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Uncertain Analysis of a Stationary Solar Compound Parabolic Concentrator PV Collector System Using Fuzzy Set Theory
摘要： The uncertain analysis of fixed solar compound parabolic concentrator (CPC) collector system is investigated for use in combination with solar PV cells. Within solar CPC PV collector systems, any radiation within the collector acceptance angle enters through the aperture and finds its way to the absorber surface by multiple internal reflections. It is essential that the design of any solar collector aims to maximize PV performance since this will elicit a higher collection of solar radiation. In order to analyze uncertainty of the solar CPC collector system in the optimization problem formulation, three objectives are outlined. Seasonal demands are considered for maximizing two of these objectives, the annual average incident solar energy and the lowest month incident solar energy during winter; the lowest cost of the CPC collector system is approached as a third objective. This study investigates uncertain analysis of a solar CPC PV collector system using fuzzy set theory. The fuzzy analysis methodology is suitable for ambiguous problems to predict variations. Uncertain parameters are treated as random variables or uncertain inputs to predict performance. The fuzzy membership functions are used for modeling uncertain or imprecise design parameters of a solar PV collector system. Triangular membership functions are used to represent the uncertain parameters as fuzzy quantities. A fuzzy set analysis methodology is used for analyzing the three objective constrained optimization problems.
关键词： uncertain analysis,solar CPC PV collector system,fuzzy set theory,solar energy,optimization
更新于2025-09-04 15:30:14
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Solar-charged pseudocapacitors: Simultaneous conversion and storage of solar energy in ZnO@NiO nanorod arrays
摘要： In this paper, bias-free solar-driven pseudocapacitors based on ZnO@NiO nanorod arrays had been reported, which enable the synergistic coupling of light harvesting and electrochemical storage within one single electrode. When solar-charging, ZnO/NiO PN junction served as a driving force to separate the excitons and induce electron-injection through the interface to counter electrode forming charging bias. At this bias, the OH- trapped by photoexcited holes can make redox reaction with NiO and produce electrons. As expected, under a 1-sun illumination and no external electric bias, this ZnO/NiO composite exhibits a good specific capacitance of 44.5 F g?1 at current densities of 0.5 A g?1 as well as a good cycling performance (99% capacity retention after 50 cycles). Additionally, the capacitance equation was derived to account for the boosted capacitance as the increased solar-charging time. These findings here suggest the potential of further developing light-induced electrical energy storage and release on demand by a one-component light-charged capacitors.
关键词： solar energy conversion,ZnO@NiO nanorod arrays,photo-capacitor,pseudocapacitance
更新于2025-09-04 15:30:14
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Deploying enclosed trough for thermal EOR at commercial scale
摘要： Solar energy, in the form of enclosed trough direct steam generation, is now being deployed at scale to supply a portion of the energy demand for thermal enhanced oil recovery in Amal, Oman. Construction of the 1,021 MW Miraah project is well along and progress in cost reduction and labor productivity are evaluated. Results from the successful Manufacturing Verification Test and the Miraah Solar Steam Generator Project are presented and discussed. The Miraah data shows substantial reductions in material usage as a result of improved designs, increases in construction speed, and reductions in labor per unit of construction with deployment of enhanced tooling.
关键词： labor productivity,enclosed trough,thermal enhanced oil recovery,cost reduction,solar energy,direct steam generation
更新于2025-09-04 15:30:14
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Synthesis of novel form-stable composite phase change materials with modified graphene aerogel for solar energy conversion and storage
摘要： In this study, novel kinds of form-stable composite phase change materials (FS-CPCM) were prepared by the vacuum impregnation method. In the FS-CPCM, lauric acid (LA) was the PCM, and LA was grafted on the surface of graphene aerogel (GA) by an esteri?cation reaction and reduction process to prepare supporting material and increase the thermal conductivity of the FS-CPCMs. The microstructure, thermal storage properties, thermal conductivity and light-to-heat conversion of the FS-CPCMs were investigated. Scanning electron microscopy and Fourier transform infrared spectroscopy were used to demonstrate that the LA was encapsulated e?ectively in the porous structure of the LA-GA, and the LA/LA-GA FS-CPCMs were prepared successfully. X–ray di?ractometer results con?rmed that the crystallization of the LA/LA-GA FS-CPCM was better than that of LA/GA FS-CPCM. Thermal conductivity analyses indicated that the thermal conductivities of the LA/LA-GA-1 FS-CPCMs increased 352.1% and 32.6% compared with the conductivities of LA and LA/GA FS-CPCM, respectively. Di?erential scanning calorimetry results con?rmed that the LA/LA-GA-1 FS-CPCM possess good phase change behavior, low undercooling and excellent thermal cycling stability. The melting enthalpy and freezing enthalpy could reach 207.3 J/g and 205.8 J/g, respectively, and the LA/LA-GA FS-CPCM exhibited good thermal reliability and stability. Furthermore, the LA/LA-GA FS-CPCM had excellent photon absorption and the highest e?ciency in terms of light-to-heat conversion of 80.6%. Such good performances demonstrate the LA/LA-GA FS-CPCM's potential for use in solar energy storage systems.
关键词： Phase change materials,Thermal conductivity,Graphene aerogel,Solar energy conversion
更新于2025-09-04 15:30:14
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The reliability of solar energy generating system with inverters in series under common cause failure
摘要： With the shortage of nonrenewable energy, renewable energy resources play an important role in practice. One of the most promising renewable energy is viewed as solar energy resources due to its cleanliness and the inexhaustibility. However, the quantitative assessment method on the reliability of a complicated solar energy generating system has been a considerable challenge. In this paper, we propose a Markov model to imitate a solar energy generating system with inverters in series, unreliable by-pass change-over switches, and common cause failure. Employing the renewal point technique and the Semi-Markov process theory, we build the quantitative reliability models of the system. Further, we develop a new algorithm to obtain the explicit form solution of reliability indices. An example illustrates that the proposed models and the algorithm are e?cient and concise.
关键词： Common cause failure,Switch failure,Micro-inverters,Reliability,Solar energy generating system
更新于2025-09-04 15:30:14
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Hybrid global maximum power point tracking algorithm under partial shading condition
摘要： This paper presents a hybrid global maximum power point tracking (MPPT) algorithm under partial shading conditions, which consists of five methods, including the global scanning method, the filtering method, the binary searching method, the three-point method, and the anti-restarting method. By making full use of the advantages of these methods, the proposed algorithm is able to improve tracking speed and efficiency, decrease oscillation, and avoid restarting. Among which, the global scanning method is used to find all the local intervals, the filtering method is used to reduce the search area, the binary searching method is used to reduce the search time, the three-point method is used to track the global maximum power point dynamically, and the anti-restarting method is used to prevent restarting the algorithm. To verify the proposed algorithm, experiments have been carried out in a standard environment, dynamic solar irradiation, and dynamic temperature, respectively. The performance of the proposed algorithm is verified by comparing it with a perturb and observe (P&O) based global scanning MPPT method and a modified P&O with checking MPPT method using computer simulations.
关键词： MPPT,global maximum power point tracking,photovoltaic systems,partial shading condition,hybrid algorithm,solar energy
更新于2025-09-04 15:30:14
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[IEEE 2017 International Renewable and Sustainable Energy Conference (IRSEC) - Tangier (2017.12.4-2017.12.7)] 2017 International Renewable and Sustainable Energy Conference (IRSEC) - Solar PV Implementation in Industrial Buildings: Economic Study
摘要： Solar PV has seen exponential growth in the past few years among other renewable energy sources owing to major cost reduction and simpler implementation as rooftop installation. Based on the global trends, among all the end use categories industrial sector consumes the highest amount of energy. To achieve sustainable development, it is necessary to reform this sector. The combination of rooftop solar PV and industrial infrastructure seems to be a promising option. Industrial buildings have large roof areas, low shading effect, and at substantial power consumption make it best suitable for solar PV. In this work, a case study implementation of solar PV in midsize factory located in UAE is carried out. Five different scenarios are considered from which three are focused on technicalities (tracking, non-tracking, and storage) and two on the business finance (100% debt vs. 50% debt). Payback through electricity rate compensation is studied. It is seen that the best scenario in terms of technical configuration is a system with solar tracking and as far as financing the scenario with 50% debt.
关键词： Photo voltaics,economic study,Solar energy,sustainability
更新于2025-09-04 15:30:14
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Comparative investigation on the exergoeconomic analysis of solar-driven ejector refrigeration systems
摘要： In this article, the economic performance of the solar-driven steam ejector refrigeration system is addressed due to the rising beneficial adoption of this system with regard to using low-grade heat sources. For this purpose, a detailed exergoeconomic analysis on four proposed configurations of this system integrated with precoolers and/or preheaters is performed. At a refrigerant load of 5 kW, the results of this analysis show that it is more advantageous for all configurations to have evaporators work at 278 K with condensers remain at 311 K, whilst the generators are kept working at 362 K. The characteristics of each configuration are comprehensively discussed and compared. Based on the assessment of economic parameters, the fourth configuration provides the highest exergetic efficiency and the lowest total investment cost (0.1891 $/h) compared to the other configurations. The current work furnishes essential information that paves the way for future exergoeconomic studies in this field.
关键词： Solar energy,Exergoeconomic analysis,Ejector refrigeration system,Exergy
更新于2025-09-04 15:30:14
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Direct storage of holes in ultrathin Ni(OH) <sub/>2</sub> on Fe <sub/>2</sub> O <sub/>3</sub> photoelectrodes for integrated solar charging battery-type supercapacitors
摘要： Energy storage is a very significant issue for utilization of solar energy due to its discontinuous and unstable energy flux. Herein, for the first time, we propose a Fe2O3@Ni(OH)2 core–shell nanorod array as a photoelectrochemical battery-type supercapacitor for the direct storage of solar energy. Under light illumination, Fe2O3 absorbs solar energy and produces electron–hole pairs, while Ni(OH)2 stores the photo-generated holes, which can be released as electricity when the light is switched off. In addition, by controlling the valence band position of the semiconductor and the thickness of Ni(OH)2, the side reaction of water oxidation (electrolyte decomposition), which is harmful for the applications of a photoelectrochemical supercapacitor, can be completely suppressed. As a consequence, the specific capacitance of the Fe2O3@Ni(OH)2 photoelectrochemical supercapacitor is enhanced up to 20.6 mF cm?2 at a discharge current density of 0.1 mA cm?2, which is about 4.5 times that of BiVO4/PbOx reported in a previous study. This study offers a very promising device for the direct storage of solar energy and deepens our understanding on the interface charge transfer between a photoelectrode and a battery-type capacitive material.
关键词： water oxidation suppression,Fe2O3@Ni(OH)2,photoelectrochemical supercapacitor,core–shell nanorod array,solar energy storage
更新于2025-09-04 15:30:14
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Photo-Electrochemical Investigation of Inorganic/Organic Interfaces Assembly Consisting of Zn-Doped WO3 /Poly 4-(Thiophen-3-yl) Aniline
摘要： inorganic/Organic/Interfaces (IOI) consisting of Zn-doped WO3 (Zn-WO3) Photoactivities at /Poly 4-(Thiophen-3-yl) aniline (P3ThA) assemblies were investigated in nanoparticle suspensions and in thin solid film forms. The effects of P3ThA modifier on the photoelectrochemical behavior of the IOI were investigated using [Fe(CN)6]4- as a photoactive donor of hydrated electrons. Results show that the adsorption process of [Fe(CN)6]3- (photolysis product) controls the photoactivity outcomes of the IOI assemblies. P3ThA shows a greater heterogeneous photochemical response than native Zn-WO3. The band alignment between Zn-WO3 and P3ThA is of a p-p junction straddling gap type, where the charge transfer process is achieved through a hole transfer mechanism. The interface activities were explained by analyzing the IOI junction characteristics such as electron affinity, work function and hole/electron barrier heights. The creation of hybrid sub-band states close to the Fermi energy level at the interface was suggested. The aqueous nano-systems retained moderate stability as indicated by the reproducibility of their photocatalytic activities. Both [Fe(CN)6]4- and P3ThA contributed to the stability of the native Zn-WO3 surfaces.
关键词： photoelectrochemistry,solar energy,heterojunctions,semiconductors
更新于2025-09-04 15:30:14