随着传统化石能源面临枯竭的问题日益加剧,使用太阳能进行光伏发电成为世界各国能源结构调整的重要方向,如何进一步提高光伏发电功率的预测精度成为亟待解决的问题。为提高光伏功率短期预测的准确性和可靠性,提出一种耦合太阳辐射预报...随着传统化石能源面临枯竭的问题日益加剧,使用太阳能进行光伏发电成为世界各国能源结构调整的重要方向,如何进一步提高光伏发电功率的预测精度成为亟待解决的问题。为提高光伏功率短期预测的准确性和可靠性,提出一种耦合太阳辐射预报模式系统(weather research and forecasting model for solar energy,WRF-Solar)及辐照度订正的光伏短期预测模型,先使用WRF-Solar进行动力降尺度天气数值预报,得到包含辐照度等在内的未来气象因子,再利用随机森林对预报辐照度进行订正,在此基础上运用长短期神经网络、反向传播神经网络和逐步聚类分析建立光伏功率短期预测模型,利用某40 MW光伏电站的实际运行数据进行模型对比分析。结果表明,使用随机森林模型订正后的辐照度更接近真实值,平均绝对误差率下降了56.06个百分点;与另外2种模型预测结果对比发现,长短期神经网络模型预测效果最好,平均绝对百分比误差降低了4.13个百分点,说明组合模型能够进一步提高功率预测的精度。展开更多
Major solar plasma disturbances are subjected to Lomb-Scargle periodogram and wavelet analysis to determine the occurrence frequency.These disruptions include interplanetary coronal mass ejection,sudden storm commence...Major solar plasma disturbances are subjected to Lomb-Scargle periodogram and wavelet analysis to determine the occurrence frequency.These disruptions include interplanetary coronal mass ejection,sudden storm commencement,high-speed streams,corotating interaction regions,interplanetary shocks and Forbush decreases.We included information on all of the aforementioned solar disturbances for the last six solar cycles,from 1965 to 2023,for this study.Our findings reveal some intriguing and noteworthy results that clearly distinguish between even and odd-numbered solar cycles.The study suggests that the Sun behaves differently in odd and even-numbered solar cycles as it comes from the massive solar eruptions.During even-numbered solar cycles,variations with a period of∼44 days are prominently observed in addition to solar rotation(∼27 days)and extended solar(∼36 days)rotation.However,in addition to solar rotation,prolonged solar rotation,and periods of around 44 days,we also detect a number of intermittent changes with nearly comparable amplitude during the oddnumbered solar cycles.The findings also demonstrate that,in contrast to odd-numbered solar cycles,the emissions rate of these disruptions is more distinct and predictable during even-numbered solar cycles.展开更多
We investigate the relationship between the magnitudes of Forbush decreases(FDs)and solar-geomagnetic characteristics using daily-averaged galactic cosmic ray(GCR)data from Inuvick(INVK)and Magadan(MGDN)neutron monito...We investigate the relationship between the magnitudes of Forbush decreases(FDs)and solar-geomagnetic characteristics using daily-averaged galactic cosmic ray(GCR)data from Inuvick(INVK)and Magadan(MGDN)neutron monitor(NM)stations to aid in counting the case of GCR flux intensity modulation.The FDs,obtained with an automated new computer software algorithm from daily-averaged GCR data from the IZMIRAN common website:http://cr0.izmiran.ru/common,at INVK(224)and MGDN(229)NM stations,from 1998 to 2002,were used in the present work.The associated solar-geomagnetic parameters of the same time range were obtained from the OMNI website.A statistical analytical method was employed to test the link between FD amplitudes and solargeomagnetic variables.We observed negative trends in FD-IMF,FD-SWS,FD-Kp,FD-SSN and FD-SI,while a positive relation was indicated in FD-Dst at both stations.All are statistically significant at a 95%confidence level.The results obtained here imply that solar emission characteristics impact the GCR flux intensity modulation.展开更多
To improve the photovoltaic conversion efficiency(PCE)of silicon heterojunction(SHJ)solar cells,this study focuses on optimizing the physical parameters of the sun-side-doped layer and proposes strategies to address t...To improve the photovoltaic conversion efficiency(PCE)of silicon heterojunction(SHJ)solar cells,this study focuses on optimizing the physical parameters of the sun-side-doped layer and proposes strategies to address the challenges posed by Fermi level pinning in wide bandgap designs.Using AFORS-HET simulations,we systematically investigate the effects of bandgap width,doping concentration,and defect state distribution on the energy band structure,interface electric field,and carrier transport dynamics.The results reveal that maintaining the Fermi level within 0.3 eV of the conduction band is essential for optimal device performance.A wider bandgap(>1.8 eV)enhances the utilization of short-wavelength light and significantly suppresses interface recombination,leading to an increase in short-circuit current density(J_(sc))by 0.8 mA/cm^(2).This benefit comes with a delicate balance between minimizing defect state density and improving doping efficiency.This study provides theoretical insights into the optimization of doped layer physical parameters and proposes practical solutions,including nano-crystallization and low-doping interface strategies,to improve the performance of SHJ solar cells and support industrial applications.展开更多
Sb_(2)S_(3)films are susceptible to the formation of nanogap defects during the crystallization process,leading to their experimental power conversion efficiency(PCE)falling significantly short of the theoretical limi...Sb_(2)S_(3)films are susceptible to the formation of nanogap defects during the crystallization process,leading to their experimental power conversion efficiency(PCE)falling significantly short of the theoretical limit.This investigation presents,a groundbreaking Sb_(2)S_(3)photovoltaic device model that integrates perovskite within these nanogaps,and systematically examines the mechanisms for enhancing the PCE.Our findings reveal that incorporating perovskite within the nanogaps yields a 10%enhancement in optical absorption performance.Furthermore,perovskite nanogaps function as effective electron transport channels,significantly reducing the recombination of photogenerated carriers within the highly defective Sb_(2)S_(3).The dimensions and arrangement of the nanochannels play a pivotal role in determining device performance,with optimal measurements of 5 nm in width and 15 nm in spacing.Additionally,this study examines the universality of the nanochannel structure.The projected PCE of this innovative structure is an impressive 25.40%.These findings provide valuable theoretical guidance for designing high-efficiency Sb_(2)S_(3)solar cells.展开更多
The structural design of n-i-p in antimony selenide(Sb_(2)Se_(3))thin film solar cells can effectively improve the low carrier collection efficiency caused by the lower doping concentration of Sb_(2)Se_(3).However,the...The structural design of n-i-p in antimony selenide(Sb_(2)Se_(3))thin film solar cells can effectively improve the low carrier collection efficiency caused by the lower doping concentration of Sb_(2)Se_(3).However,the unideal carrier transport ability of the intrinsic light-absorbing layer remains a major limitation for its power conversion efficiency improvement.Herein,it is discovered that the carrier transport in Sb_(2)Se_(3)thin films strongly depends on the film thickness of the absorber layer in n-i-p structure.By exploring the carrier transport mechanism under different thicknesses of light-absorbing layers,a suitable absorber layer with thickness of 550 nm is demonstrated can effectively separate,transport,and extract photogenerated carriers in Sb_(2)Se_(3)solar cells.Finally,the vapor transport deposition processed Sb_(2)Se_(3)solar cells achieve the highest PCE of 7.62%with a short-circuit current density of 30.71 mA·cm^(-2).This finding provides a constructive guidance for the future researches on Sb_(2)Se_(3)thin film solar cells with n-i-p structure.展开更多
Attempts to remove environmentally harmful materials in mass production industries are always a major issue and draw attention if the substitution guarantees a chance to lower fabrication cost and to improve device pe...Attempts to remove environmentally harmful materials in mass production industries are always a major issue and draw attention if the substitution guarantees a chance to lower fabrication cost and to improve device performance,as in a wide bandgap Zn_(1-x)Mg_(x)O(ZMO)to replace the CdS buffer in Cu(In_(1-x),Ga_(x))Se_(2)(CIGSe)thin-film solar cell structure.ZMO is one of the candidates for the buffer material in CIGSe thin-film solar cells with a wide and controllable bandgap depending on the Mg content,which can be helpful in attaining a suitable conduction band offset.Hence,compared to the fixed and limited bandgap of a CdS buffer,a ZMO buffer may provide advantages in V_(oc) and J_(sc) based on its controllable and wide bandgap,even with a relatively wider bandgap CIGSe thin-film solar cell.In addition,to solve problems with the defect sites at the ZMO/CIGSe junction interface,a few-nanometer ZnS layer is employed for heterojunction interface passivation,forming a ZMO/ZnS buffer structure by atomic layer deposition(ALD).Finally,a Cd-free all-dry-processed CIGSe solar cell with a wider bandgap(1.25 eV)and ALD-grown buffer structure exhibited the best power conversion efficiency of 19.1%,which exhibited a higher performance than the CdS counterpart.展开更多
In this study we review the occurrence of different types (A, B, C, M, and X classes) of solar flares during different solar cycle phases from 1996 to 2019 covering the solar cycles 23 and 24. During this period, a to...In this study we review the occurrence of different types (A, B, C, M, and X classes) of solar flares during different solar cycle phases from 1996 to 2019 covering the solar cycles 23 and 24. During this period, a total of 19,126 solar flares were observed regardless the class: 3548 flares in solar cycle 23 (SC23) and 15,668 flares in solar cycle 24 (SC24). Our findings show that the cycle 23 has observed the highest occurrences of M-class and X-class flares, whereas cycle 24 has pointed out a predominance of B-class and C-class flares throughout its different phases. The results indicate that the cycle 23 was magnetically more intense than cycle 24, leading to more powerful solar flares and more frequent geomagnetic storms, capable of generating significant electromagnetic emissions that can affect satellites and GPS signals. The decrease in intense solar flares during cycle 24 compared to cycle 23 reflects an evolution in solar activity patterns over time.展开更多
The effect of a storage system on drying time and estimation of drying parameters of cocoa beans using an indirect solar dryer with a sensible heat energy storage system (stones which act as both absorber and heat sto...The effect of a storage system on drying time and estimation of drying parameters of cocoa beans using an indirect solar dryer with a sensible heat energy storage system (stones which act as both absorber and heat storage media) is the main subject of this article. This dryer, which uses stones as storage material and is made of wood and plywood, was used to dry a quantity of 5 kg of fermented cocoa beans. The drying parameters for the drying curves and the drying efficiency of cocoa beans were established and studied. The drying curves were modelled from semi-empirical models. The results showed that the moisture of cocoa beans decreased from 60% to 7% in wet basis. With a solar collector and drying efficiency of 40% and 34%, respectively. And this with a maximum average difference temperature between the drying air and the ambient temperature of 13.25˚C day or night. The best concordances are obtained with R2 values of 0.9983, 0.9843, 0.9813 and 0.9837 respectively from the models of Hii, Jena and Das, Demir et al. and Alibas.展开更多
Solar cells made from perovskites have experienced rapid development as examples of third-generation solar cells in recent years. The traditional trial-and-error method is inefficient, and the search space is incredib...Solar cells made from perovskites have experienced rapid development as examples of third-generation solar cells in recent years. The traditional trial-and-error method is inefficient, and the search space is incredibly large. This makes developing advanced perovskite materials, as well as high conversion efficiencies and stability of perovskite solar cells (PSCs), a challenging task. A growing number of data-driven machine learning (ML) applications are being developed in the materials science field, due to the availability of large databases and increased computing power. There are many advantages associated with the use of machine learning to predict the properties of potential perovskite materials, as well as provide additional knowledge on how these materials work to fast-track their progress. Thus, the purpose of this paper is to develop a conceptual model to improve the efficiency of a perovskite solar cell using machine learning techniques in order to improve its performance. This study relies on the application of design science as a method to conduct the research as part of the study. The developed model consists of six phases: Data collection and preprocessing, feature selection and engineering, model training and evaluation, performance assessment, optimization and fine-tuning, and deployment and application. As a result of this model, there is a great deal of promise in advancing the field of perovskite solar cells as well as providing a basis for developing more efficient and cost-effective solar energy technologies in the future.展开更多
Solar stills represent a promising solution for desalinating saline waters, providing a sustainable alternative in regions with limited access to drinking water. This study evaluates the reliability of a two-dimension...Solar stills represent a promising solution for desalinating saline waters, providing a sustainable alternative in regions with limited access to drinking water. This study evaluates the reliability of a two-dimensional (2D) numerical model of a solar still, developed using COMSOL® Multiphysics software, focusing on a passive cascading device called “Pano Rano.” Two physical prototypes were constructed: one with a standard concrete basin and the other with acrylic plastic. The simulations revealed significant differences in theoretical yield based on the material used. With a radiation of 1200 W/m2, the acrylic prototype displayed an evaporation of 4455.53 mL/m2 and a production of 2925.98 mL/m2 of distilled water, while the concrete model showed an evaporation of 2109.95 mL/m2 and produced 1383.93 mL/m2 of distilled water. The results indicate that evaporation significantly exceeds condensation, highlighting an underutilized evaporation potential. The evaluation of the numerical model’s performance against experimental results was conducted using the mean squared error (MSE) and the coefficient of determination (R2). The best performance was observed in summer (MSE of 16.24;R2 of 0.95), while winter results were less convincing (MSE of 204.77;R2 of −2.78). This variability underscores the model’s limitations and the need for future research. The study also demonstrates that the choice of basin material significantly influences productivity, with acrylic plastic outperforming concrete in terms of thermal efficiency.展开更多
The study was carried out in the Tahoua region at the market gardening sites of the Taddis 1 and 2 valley. Small-scale pumping irrigation is one of the most interesting uses of solar energy. The objective of this stud...The study was carried out in the Tahoua region at the market gardening sites of the Taddis 1 and 2 valley. Small-scale pumping irrigation is one of the most interesting uses of solar energy. The objective of this study is to carry out a comparative analysis of two dewatering pumping systems (Solar Kit and GMP) for water mobilization on a certain number of criteria such as sustainable use, economic aspect and performance. To achieve this, the adapted methodology consisted first of all in the development of a data collection tool in the field. Then flow measurements, estimation of fuel consumption, pressure height, etc., were carried out. Thus, the data collection involved a sample of 120 irrigators who had to use the two (2) types of pumping systems. The collected data were analyzed and processed with appropriate software. The results of the study show that the two pumping systems studied have strengths and constraints. Thus, the solar pumping system has a significant investment cost, very low maintenance and a low operating cost. On the other hand, the system with a generator has a relatively low investment cost (25 to 30 times less than solar), but a relatively high operating, upkeep and maintenance cost. He adds that these assets and constraints must be taken into consideration when an investment is made. This study shows that 74% of producers use GMP compared to 26% who use the Solar Kit. But in practice, the Solar Kit is more reliable for producers from the point of view of planted area, environmental management and investment costs, supply of fuel and lubricant. These results indicate better performance of the solar pumping system compared to GMP at the study sites.展开更多
In this study, we examined variability of sun-related energies, auroral electrojet current, ring current, and magnetopause current during solar cycles 23 and 24. The study revealed a dependence of sun-related energies...In this study, we examined variability of sun-related energies, auroral electrojet current, ring current, and magnetopause current during solar cycles 23 and 24. The study revealed a dependence of sun-related energies to the Sun and Earth currents systems with solar activity from 1996 to 2019. A decrease in the correlation between sun-related energies and sunspot number was observed over solar cycles 23 and 24 (0.88 for the solar cycle 23 and 0.66 for the solar cycle 24), with a drop in the speed of magnetic disturbances in the solar wind. These results could be attributed to the decrease in Sun’s magnetic field toroidal component magnitude induced by a weak in sunspots number and solar flares during the solar cycle 24. A weak in the Earth currents systems (auroral electrojet current, ring current, and magnetopause current) is also observed. During the decrease in the Earth currents, several peaks are observed, indicating a nonlinear dependence in the Earth currents variation (ring current, auroral electrojet current, and magnetopause current) from solar cycle 23 to solar cycle 24. This could be attributed to the Corotating Interaction Regions (CIRs) observed during the declining phase of solar cycle 23 and the deep minimum preceding solar cycle 24.展开更多
Solar energy is a pivotal clean energy source in the transition to carbon neutrality from fossil fuels.However,the intermittent and stochastic characteristics of solar radiation pose challenges for accurate simulation...Solar energy is a pivotal clean energy source in the transition to carbon neutrality from fossil fuels.However,the intermittent and stochastic characteristics of solar radiation pose challenges for accurate simulation and prediction.Accurately simulating and predicting solar radiation and its variability are crucial for optimizing solar energy utilization.This study conducted simulation experiments using the WRF-Solar model from 25 June to 25 July 2022,to evaluate the accuracy and performance of the simulated solar radiation across China.The simulations covered the whole country with a grid spacing of 27 km and were compared with ground observation network data from the Chinese Ecosystem Research Network.The results indicated that WRF-Solar can accurately capture the spatiotemporal patterns of global horizontal irradiance over China,but there is still an overestimation of solar radiation,and the model underestimates the total cloud cover.The root-mean-square error ranged from 92.83 to 188.13 W m^(-2) and the mean bias(MB)ranged from 21.05 to 56.22 W m^(-2).The simulation showed the smallest MB at Lhasa on the Qinghai–Tibet Plateau,while the largest MB was observed in Southeast China.To enhance the accuracy of solar radiation simulation,the authors compared the Fast All-sky Radiation Model for Solar with the Rapid Radiative Transfer Model for General Circulation Models and found that the former provides better simulation.展开更多
文摘随着传统化石能源面临枯竭的问题日益加剧,使用太阳能进行光伏发电成为世界各国能源结构调整的重要方向,如何进一步提高光伏发电功率的预测精度成为亟待解决的问题。为提高光伏功率短期预测的准确性和可靠性,提出一种耦合太阳辐射预报模式系统(weather research and forecasting model for solar energy,WRF-Solar)及辐照度订正的光伏短期预测模型,先使用WRF-Solar进行动力降尺度天气数值预报,得到包含辐照度等在内的未来气象因子,再利用随机森林对预报辐照度进行订正,在此基础上运用长短期神经网络、反向传播神经网络和逐步聚类分析建立光伏功率短期预测模型,利用某40 MW光伏电站的实际运行数据进行模型对比分析。结果表明,使用随机森林模型订正后的辐照度更接近真实值,平均绝对误差率下降了56.06个百分点;与另外2种模型预测结果对比发现,长短期神经网络模型预测效果最好,平均绝对百分比误差降低了4.13个百分点,说明组合模型能够进一步提高功率预测的精度。
文摘Major solar plasma disturbances are subjected to Lomb-Scargle periodogram and wavelet analysis to determine the occurrence frequency.These disruptions include interplanetary coronal mass ejection,sudden storm commencement,high-speed streams,corotating interaction regions,interplanetary shocks and Forbush decreases.We included information on all of the aforementioned solar disturbances for the last six solar cycles,from 1965 to 2023,for this study.Our findings reveal some intriguing and noteworthy results that clearly distinguish between even and odd-numbered solar cycles.The study suggests that the Sun behaves differently in odd and even-numbered solar cycles as it comes from the massive solar eruptions.During even-numbered solar cycles,variations with a period of∼44 days are prominently observed in addition to solar rotation(∼27 days)and extended solar(∼36 days)rotation.However,in addition to solar rotation,prolonged solar rotation,and periods of around 44 days,we also detect a number of intermittent changes with nearly comparable amplitude during the oddnumbered solar cycles.The findings also demonstrate that,in contrast to odd-numbered solar cycles,the emissions rate of these disruptions is more distinct and predictable during even-numbered solar cycles.
文摘We investigate the relationship between the magnitudes of Forbush decreases(FDs)and solar-geomagnetic characteristics using daily-averaged galactic cosmic ray(GCR)data from Inuvick(INVK)and Magadan(MGDN)neutron monitor(NM)stations to aid in counting the case of GCR flux intensity modulation.The FDs,obtained with an automated new computer software algorithm from daily-averaged GCR data from the IZMIRAN common website:http://cr0.izmiran.ru/common,at INVK(224)and MGDN(229)NM stations,from 1998 to 2002,were used in the present work.The associated solar-geomagnetic parameters of the same time range were obtained from the OMNI website.A statistical analytical method was employed to test the link between FD amplitudes and solargeomagnetic variables.We observed negative trends in FD-IMF,FD-SWS,FD-Kp,FD-SSN and FD-SI,while a positive relation was indicated in FD-Dst at both stations.All are statistically significant at a 95%confidence level.The results obtained here imply that solar emission characteristics impact the GCR flux intensity modulation.
基金supported by the National Natural Science Foundation of China(Grant Nos.61991441 and 62004218)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB01000000)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2021005).
文摘To improve the photovoltaic conversion efficiency(PCE)of silicon heterojunction(SHJ)solar cells,this study focuses on optimizing the physical parameters of the sun-side-doped layer and proposes strategies to address the challenges posed by Fermi level pinning in wide bandgap designs.Using AFORS-HET simulations,we systematically investigate the effects of bandgap width,doping concentration,and defect state distribution on the energy band structure,interface electric field,and carrier transport dynamics.The results reveal that maintaining the Fermi level within 0.3 eV of the conduction band is essential for optimal device performance.A wider bandgap(>1.8 eV)enhances the utilization of short-wavelength light and significantly suppresses interface recombination,leading to an increase in short-circuit current density(J_(sc))by 0.8 mA/cm^(2).This benefit comes with a delicate balance between minimizing defect state density and improving doping efficiency.This study provides theoretical insights into the optimization of doped layer physical parameters and proposes practical solutions,including nano-crystallization and low-doping interface strategies,to improve the performance of SHJ solar cells and support industrial applications.
基金Project(52203250)supported by the National Natural Science Foundation of ChinaProject(BS2024074)supported by the Ordos City New Energy Strategic Leading Technology Special Project,China+3 种基金Project(2025YFHH0119)supported by the Key Research and Development and Achievement Transformation Program of Inner Mongolia Autonomous Region,ChinaProject(2022ZY0187)supported by the Central Guiding Local Science and Technology Development Fund of Inner Mongolia Autonomous Region,ChinaProject(JY20220211)supported by the Basic Study Fund of Universities of Inner Mongolia Autonomous Region,ChinaProjects(JBGS-2023-005,JY20230026)supported by the Major“Unveiling”Project of Ordos City,China。
文摘Sb_(2)S_(3)films are susceptible to the formation of nanogap defects during the crystallization process,leading to their experimental power conversion efficiency(PCE)falling significantly short of the theoretical limit.This investigation presents,a groundbreaking Sb_(2)S_(3)photovoltaic device model that integrates perovskite within these nanogaps,and systematically examines the mechanisms for enhancing the PCE.Our findings reveal that incorporating perovskite within the nanogaps yields a 10%enhancement in optical absorption performance.Furthermore,perovskite nanogaps function as effective electron transport channels,significantly reducing the recombination of photogenerated carriers within the highly defective Sb_(2)S_(3).The dimensions and arrangement of the nanochannels play a pivotal role in determining device performance,with optimal measurements of 5 nm in width and 15 nm in spacing.Additionally,this study examines the universality of the nanochannel structure.The projected PCE of this innovative structure is an impressive 25.40%.These findings provide valuable theoretical guidance for designing high-efficiency Sb_(2)S_(3)solar cells.
基金supported by the National Natural Science Foundation of China(No.62305064)the Beijing Nova Program from Beijing Municipal Science&Technology Commission(No.Z211100002121072).
文摘The structural design of n-i-p in antimony selenide(Sb_(2)Se_(3))thin film solar cells can effectively improve the low carrier collection efficiency caused by the lower doping concentration of Sb_(2)Se_(3).However,the unideal carrier transport ability of the intrinsic light-absorbing layer remains a major limitation for its power conversion efficiency improvement.Herein,it is discovered that the carrier transport in Sb_(2)Se_(3)thin films strongly depends on the film thickness of the absorber layer in n-i-p structure.By exploring the carrier transport mechanism under different thicknesses of light-absorbing layers,a suitable absorber layer with thickness of 550 nm is demonstrated can effectively separate,transport,and extract photogenerated carriers in Sb_(2)Se_(3)solar cells.Finally,the vapor transport deposition processed Sb_(2)Se_(3)solar cells achieve the highest PCE of 7.62%with a short-circuit current density of 30.71 mA·cm^(-2).This finding provides a constructive guidance for the future researches on Sb_(2)Se_(3)thin film solar cells with n-i-p structure.
基金conducted under the framework of the research and development program of the Korea Institute of Energy Research(C4-2412 and C4-2413)supported by the National Research Foundation of Korea(grant number 2022M3J1A1063019)funded by the Ministry of Science and ICT.
文摘Attempts to remove environmentally harmful materials in mass production industries are always a major issue and draw attention if the substitution guarantees a chance to lower fabrication cost and to improve device performance,as in a wide bandgap Zn_(1-x)Mg_(x)O(ZMO)to replace the CdS buffer in Cu(In_(1-x),Ga_(x))Se_(2)(CIGSe)thin-film solar cell structure.ZMO is one of the candidates for the buffer material in CIGSe thin-film solar cells with a wide and controllable bandgap depending on the Mg content,which can be helpful in attaining a suitable conduction band offset.Hence,compared to the fixed and limited bandgap of a CdS buffer,a ZMO buffer may provide advantages in V_(oc) and J_(sc) based on its controllable and wide bandgap,even with a relatively wider bandgap CIGSe thin-film solar cell.In addition,to solve problems with the defect sites at the ZMO/CIGSe junction interface,a few-nanometer ZnS layer is employed for heterojunction interface passivation,forming a ZMO/ZnS buffer structure by atomic layer deposition(ALD).Finally,a Cd-free all-dry-processed CIGSe solar cell with a wider bandgap(1.25 eV)and ALD-grown buffer structure exhibited the best power conversion efficiency of 19.1%,which exhibited a higher performance than the CdS counterpart.
文摘In this study we review the occurrence of different types (A, B, C, M, and X classes) of solar flares during different solar cycle phases from 1996 to 2019 covering the solar cycles 23 and 24. During this period, a total of 19,126 solar flares were observed regardless the class: 3548 flares in solar cycle 23 (SC23) and 15,668 flares in solar cycle 24 (SC24). Our findings show that the cycle 23 has observed the highest occurrences of M-class and X-class flares, whereas cycle 24 has pointed out a predominance of B-class and C-class flares throughout its different phases. The results indicate that the cycle 23 was magnetically more intense than cycle 24, leading to more powerful solar flares and more frequent geomagnetic storms, capable of generating significant electromagnetic emissions that can affect satellites and GPS signals. The decrease in intense solar flares during cycle 24 compared to cycle 23 reflects an evolution in solar activity patterns over time.
文摘The effect of a storage system on drying time and estimation of drying parameters of cocoa beans using an indirect solar dryer with a sensible heat energy storage system (stones which act as both absorber and heat storage media) is the main subject of this article. This dryer, which uses stones as storage material and is made of wood and plywood, was used to dry a quantity of 5 kg of fermented cocoa beans. The drying parameters for the drying curves and the drying efficiency of cocoa beans were established and studied. The drying curves were modelled from semi-empirical models. The results showed that the moisture of cocoa beans decreased from 60% to 7% in wet basis. With a solar collector and drying efficiency of 40% and 34%, respectively. And this with a maximum average difference temperature between the drying air and the ambient temperature of 13.25˚C day or night. The best concordances are obtained with R2 values of 0.9983, 0.9843, 0.9813 and 0.9837 respectively from the models of Hii, Jena and Das, Demir et al. and Alibas.
文摘Solar cells made from perovskites have experienced rapid development as examples of third-generation solar cells in recent years. The traditional trial-and-error method is inefficient, and the search space is incredibly large. This makes developing advanced perovskite materials, as well as high conversion efficiencies and stability of perovskite solar cells (PSCs), a challenging task. A growing number of data-driven machine learning (ML) applications are being developed in the materials science field, due to the availability of large databases and increased computing power. There are many advantages associated with the use of machine learning to predict the properties of potential perovskite materials, as well as provide additional knowledge on how these materials work to fast-track their progress. Thus, the purpose of this paper is to develop a conceptual model to improve the efficiency of a perovskite solar cell using machine learning techniques in order to improve its performance. This study relies on the application of design science as a method to conduct the research as part of the study. The developed model consists of six phases: Data collection and preprocessing, feature selection and engineering, model training and evaluation, performance assessment, optimization and fine-tuning, and deployment and application. As a result of this model, there is a great deal of promise in advancing the field of perovskite solar cells as well as providing a basis for developing more efficient and cost-effective solar energy technologies in the future.
文摘Solar stills represent a promising solution for desalinating saline waters, providing a sustainable alternative in regions with limited access to drinking water. This study evaluates the reliability of a two-dimensional (2D) numerical model of a solar still, developed using COMSOL® Multiphysics software, focusing on a passive cascading device called “Pano Rano.” Two physical prototypes were constructed: one with a standard concrete basin and the other with acrylic plastic. The simulations revealed significant differences in theoretical yield based on the material used. With a radiation of 1200 W/m2, the acrylic prototype displayed an evaporation of 4455.53 mL/m2 and a production of 2925.98 mL/m2 of distilled water, while the concrete model showed an evaporation of 2109.95 mL/m2 and produced 1383.93 mL/m2 of distilled water. The results indicate that evaporation significantly exceeds condensation, highlighting an underutilized evaporation potential. The evaluation of the numerical model’s performance against experimental results was conducted using the mean squared error (MSE) and the coefficient of determination (R2). The best performance was observed in summer (MSE of 16.24;R2 of 0.95), while winter results were less convincing (MSE of 204.77;R2 of −2.78). This variability underscores the model’s limitations and the need for future research. The study also demonstrates that the choice of basin material significantly influences productivity, with acrylic plastic outperforming concrete in terms of thermal efficiency.
文摘The study was carried out in the Tahoua region at the market gardening sites of the Taddis 1 and 2 valley. Small-scale pumping irrigation is one of the most interesting uses of solar energy. The objective of this study is to carry out a comparative analysis of two dewatering pumping systems (Solar Kit and GMP) for water mobilization on a certain number of criteria such as sustainable use, economic aspect and performance. To achieve this, the adapted methodology consisted first of all in the development of a data collection tool in the field. Then flow measurements, estimation of fuel consumption, pressure height, etc., were carried out. Thus, the data collection involved a sample of 120 irrigators who had to use the two (2) types of pumping systems. The collected data were analyzed and processed with appropriate software. The results of the study show that the two pumping systems studied have strengths and constraints. Thus, the solar pumping system has a significant investment cost, very low maintenance and a low operating cost. On the other hand, the system with a generator has a relatively low investment cost (25 to 30 times less than solar), but a relatively high operating, upkeep and maintenance cost. He adds that these assets and constraints must be taken into consideration when an investment is made. This study shows that 74% of producers use GMP compared to 26% who use the Solar Kit. But in practice, the Solar Kit is more reliable for producers from the point of view of planted area, environmental management and investment costs, supply of fuel and lubricant. These results indicate better performance of the solar pumping system compared to GMP at the study sites.
文摘In this study, we examined variability of sun-related energies, auroral electrojet current, ring current, and magnetopause current during solar cycles 23 and 24. The study revealed a dependence of sun-related energies to the Sun and Earth currents systems with solar activity from 1996 to 2019. A decrease in the correlation between sun-related energies and sunspot number was observed over solar cycles 23 and 24 (0.88 for the solar cycle 23 and 0.66 for the solar cycle 24), with a drop in the speed of magnetic disturbances in the solar wind. These results could be attributed to the decrease in Sun’s magnetic field toroidal component magnitude induced by a weak in sunspots number and solar flares during the solar cycle 24. A weak in the Earth currents systems (auroral electrojet current, ring current, and magnetopause current) is also observed. During the decrease in the Earth currents, several peaks are observed, indicating a nonlinear dependence in the Earth currents variation (ring current, auroral electrojet current, and magnetopause current) from solar cycle 23 to solar cycle 24. This could be attributed to the Corotating Interaction Regions (CIRs) observed during the declining phase of solar cycle 23 and the deep minimum preceding solar cycle 24.
基金supported by the National Natural Science Foundation of China[grant number 42175132]the National Key R&D Program[grant number 2020YFA0607802]the CAS Information Technology Program[grant number CAS-WX2021SF-0107-02]。
文摘Solar energy is a pivotal clean energy source in the transition to carbon neutrality from fossil fuels.However,the intermittent and stochastic characteristics of solar radiation pose challenges for accurate simulation and prediction.Accurately simulating and predicting solar radiation and its variability are crucial for optimizing solar energy utilization.This study conducted simulation experiments using the WRF-Solar model from 25 June to 25 July 2022,to evaluate the accuracy and performance of the simulated solar radiation across China.The simulations covered the whole country with a grid spacing of 27 km and were compared with ground observation network data from the Chinese Ecosystem Research Network.The results indicated that WRF-Solar can accurately capture the spatiotemporal patterns of global horizontal irradiance over China,but there is still an overestimation of solar radiation,and the model underestimates the total cloud cover.The root-mean-square error ranged from 92.83 to 188.13 W m^(-2) and the mean bias(MB)ranged from 21.05 to 56.22 W m^(-2).The simulation showed the smallest MB at Lhasa on the Qinghai–Tibet Plateau,while the largest MB was observed in Southeast China.To enhance the accuracy of solar radiation simulation,the authors compared the Fast All-sky Radiation Model for Solar with the Rapid Radiative Transfer Model for General Circulation Models and found that the former provides better simulation.
