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The clean energy transitions require a large volume of minerals to handle its diverse technologies, such as solar photovoltaics (PV), wind turbines etc. Therefore, mineral importing countries concentrated on cleaner energy production confront an uprising trend in critical mineral prices due to thriving demands. We quest for the response of the top mineral importing countries' import demand for minerals to the clean energy transitions from 1996 to 2019 within the import-demand function analysis. Using the cross-sectional autoregressive distributed lag (CS-ARDL) method, our findings divulge a significantly positive response of mineral import demand to solar and wind energy productions in the long run. We also find that mineral price elasticity holds the Marshallian demand hypothesis in the mineral-laden solar energy generation while contradicting it in wind energy production. In addition, the oil price substitution effect does not sustain, whereas exchange rate depreciates mineral import demands in the long run. Therefore, our policy implications encompass optimizing the mineral resources for clean energy transitions to materialize the 21st century's global agenda of a decarbonized or net-zero emissions trajectory. © 2022 Elsevier Ltd Ministry of Education and Science of the Russian Federation, Minobrnauka; Ural Federal University, UrFU Acknowledgement: The research funding from the Ministry of Science and Higher Education of the Russian Federation (Ural Federal University project within the Priority-2030 Program) is gratefully acknowledged.

This paper presents the performances of a new passive anti-islanding protection with minimal switching losses for three-phase grid-connected photovoltaic power systems. The novelty of the proposed strategy consists of five conventional passive relays, which are as follows: over/under current, over/under voltage, over/under frequency, rate of change of frequency, and dc-link voltage-based anti-islanding methods. Integrating these methods in a synergistic way reduces the limitations of each method, while combining the strengths and benefits of each method in islanding detection. As such, the dc-link voltage-based method consists in supervising the dc-link voltage in voltage source converters to reduce the voltage stress and increase performance. The performance in islanding prevention is determined by the detection time of islanding operation mode. The proposed anti-islanding protection was simulated under complete disconnection of the photovoltaic inverter from the electrical power system, as well as under grid faults as required by new grid codes.

Five novel D-?-A structured pyridinium based compounds, bearing different electron-donating units were synthesized, minutely characterized, and their solvatochromic and electronic properties were investigated. Subsequently, these compounds were added to a liquid electrolyte in order to enhance the photovoltaic performance of the N719-sensitized solar cell. It was demonstrated that the utilization of all compounds improved the conversion efficiency, compared to the reference solar cell comprised of plain liquid electrolyte. The photovoltaic performance of the fabricated DSSC depended of the electron-donating moiety of the synthesized compound. The highest photovoltaic conversion efficiency of 4.11% was obtained for DSSC with the compound bearing the 4-(N,N-dimethylamino)phenyl group. © 2022, Ministarstvo Prosvete, Nauke i Tehnološkog Razvoja, MPNTR: 451–03–68/2022–14/200026, 451–03–68/2022–14/200135, 451–03–68/2022–14/200287, This work was supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (Contract No. 451–03–68/2022–14/200287, 451–03–68/2022–14/200135 and 451–03–68/2022–14/200026).

This paper proposes a novel hierarchical optimization framework that couples the balancing problem of a community network with building energy management (BEM) to form an integrated model capable of capturing potential joint-flexibilities of connected buildings while co-optimizing the operation schedules of community-operated assets. The proposed framework comprises a community-level power flow-based model to solve the energy procurement problem of the community and a building-level physics-aware simulation model to estimate a set of day-ahead aggregate load scenarios with potential joint-flexibilities. At the building-level, a least-cost multi-objective optimization provides a sequence of optimal temperature setpoints for all thermal zones that is fed into an accurate Gradient Boosting Machine (GBM) to estimate heating, ventilation, and air conditioning (HVAC) load trajectories while considering human comfort, occupancy patterns, building thermal response, and intraday electricity prices. The community-level model co-optimizes day-ahead schedules of shared distributed energy resources (DERs) and electric vehicle (EV) chargings while directing the building cluster to adapt the joint-flexibilities to balance the community network under different operation conditions. Finally, a test building cluster located in Qatar University is investigated through several case studies. The simulation results reveal the model’s practicality in fully capturing the joint-flexibilities of the building cluster for an adaptable community operation which cuts the operation cost by 21.04%. This work was partially supported by the Qatar National Research Fund (a member of the Qatar Foundation) through the National Priorities Research Program (NPRP) Award under Grant NPRP11S-1228-170142. The statements made herein are the sole responsibility of the authors. The APC was funded by the Qatar National Library .

Numerical simulations of photovoltaic solar panels are performed using temperature-dependent layer properties. The results are compared with experimental data recorded from a 50 W mono-crystalline panel and a 50 W poly-crystalline panel. The comparison shows that, for both panels, introducing temperature dependencies in the layer properties can significantly improve the accuracy of numerical simulations. On a sample day in August 2019, the mean absolute error in power prediction is found to decrease from 9.13 to 4.32% for the mono-crystalline panel and from 9.49 to 5.55% for the poly-crystalline panel, representing accuracy improvements of 52.7% and 41.5%, respectively. On an annual basis, the accuracy of estimating the power generated by the mono- and poly-crystalline panels improves by 52.8% and 41.4%, respectively. Finally, it is found that as the standard deviation of the temperature distribution on the panel increases, so does the effect of the temperature-dependent layer properties. This study highlights the need to account for the temperature dependencies of the different layer properties when numerically simulating photovoltaic panels.

Four novel alternating copolymers bearing 5-fluoro-6-((2-octyldodecyl)oxy)benzo[c][1,2,5]thiadiazole as a strong acceptor unit and 9,9-dioctylfluorene as a strong donor unit with bridging units namely, thienothiophene, selenophene, 3-hexylthiophene, and thiophene were designed and synthesized. The polymers were characterized via 1H NMR spectroscopy, and weight average molecular weights were reported via gel permeation chromatography (GPC). For synthesized novel polymers, the bulk heterojunction solar cells were constructed. Besides, the effects of bridging units on electronic, optical, photovoltaic, and morphological properties were investigated. Among the polymers, the thienothiophene containing polymer P1 exhibited the highest PCE as 4.25% under the illumination of AM 1.5 G with 100 mW/cm2.

We measure the three dimensional movement of cracked solar cell parts in standard sized PV-modules during a four line bending test. We develop a model which explains this movement assuming that the centers of mass of the solar cells or cell parts are fixed to the module glass. The widening of all cell gap widths is proportional to the bending roll displacement until a cell cracks in parallel to the bending rolls due to the tensile stress in the cells. At this point, the crack opens abruptly while the two parallel cell gaps next to the cracked cell close simultaneously by the same distance in sum. From here on, the cell gaps and the cell crack increases proportionally to the bending roll displacement. Since the distance between the centers of mass of both cracked cell parts is independent of the crack position, the crack width is also independent of the crack position for single cracks. Multiple parallel cracks in solar cells have smaller crack widths according to this model. Laminates without a backsheet show about 30% larger crack widths.

International audience; In this paper, a new approach to study the impact of the climate on the optimal sizing of a stand-alone PV/hydrogen/battery-based hybrid building is presented. A general method is described to evaluate the thermal need of the building, as well as the local photovoltaic resource, rather than using specific data available for large purpose applications. The proposed approach enables comparison studies between different places and climatic conditions. Considering a specific autonomous building, a comparative study is provided for different areas worldwide: Moscow, Cairo, Paris, Hanoi and Montreal. A Genetic Algorithm is used to provide an optimal size and energy capacity estimation for each location. The objective is to minimize the total cost while constraining the Loss of Power Supply Probability (LPSP) and the State of Charge (SoC) of the long-term storage element over one year. The sizing results between the different places demonstrate that the local climate has a huge impact on the final price, by highly modifying the PV resource and the thermal need of the building. The results demonstrate an 80% increase variation of the total installation cost between the area of Montreal and the one of Cairo.

The quartz tube solid particle air receiver is a new type of solar receiver in which fluidized particles absorb the solar radiation directly and heat the air effectively, improving the efficiency of solar thermal power generation and reducing costs. In this article, transient numerical simulation was conducted to simulate the heat transfer and flow processes in single quartz tube under concentrated solar radiation. The results showed that the distribution of solid particles temperature was uniform in the fluidized region, which could overcome the problem of overheating in the volumetric solar receiver. The temperature difference between solid particles and air was no more than 25K, indicating that heat transfer between particles and air was very effective. Further, as the direct solar radiation increased, the average air temperature in the outlet increased while the thermal efficiency decreased. The high tube wall temperature caused heat loss to the environment by radiative and convective heat transfer. With the air inlet velocity increasing, the averaging air temperature in the outlet decreased while the efficiency of the receiver increased. The simulation results provided important reference for improving the performance of the quartz tube solid particle air receiver.

Mixtures of straight and defect-free multiwalled carbon nanotubes (MWCNTs), single walled carbon nanohorns (SWCNHs), and multiwalled carbon nanohorns (MWCNHs) were prepared by the arc discharge method. Functionalized Carbon Nanotubes (FCNTs) composed of MWCNTs, MWCNHS and SWCNHs were obtained using acid functionalization process. TiO2/FCNTs (CTP) nanohybrid photocatalysts were obtained with different amounts of FCNTs (2-20 wt%), by wet impregnation method. The photocatalytic activity of both pristine TiO2 as well as the nanohybrids were studied in aqueous glycerol solution under solar irradiation. Reaction parameters such as amount of catalyst and amount of FCNTs in nanohybrids were optimized to ensure high rates of H2 production. With a relatively low amount of pristine TiO2, a high rate of H2 production of 2134 ?mol h-1 gcat -1 has been obtained and is likely due to several factors such as well dispersed catalyst, reduced particle-particle agglomeration, resulting in enhanced light absorption (less light shielding), improved separation of charge carriers and utilization for red-ox reactions. Even better results were obtained with the use of nanohybrid catalysts. The enhanced photocatalytic activities of the nanohybrid catalysts are ascribed to the synergetic effects of FCNTs that minimize light reflection which promotes enhanced solar light sensitization, good dispersion of the catalysts in the reaction solution, and improved surface-interface reactions of photogenerated charge carriers. In the present study 10 wt% FCNTs in nanohybrid (CTP-10) exhibited superior photocatalytic activity for H2 generation, nearly 3 times higher than that of pristine TiO2 catalyst. The CTP-10 photocatalyst exhibited photostability under the experimental conditions studied. The nanohybrid photocatalysts were characterized in order to confirm the crystal structure, morphology, surface chemical composition and optical properties. The present work demonstrates the unique beneficial photocatalytic properties of carbon nanotubes and nanohorn mixtures in nanohybrid photocatalysts, for enhanced H2 production. � 2014 Hydrogen Energy Publications, LLC.

The development of efficient solar receivers for different types of solar collectors such as point focusing, line focusing and external towers have received major attention in solar thermal power conversion process. The point focusing or parabolic concentrators need the receiver with internal cavity absorber and heat transfer system design with limited length and diameter. The line focusing collectors are not limited by its receiver length with respect to the trough. In this regard an experimental simulation was carried out to enhance the overall heat transfer coefficient by effective design of shell and helical tube heat exchanger using silver (Ag) Nano particles with water as Heat Transfer Fluid (HTF), which reduces the length of the receiver in point focusing collector. The line focusing collector was analysed by 3D numerical model with porous discs of top half, bottom half, combination of top & bottom half and full shape with silicon carbide ceramic foam as a material to evaluate the performance of the receiver to suit for line focusing collectors. The results obtained with porous disc are compared with plain tube line receiver.

Fabrication of interdigitated organic photovoltaic (OPV) devices commonly involves filling a nanostructured thin film using solution-based methods. In these cases, the sensitivity of the nanostructured films to the solvents used needs to be studied in order to optimize the interface. Here, we study the ability of chlorobenzene (CB) and dichlorobenzene (DCB) to dissolve and recrystallize zinc phthalocyanine (ZnPc) thin films, while fabricating interdigitated active layers composed of ZnPc and [6,6]-phenyl-C 61 butyric acid methyl ester (PCBM). Using glancing angle deposition (GLAD), we are able to construct slanted nanorod arrays of ZnPc, with nanorod diameters of nominally 40 nm and lengths up to 450 nm. We find that these films are recrystallized upon direct exposure to CB and DCB, regardless of initial morphology, yielding a variety of possible nanoscale formations. The crystallinity and absorbance of these recrystallized films changes as well, depending on solvent choice and exposure time. Through control of initial ZnPc film morphology and solvent choice for PCBM casting, we exploit the sensitivity of ZnPc to these organic solvents to optimize the photovoltaic performance of ZnPc/PCBM devices. Optimal OPV device performance is achieved with a 30 nm thick GLAD-textured ZnPc film while using DCB as the PCBM solvent. In this case, power conversion efficiencies are up to 3.0%, compared to an average of 2.3% when using CB as the solvent on the same film, and 2.3% also for bilayer devices when using DCB as the solvent. A higher degree of material mixing at the ZnPc/PCBM interface is shown when using DCB over CB as the PCBM solvent, which may be the primary mechanism for the photovoltaic improvements seen in these devices. © 2011 Elsevier B.V. All rights reserved.

Four europium complexes with enhanced luminescent properties have been synthesized. Thin transparent films of the complexes were prepared on glass panes and then were examined as efficient luminescent solar concentrators for full spectrum utilization in crystalline silicon photovoltaic cells. The complexes could behave as efficient solar concentrators since they absorb UV light, where the spectral response of the crystalline silicon solar cells is low and they emit at 615 nm where the spectral response is maximum. The glass panes covered with europium complexes act as planar waveguides of the emitted light that is collected by the solar cells, which are attached to the edges of the solar concentrators. The europium complexes as solar concentrators were examined in terms of the optimum concentrations and the number of coatings, which were determined in order to evaluate the maximum performance of the solar cells. The case of multiple glass panes with europium complexes was also examined while a 28% maximum increase in the photocurrent was finally established. © 2011 Elsevier B.V. 131 8 1776 1781

The effect of the molecular weight of poly[9,9-didecanefluorene-alt-(bis-thienylene) benzothiadiazole] (PF10TBT) on the photovoltaic performance of fullerene-based bulk heterojunction solar cells is investigated. An increase in molecular weight of two orders of magnitude results in a 30% increase of the short-circuit current and a rise of the fill factor from 0.45 to 0.63. Electron and hole transport are found to be virtually unaffected by changing molecular weight, which means that space-charge effects do not play a role in low molecular weight devices. Using optical modeling and numerical device simulations, we demonstrate that at low molecular weight the efficiency is mainly limited by a short lifetime of bound electron-hole pairs. This short lifetime prohibits efficient dissociation and is attributed to a deficiency in phase separation for low molecular weights. (C) 2009 Elsevier B.V. All rights reserved.

In this paper, energy and exergy analyses for a 1.2 kWp Nexa PEM fuel cell unit in a solar-based hydrogen production system is undertaken to investigate the performance of the system for different operating conditions using experimental setup and thermodynamic model. From the model results, it is found that there are reductions in energy and exergy efficiencies (about 14%) with increase in cur-rent density. These are consistent with the experimental data for the same operating conditions. A parametric study on the system and its parameters is undertaken to investigate the changes in the efficiencies for variations in temperature, pressure and anode stoichiometry. The energy and exergy efficiencies increase with pressure by 23% and 15%, respectively. No noticeable changes are observed in energy and exergy efficiencies with increase in temperature. The energy and exergy efficiencies decrease with increase in anode stoichiometry by 17% and 14%, respectively. These observations are reported for the given range of current density as 0.047-0.4 A/cm(2). The results and analyses show that the PEM fuel-cell system has lower exergy efficiencies than the corresponding energy efficiencies due to the irreversibilities that are not considered by energy analysis. In comparison with experimental data, the model is accurate in predicting the performance of the proposed fuel-cell system. The parametric and multivariable analyses show that the option of selecting appropriate set of conditions plays a significant role in improving performance of existing fuel-cell systems. (c) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.

This paper describes a system for the remote monitoring and control of complex stand-alone photovoltaic plants. In normal conditions, the system records and periodically reports the overall performances, whereas, in case of incorrect behaviors, it immediately informs the operators. Moreover, through appropriate instructions, users are able to modify some elements of the plant and the settings of the measurement system. In order to adapt the system to the specific operative conditions, several means of communications and plant configurations were investigated. However, for a more general, flexible and cost-effective implementation, the remote communications are based on the GSM network and, in particular, on the short text message service.