims to explore the electronic and photoelectric properties of two-dimensional type I (straddle) heterojunctions by theoretical calculation, and to provide theoretical support for the design of novel optoelectronic devices. Several ZnIn2S4/CuInS2 two-dimensional type I heterojunctions with different terminations have been systematically investigated by density functional theory (DFT) combined with tight binding approximation. The results show that only two of these structures are stable. In these two stable structures, different chemical bonds and electron transfer directions are formed when different atoms are exposed at the interface. The calculation results of band structures show that both of these structures are two-dimensional type I heterojunctions. The calculation results of effective mass show that they have efficient carrier separation and transport characteristics. These properties indicate that these two heterostructures can be used in high-performance light-emitting devices and photoelectric sensors. This study provides a theoretical basis for the optimal design of new two-dimensional optoelectronic devices.
Retrospect on the Preparation and Application of Perovskite Materials
In recent years, the diversity of new organic-inorganic hybrid perovskite materials has received extensive attention, for tremendous outstanding properties including large optical absorption coefficients, high carrier transport mobilities, long-range charge-carrier diffusions, low exciton binding energies, adjustable bandgaps, narrow-band bright photoluminescence as well as the compatibility of simple processing techniques. Because of these excellent properties, perovskite materials are widely used in solar cells, light-emitting devices, photodetectors, photocatalysis, etc. Here we reviewed the fundamental structure and properties of perovskite materials, and summarize the diverse preparation methods of perovskites along with the key factors in nucleation and growth control to prepare high-quality bulk crystals or films with less defects and stabilized performances against the external corrosive environments. The applications of perovskite materials accompanied with the relative bulk or interface ameliorations are discussed, and finally the prospects of such materials are expected. Overall, this review demonstrates the prevailing preparation mechanisms, challenges for high-quality perovskite materials and their vital importance in corresponding applications.
Retrofitting Sunspaces in Qinghai-Tibet Plateau Vernacular Dwellings: A Mini Review of Solar Gain Enhancement Strategies and Cultural Preservation Challenges
In the context of climate change and the depletion of traditional energy sources, it is significant to explore passive building technologies that are suitable for specific climatic and geographical conditions. This paper reviews strategies for retrofitting sunspaces in vernacular dwellings on the Qinghai-Tibet Plateau, focusing on enhancing solar gain and addressing cultural preservation challenges. The unique solar utilization characteristics and architectural forms are discussed, highlighting the need for tailored retrofit technologies. The paper analyzes the technological typology of sunspaces, including sun passageways, sunrooms, and sun courts, and evaluates their performance in terms of temperature rise, economic viability, user acceptance, and cultural adaptability. Implementation barriers, such as technical, social, and economical constraints, are identified, and emerging solutions are proposed to overcome these challenges. The study aims to provide insights for future retrofit projects that balance thermal performance improvement with cultural integrity preservation in high-altitude region.
Using Point of Common Coupling (PCC) for Power Shaving in Grid Connected Hybridized Network
A network that connects all components together is referred to as a grid. A study has been conducted over hybrid system which is a self-sustainable grid. The hybrid system is connected with the grid at Point of Common Coupling (PCC). The aim of this paper is to focus on the behavior of different intermittent energy sources, which are complementary to each other or not. For this purpose, research papers related to different intermittent energy sources are considered, and the behavior of renewable sources in different regions are discussed. Integration of solar, wind and battery sources to main grid, and a suitable control system for the PCC is presented that provides uninterrupted power flow from the hybrid system to load and the main power grid. The current and voltage regulator on PCC are optimized by Particle swarm optimization (PSO) algorithm. The hybrid system in this paper contains multiple power generator sources that include photovoltaic cells (PV), wind turbine and battery. Negative impact on main power grid by changing power through PCC are also examined.
Particle swarm optimization (PSO) algorithm
Design and Testing of Transmissive Fresnel Concentration and Thermoelectric Power Generation System
In this paper, a concentrating photovoltaic and temperature difference combined power generation device is designed. The device is guided by the problem of low power generation efficiency of solar cells at high temperature, and transfers the heat of photovoltaic cells to thermoelectric cells to achieve secondary power generation. The research takes the cold end of the thermoelectric battery as the entry point, and studies its influence on the device by controlling the flow rate and temperature of the cooling liquid in the water-cooled radiator. The results show that when the flow rate is 0.5L/min ~ 2.5L/min, the photovoltaic current increases linearly and then increases nonlinearly, while the photovoltaic voltage decreases linearly and then increases nonlinearly. When the water temperature increases from 15°C to 27°C, the photovoltaic current, photovoltaic voltage and thermoelectric voltage decrease with the increase of water temperature, while the thermoelectric current increases with the increase of water temperature. Therefore, selecting the appropriate flow rate and water temperature can further improve the power generation efficiency and performance of the system.
Recent Initiatives on Fossil Fuel Transition towards Renewable Energy for Combating Climate Change and a Net-Zero Energy Future
This study presents the recent trends in the transition from fossil fuels towards renewable energy for combating climate change and achieving a net-zero energy target by 2030 as per United Nations Sustainable Development Goal-7 (Energy for All). However, the Net Zero target is difficult to achieve unless effective energy conservation and energy efficiency policies, regulations, and financial investment, are not initiated along with the major energy transition to renewable energy. Therefore, the study's objective is to present the current status of initiatives by different countries including India to address this problem as per the recommendations of various Conference of Parties including COP-29. The case study of India shows that enhanced energy efficiency, energy conservation, effective solar energy policies, and regulations for high energy-consuming sectors like industry, agriculture, buildings, domestic and awareness among society are important for achieving realistic targets. The Chhattisgarh State study identifies the high energy-consuming sectors, leading to a 2.7 million kWh reduction in energy consumption in the past two decades through various initiatives. These measures are leading India towards an efficient Net-Zero energy transition in a realistic way. The study results are of importance for follow-up action in developing and least-developed countries worldwide.
The Research Progress on Photocatalytic Materials for Pollutant Degradation: A Review
Photocatalytic technology, as a clean, green, and sustainable method for pollutant degradation, has significant scientific research value and practical application significance in the field of water pollution control. Currently, the focus of photocatalysis research is on developing efficient, stable, and low-cost photocatalysts. Researchers are enhancing the light absorption capacity, electron-hole separation efficiency, and degradation rate of photocatalysts by designing novel photocatalysts, such as S-type heterojunctions, Z-scheme structures, precious metal doping, and non-metal regulation. The mechanistic study of the photocatalytic process, especially the separation, migration, and transfer mechanisms of photogenerated carriers, provides theoretical support for the optimization design of photocatalysts. At present, there are various types of catalysts for photocatalytic degradation of pollutants, including metal oxide catalysts (e.g., TiO2, ZnO), precious metal catalysts (e.g., platinum, gold, silver), carbon-based catalysts (e.g., graphene, carbon nanotubes), and composite catalysts (e.g., metal oxide-carbon-based composite catalysts).Each type of catalyst has shown performance in improving photocatalytic efficiency and expanding the light absorption range, but also faces challenges such as limited light absorption range, poor catalyst stability, and high cost. Composite catalysts significantly improve photocatalytic efficiency through synergistic effects, especially excelling in the degradation of high-concentration pollutants. Future research will focus on further optimizing the performance of catalysts, particularly expanding the light absorption range, improving electron-hole separation efficiency, and enhancing catalyst stability. The design of composite catalysts remains the focus of research, especially the exploration of synergistic effects between different materials. At the same time, issues such as the long-term stability, recyclability, and selectivity of catalysts need to be addressed to support their large-scale application.
Black Coloured Glazes with Tetragonal CuCr2O4 Ceramic Pigment as Selective Solar Absorbers for Integral Ceramic Solar Collectors
An efficient and low-cost Selective Solar Absorber for integral ceramic solar collectors, based in glazes pigmented with t-CuCr2O4 and Sb modified t-CuCr2O4 pigments, are characterised and evaluated. The basic kinds of industrial glazes (soda lime glass, double firing glaze 1050 ºC and both single firing glazes of 1080 ºC and porcelain glaze of 1190 ºC) have been checked and characterised by CIEL*a*b* colour, UV-Vis-NIR diffuse reflectance spectra, bandgap measurements, SEM-EDS analysis and solar absorbance spectra. The characteristics of the black powders (L*a*b* and diffuse reflectance spectra with a deviation from the carbon black ΔE*=20.3 and 22.3 respectively) are improved in 0.5 wt% addition of pigments in soda lime glass (ΔE*=6.1 and 9.9 respectively) and in 5 wt% glazed in porcelain glaze 1190 °C (ΔE*=12.0 and 18.4 respectively) which can be considered as low-cost selective solar absorbers (SSA) for integral solar absorber collectors.
The Energy Consumption Comparison of Temperature Difference-based Defrosting Exit Method and Time-based Defrosting Exit Method with Various Static Pressure Differences
The time-based defrosting exit method(TDEM) has been widely used in cold storage, but the issue of energy consumption has been heavily criticized. In this paper, a temperature difference-based defrosting exit method(TDDEM) is proposed to compare with TDEM. Firstly, a parameter acquisition system of cold storage is constructed, and the experimental setup is conducted to determine the experimental parameters. Subsequentially, the range of defrosting static pressure difference is determined based on pre-frosting experiment, and the defrosting experiment of TDEM and TDDEM are carried out at five various static pressure difference conditions, 16Pa, 14Pa, 12Pa, 10Pa and 8Pa, respectively. The results show that the temperature fluctuations per defrosting events of TDEM are more severe compared to TDDEM, with with average increases of 102.2%, 91.6%, 59.3%, and 46.5%, respectively. Energy consumptions of TDDEM are markedly lower than TDEM, with reductions of 21.4%, 15.7%, 14.09% and 14.59%, respectively. Whether TDEM or TDDEM, the lowest energy consumption is occurred at 10Pa, and highest is 8Pa.
Biogas Heat Pump Power Supply Based on Smart Grid Functioning Solar Electric System Network
A comprehensive integrated solar power plant system has been developed to support the operation of a biogas plant based on a heat pump, for which fermented wort is a low-potential energy source. The change in the power factor of the solar power system connected to the grid and the temperature of the coolant entering the heat exchanger built into the methane tank are predicted. Promising solutions include changing the power of the heat pump compressor to maintain biogas production, unloading fermented wort and loading fresh material while maintaining the power factor of the grid solar system and changing the level of electricity transmission to the grid. The voltage at the input of the hybrid inverter, the voltage at the output of the frequency converter to assess their ratio and the voltage frequency are constantly measured. When changing the voltage at the input of the hybrid inverter from 240 V to 600 V, promising solutions were adopted to reduce the power of the heat pump from 3.14 kW to 1.58 kW in the production of biogas 352.5 m3/day to maintain the temperature of the heating coolant entering the heat exchanger built into the methane tank at 55° C - 45 °C in order to obtain biogas, unload fermented wort and load fresh raw materials. There is an increase in the power of electricity transmission to the grid from 0.27 to 1 and an increase in the power factor by 40% from 0.58 to 0.98. The use of the developed Smart Grid technology allows preventing peak loads of the power system, reducing electricity consumption from the grid by up to 30%.
Impact of Ground Heat Source Addition on Main Performance Parameters of Solar Chimney Power Plants: A Numerical Study
Abstract: Solar energy systems can be an alternative to fossil fuels and are vital for a sustainable environment. It is promising that solar chimney power plants (SCPPs), which are among the solar energy systems, provide 24-hour power output (PO) and can work integrated with other systems. This study is based on the Manzanares pilot plant (MPP) and demonstrates satisfactory performance with an additional heat source to be integrated into the ground of the system during hours when solar radiation is weak. The performance of the system at different source temperatures is compared with the reference case, with the model verified using the RNG k-ε turbulence model through a 3D CFD study. In fact, it is seen that the PO of the system, which yields a PO of around 10 kW at 200 W/m2 solar radiation in the reference case, exceeds 80 kW with a source temperature of 200°C. From the results, it can be noticed that the system can also output power in the evening hours when there is no sun. With an additional heat source of 200°C during non-sunlit hours, the system gives more than 75 kW PO. This PO is 50% more than the maximum PO of 50 kW in the reference case.
Properties of ((CH3NH3)1-xCsx)3Bi2I9: (x=0-1.0) Hybrid Perovskite Solar Cells with Chlorobenzene Treatment
Abstract: Hybrid-perovskite solar cells, a promising lead-free perovskite material, have been attracted for optoelectronic applications due to an excellent optical and electrical properties with low production cost. Herein, methylammonium bismuth iodide and cesium bismuth iodide were mixed to form hybrid structure for the improvement of photovoltaic properties, which were fabricated using all-solution processed multi-step spin coating technique with changing the composition, x, of CBI, ((CH3NH3)1-xCsx)3Bi2I9; (x=0 – 1.0). Chlorobenzene was added to the solution to improve the surface morphology. By optimizing the composition of CBI in MBI, the morphology, structural and optical properties of HPeSCs have been improved. It showed that the morphology is homogeneous, compact and a uniform layer, while the crystallinity shows an improvement as well. The open circuit voltage, the short circuit current and the power conversion efficiency were much improved with using hybrid structure. Our study shows that the significance of the hybridization process gives a new route in fabricating a better active absorber layer of PeSCs in the future.
Design Principle and Development Trends of Silicon-Based Anode Binders for Lithium-ion Batteries: A Mini Review
Abstract: Silicon (Si), recognized as a promising alternative material for the anodes of lithium-ion batteries, boasts a high theoretical specific capacity and abundant natural availability. During the preparation of silicon-based anodes, binders play a pivotal role in ensuring the cohesion of silicon particles, conductive agents, and current collectors. The structure and performance of these binders are critical for the mechanical stability, electrical conductivity, and stress dissipation capacity of the anodes. This review initially outlines the structural characteristics of various binders, including linear, branched, and three-dimensional cross-linked types. It then delves into the relationship between the structure and properties of these binders in the context of their application in high-performance lithium-ion batteries, focusing on their mechanical properties, electrical conductivity, and self-healing capabilities. Particular attention is given to the design strategies for binders that facilitate stress dissipation, with an emphasis on integrating multifunctional polymer binders renowned for their superior conductive and self-healing features. Such binders contribute to the formation of a robust three-dimensional network structure via multiple bonding mechanisms, including chemical, non-covalent, and coordination interactions. This configuration significantly enhances the adhesion between silicon particles, thereby facilitating the efficient dissipation of stress, which is a key aspect for ensuring the long-term cycling stability of lithium-ion batteries. Lastly, the paper explores future development directions for silicon anode binders, advocating for a thorough investigation into the synergy of diverse structural and functional combinations, with the aim of advancing the performance and practical application of silicon-based lithium-ion batteries.
A Modified Perturb and Observe Algorithm in Photovoltaic Maximum Power Point Tracking System
Abstract: The power output of the photovoltaic (PV) array is nonlinear, and maximum power point tracking (MPPT) is required to boost the efficiency of solar energy generation. The traditional perturb and observe algorithm is frequently used, but it is difficult to comprehensively consider the tracking accuracy and response speed at the same time. Misjudgment occurs when the solar insolation changes drastically. In view of these shortcomings, this paper presents a variable step size threshold search algorithm. The modified algorithm can quickly track the maximum power point and restrain fluctuations near the maximum power point. Matlab is utilized to simulate and prove the effectiveness of this modified algorithm.
Abstract: This article presents preliminary results of the accelerated degradation of polymers using concentrated solar radiation. For this purpose, a passive solar concentration prototype was designed, which consists of four trapezoidal mirrors placed in the shape of an inverted truncated square pyramid. The mirrors are placed at an angle of 30° respect to the zenith. The prototype has a square base of 46 cm x 46 cm where the polymers to be irradiated are placed and a geometric concentration ratio, CRg, of 1.89. The mass change was determined after 30 days of exposure to solar radiation, and the temperature variation of some samples as a function of irradiance was obtained. In addition, a computer simulation was carried out using the free access software Energy2D. Some polymers maintained their flexible mechanical properties, such as PET (type 1), others were partially embrittled, while type 2, 5 and 7 polymers were completely embrittled. It was possible to reduce the degradation time of different types of commercial polymers, while polymers exposed to non-concentrated radiation and without exposure remains intact. Embrittled polymers can be used as waterproof material in slabs and pre-cast walls, as well in applications where they are not exposed to solar radiation. On the other hand, the polymers that remained intact must be used in applications with permanent radiation exposure, such as in flower pots, plastic parts for automobiles, etc.
Excellent Absorption of LaCoxO3 Over Full Solar Spectrum and Direct Photothermal Energy Storage of Ca(OH)2–LaCoxO3
Abstract: Photothermal conversion is a vital way for solar energy applications. The strong absorption of near Infrared light is essential for excellent photothermal performance. In this study, we demonstrated that nano LaCoxO3 is able to harvest light intensely across the full solar spectrum with high photothermal temperature. A core-shell-like structure of LaCoxO3-coated Ca(OH)2 particles was fabricated and shows excellent photothermal conversion, high kinetics of dehydration and remarkable cycle stability of heat storage and release. The photothermal dehydration-conversion of Ca(OH)2 increases 8.4-fold. Results demonstrate the multifunctionality of LaCoxO3, intensifying light harvesting, high photothermal conversion, good stability, considerable strength, and porous framework favouring the performance of photothermal storage and release cycles. LaCoxO3–Ca(OH)2 composite can simultaneously harvest light and store thermal energy.
Glucose Sensing Optionally in Optical and Optoelectrical Modes Based on Au-TiO2 Schottky Nanojunctions
Abstract: In recent years, metallic nanostructures have been extensively researched in the field of plasmonic for optical and optoelectronic applications such as biochemical sensing. However, an additional optoelectronic converter or spectrometer is usually required for the sensing application. Herein, the orderly-patterned Au-TiO2 Schottky junction with an Al film that we coupled, which simultaneously works as an optical reflector and conducting layer, can achieve optical sensing of glucose by exciting surface plasmon resonance associated with the environment, and meanwhile can realize glucose detection with direct electrical-signal readout by collecting the photogenerated carriers inside the Au nanostructures and TiO2 film. When used in optical mode, the designed sensor shows a sensing sensitivity of up to 1200.0 nmRIU-1 in numerical calculation, and the measured value is 346.1 nmRIU-1. When used in optoelectrical mode, the glucose sensor under one-sun illumination obtains a sensitivity of 70.0 µAM-1cm-2 in the concentration range of 0–10 mM, with a detection limit of 0.05 µM (Signal/Noise=3). Simulation and experimental results demonstrated that the Al-film-coupled Au-TiO2 Schottky nanojunction can monitor glucose concentration optionally in optical and optoelectrical modes, which presents an alternative route to the miniaturized, portable, and multi-functioned sensors.
Case Study of Optimized Cascaded Phase Change Thermal Energy Storage Unit
Phase change materials are paid increasing attention by the scholars in the past decades. For maintaining a relatively constant renewable energy output as a competent alternative for fossil fuel replacement, phase change storage unit are widely studied. However, for better pursuit of thermal energy performance and energy efficiency, only single staged phase change storage unit is not enough for increasing thermal requirements. Therefore, a triple staged phase change thermal energy storage unit have been proposed in this study. Meanwhile, correspondent comparison with single staged counterpart have been conducted along with related optimization. It has been concluded that the proposed thermal storage unit achieved 334.95 J/s & 41.54% / 186.37 J/s & 53.22 % in thermal energy exchange rate & exergy efficiency during endothermic/exothermic respectively. 3/21.4 L/min are the optimal circulating heat transfer fluid flowrates for endothermic/exothermic (better discharging rate)/ exothermic (better energy efficiency). Moreover, 100/9/15 are the best temperatures of circulating water for endothermic/ exothermic (better discharging rate)/ exothermic (better energy efficiency).
Fabrication of PVDF/PMMA Polymer for Sustainable Energy Harvesting
Abstract: The synthesis of blends that combine properties of two or more polymeric materials is increasingly investigated due to the versatility of the synthesis and its growing potential for many applications, including sustainability. Their characteristics are defined mainly by the synthesis conditions. Therefore, this paper details the synthesis process of easy-to-handle films using mixing method. The procedures and drawbacks found during the preparation of composite films are described. Polymeric compounds formed by the mixture of polyvinylidene fluoride (PVDF) and polymethyl methacrylate (PMMA) are addressed, varying the concentration, and evaluating their impact on the piezoelectric capacity. Films were formed through the spin-coating technique and characterized by optical and holographic microscopes. The results showed that composites with a concentration of 50 wt.% or larger of PVDF in the blend acquire a morphology with a granular appearance, however at lower concentrations they present a homogeneous morphology similar to that of PMMA. A homogeneous distribution of PVDF in the PMMA stands out. However, excessive contents of PMMA are associated to peaks and non-uniformities detected like multicolored regions by digital holography. Controlled strength-strain laboratory tests allowed to evaluate the film blends performance. The results indicate noticeable improvements in voltage output for a composition 70wt% PVDF and 30 wt% PMMA.
Smart Grid Functioning of Solar Electric System Network Based on Complex Accumulation Control
Abstract: Voltage maintenance in the distribution system takes place with the use of additional devices. The purpose of the work is to develop a Smart Grid functioning of the solar electric system network based on integrated storage control. Accumulator battery and thermoelectric accumulator as part of the solar electric system network acquire the additional status of voltage regulators in the distribution system. A comprehensive integrated system has been developed for supporting the functioning of the solar electric system network based on a prediction of changes in the battery capacity and power factor. Advanced decisions on change the capacity of the thermoelectric accumulator in redistributes the accumulated electrical energy. Changing the level of transmission of electric energy to the network make it possible to maintain voltage in the distribution system through maintaining the power factor of the network solar electric system. Continuous measurement of the voltage at the input to the hybrid inverter, the voltage at the output from the frequency converter and in the distribution system takes place. The change in the ratio of voltage at the output of the frequency converter and in the distribution system is evaluated. The peak load of the energy system is prevented, reducing the consumption of energy from the network to 14%.
Diameter-Dependent Shape Memory Effect and Superelasticity in Ni-Mn-Ga Alloy Micro-fibers
Abstract: The functional properties of shape memory alloys (SMAs) may be affected by the material size and thus is important for designing micron-sized devices. Here the diameter-dependent size effect was demonstrated in Ni-Mn-Ga fibers with diameters of 15, 41, 53 and 70μm. The effect of fiber diameter on the shape memory effect (SME) and superelasticity (SE) was systematically studied. The results showed that all Ni-Mn-Ga fibers exhibited good stress assisted thermal cycles and SE, both diameter-dependent. For stress assisted thermal cycles, the temperature hysteresis of martensite transformation (MT) and sensitivity of MT temperature vs stress increased with increasing fiber diameter. While for SE, the stress hysteresis, temperature dependence of critical stress and energy dissipation capacity decreased with increasing fiber diameter. Thermodynamic analysis revealed that the diameter-dependent effect may be attributed to the different heat exchange and frictional work dissipation capacities related to the specific surface areas that affected the thermal- or stress-induced MT processes. Such diameter dependence in Ni-Mn-Ga micro-fibers needs to be considered for the design and application in micro-sized devices.
UV Light-Induced Degradation of Industrial Silicon HJT Solar Cells: Degradation Mechanism and Recovery Strategies
Abstract: The demand for Silicon heterojunction solar cells (HJT) has significantly grown recently. These solar cells have gained recognition for their remarkable performance, which can be attributed to the exceptional passivation properties of bilayers consisting of intrinsic and doped hydrogenated amorphous silicon. This study investigates alternative recovery methods and looks into the deterioration caused by UV radiation in commercial Silicon HJT solar cells. The carrier lifetimes of the samples were measured before and after the HJT solar cells were exposed to ultraviolet radiation. The findings revealed a decrease in carrier lifetime, iVoc, and iFF, indicating the creation of defects in the bulk of a-Si:H and the interface between c-Si and a-Si:H. It was assessed how SiOx performed as a passivation layer. It has been discovered that SiOx can passivate dangling bonds, increase carrier lifetime and reduce trap density. In addition, recovery techniques like current injection, infrared, light soaking, and annealing were applied. The current injection, infrared, and light soaking treatments were discovered to be able to partially restore the efficiency of the solar cells without the combination of temperature, while annealing was found to be more effective. Additionally, the effects of both short and prolonged exposure to UV are investigated. The HJT solar cells exposed to prolonged UV radiation for an extended period of time could not fully regain their efficiency and displayed irreparable flaws. Overall, this study demonstrates the potential of recovery treatments and passivation techniques in increasing the efficiency of Si HJT solar cells and illuminates the processes underlying ultraviolet-induced deterioration. Overall, this study sheds light on ultraviolet-induced degradation mechanisms and highlights the potential of recovery treatments and passivation techniques in enhancing the efficiency of Si HJT solar cells.
CdS Covered with Ga-P Electron Exchange Membrane for Efficient Photocatalytic Hydrogen Prodection
Abstract: CdS is one of the best semiconductor photocatalysts. However, photocorrosion will occur when CdS takes part in the photocatalytic system. The general solution is to add sacrificial reagents to inhibit this phenomenon. Even so, it can not maintain the stability of CdS. In order to improve the stability and efficiency of CdS in pure water, Ga-P electron exchange membrane was designed to modify its surface. Under radiation of visible light, a significant increase can be observed in hydrogen production activity. In the absence of Pt as electron transfer agent, the modification of Ga-P realizes decomposition of pure water from zero to one. At the same time, the hydrogen production rate is increased about 5 times with Pt and catalytic life is greatly extended. Through proof of controlled experiment, Ga-P electron exchange membrane can not only prolong the lifetime of photogenerated electrons, but also change the direction of electrons. The formation of a protective membrane makes composite photocatalyst improve the stability and enhance the photocatalytic activity. Based on the analysis of TEM, fluorescence lifetime, UV-Vis diffuse reflection and photocurrent response, the mechanism is analyzed from atomic radius, nuclear orbit and energy level. For homogeneous electronic band structure and XPS analysis, we determined that the binary catalyst formed an S-scheme heterojunction. The work provides a potential way to design a more efficient and stable composite photocatalyst in the future. And contributed to the development of S-scheme heterojunctions.