Applied Solar Energy最新文献

Solar drying is a method employed to expedite moisture reduction and enhance preservation capacity, characterized by intricate heat and mass transfer processes, challenging the micro-level description of drying kinetics. This study aims to optimize solar drying conditions for kola fish using a double slope solar dryer. An empirical investigation was conducted in three modes viz: open sun drying, natural convection solar dryer and forced convection solar drying. The research underscores the advantages of forced convection drying, showcasing a notable reduction of 4 h in drying time in comparison to natural convection. Furthermore, natural convection surpassed open sun drying, yielding an impressive 18-hour time-saving. An empirical model was formulated to establish the relationship between surface temperature and influential parameters, including insolation, air temperature, and ambient temperature. This model exhibited a high degree of reliability, featuring a correlation coefficient of 0.982 and a narrow standard deviation of 0.028, enabling precise surface temperature predictions under various conditions. The study delved into the effective moisture diffusivity range of kola fish, pinpointing it within the range of 5.16 × 10^–9 to 5.29 ×10^–8 m²/s. This understanding of intrinsic moisture migration during drying contributes to process optimization. Furthermore, the determination of the activation energy for kola fish drying, which ranged from 28.34 to 38.83 kJ/mol, elucidates the temperature-dependent nature of drying kinetics and underlying energy-driven mechanisms. These revelations significantly enhance the comprehension and advancement of controlled solar drying techniques for kola fish.

An insight analysis of In_0.7Ga_0.3N based pn homo-junction solar cell structure has been carried out using simulation software. A novel solar cell structure of n+ buffer contact layer/n window layer/p absorber layer/p+ back absorber layer has been proposed after device optimization. We have found that under the sun spectrum of AM 1.5 of 1 KW/m² operating at 300 K, the solar cell with low series resistance of 3 Ω cm², highly doped (1×10¹⁹ cm^–3) n+ layer as buffer contact layer and p+ layer of 200 nm thick as back absorber layer on top of back metal contact, enable us to achieve an efficient solar cell. We found that doping concentration of (1 times {{10}^{{16}}}{text{ c}}{{{text{m}}}^{{ - 3}}}) in both active n and p layer, with 30 nm and 1.0 ({{mu m}}) of thickness, respectively, would allow us to achieve short circuit current density of (35{{{text{ mA}}} mathord{left/ {vphantom {{{text{mA}}} {{text{c}}{{{text{m}}}^{2}}}}} right. kern-0em} {{text{c}}{{{text{m}}}^{2}}}}), open circuit voltage of 1.0 V, overall efficiency of 28.32% and fill factor value of 80% from the solar cell. If we could further reduce the series resistance of In_0.7Ga_0.3N pn homo-junction solar cell to ideal one, it may allow us to have even higher overall efficiency and fill factor values of 31 and 86%, respectively.

The aim of this work is to develop a neuro-fuzzy model (ANFIS) for the calculation of the open circuit voltage and the maximum power voltage of photovoltaic generators of four types of technologies. The technologies studied are amorphous/microcrystalline, cadmium telluride, copper indium di-selenium, and monocrystalline silicon. In order to evaluate the performance of the proposed ANFIS model, we compared the electrical characteristics determined using the ANFIS system to the electrical characteristics obtained using a system of analytical equations developed by smoothing the experimental measurements. For the experimental validation of our research work, we used an experimental database from the station located at Green Energie Park in Bengrire Morocco, The Green Energy Park is a solar energy test, research and training platform located in the green city of BenGuerir in Morocco. It was developed by the Institute for Research in Solar Energy and New Energies (IRESEN) with the support of the Ministry of Energy, Mines, Water and the Environment as well as the OCP Group. This first platform in Africa, a unique model of its kind, allows on the one hand, the creation of synergies and the pooling of research infrastructures to create a critical mass and achieve excellence, and on the other hand the acquisition of knowledge and know-how by the various partner universities as well as the industrialists. The comparison results show that the proposed ANFIS model is more accurate than the analytical model and allows to better emulate the electrical characteristics of the studied photovoltaic generators. The performance of the ANFIS model is evaluated using various performance metrics, such as mean absolute error, root mean squared error, and correlation coefficient. The results show that the proposed ANFIS model is capable of accurately predicting the open-circuit voltage and the maximum power voltage of the four PV technologies. The model can be used as an effective tool for designing and optimizing photovoltaic systems that incorporate these technologies.

The solar cell operating at a temperature of around 298 K gives superior performance compared to other temperature ranges. However, variation in sun insolation received due to season and latitude variation changes the temperature drastically, so the performance of solar cells also varies. If the temperature varies above a particular limit, it causes a negative effect on the performance parameters of solar cells. This is due to the fact that intrinsic carrier concentration, band gap E_g and dark saturation current I_o of semiconductor material silicon are highly dependent upon the temperature. Various performance parameters of Silicon solar cells, such as efficiency η, short-circuited current J_sc, open-circuited voltage V_oc, and fill factor FF, depend upon the temperature directly or indirectly. The effect of change in temperature beyond an optimum range, i.e., 300 to 400 K, on the performance of silicon-based solar cells under an AM1.5 spectrum is thoroughly and theoretically examined in the present paper. In this paper, the performance of silicon-based solar cells is examined and evaluated in a temperature range from 300 to 400 K. All these factors decrease with an increase in temperature.

Hydrogen energy is very promising nowadays due to no or very low carbon emission during energy conversion. Hydrogen as a fuel mainly caters in engines and fuel cells used in the automobile sector. Though there are issues regarding transportation and storage of H₂ but research and development is going on to improve such issues. Commercial vehicles are already in the streets worldwide powered by H₂. India is also not far behind. To develop the hydrogen economy throughout the country, India has launched the National Hydrogen Mission which focuses on generation of blue and green hydrogen. There are several ways to generate H₂ out of which electrolysis is one of the simple and clean technologies. H₂ generation through electrolysis is very much dependent on the ambient parameters. Tropical climatic regions have several weather seasons throughout the year which have direct impact on the H₂ generation through electrolysis. In this study, a simulation has been carried out for green H₂ generation with a PV powered electrolyzer with the help of MATL-AB Simulink simscape module by taking all the ambient parameters of a tropical region in India and the effect of seasonal variation on H₂ generation has been evaluated. It has been observed that due to changes in ambient conditions monthly electrolyzer efficiency varies from 59.11% for the month of July to 66.06% for the month of March on and overall system efficiency on monthly basis with PV Module-DC/DC Converter-Electrolyzer varies from 9.8 to 10.4%.

The increasing food demand, decreasing fossil fuels, expanding population and degrading environment are the drivers leading towards development in sustainable processing and storage of agricultural products. The lack of agro production and the wastage in post-processing has pulled the eyes towards sustainable storage solutions. Drying is an ancient process used to remove moisture from the harvested products. Several researchers have performed various experiments to intervene in new technology in the field of drying. The aims are to review the recent development occurring in drying technology. Waste energy recovery system coupled with solar dryer shows very good potential, while its application is more complex than solar drying. Hybrid system focuses on reducing the time of drying. The secondary source of heat was either an LPG heater or an electric heater, but its availability around various regions is still a challenge. Phase change material in solar drying technology can provide a desirable solution to post-harvesting problems. Currently the use of solar thermal energy into industrial drying processes is just to improve efficiency, reduce energy consumption, and lessen environmental impact. Economic aspects of the solar drying technology is very important for implementation of the systems. This article will help the policymaker and the researchers to make framework for energy policies in future.

The heliostat field is an important subsystem of the tower CSP station. The optimal layout of the heliostat field is one of the key issues to be solved in the early stage of the tower CSP station construction. Comprehensive efficiency of the heliostat field directly determines the highest performance of the power generation system. After analyzing the optical efficiency composition, optical efficiency distribution and related layout methods of the heliostat field, the goal is to have the highest annual average optical efficiency of the heliostat field. A dense simulated heliostat field with 2640 heliostats is established by the radial grid method. After selecting the appropriate heliostat field parameters, the cosine efficiency, shadow and block efficiency, atmospheric attenuation efficiency and comprehensive efficiency at different time points in the heliostat field are affected. In the optimization process, different search strategies are automatically selected, which improves the solving ability of the algorithm. Based on the Campo layout method, a new heliostat field layout method is proposed combined with the Adaptive Gravity Search Algorithm. The layout process starts from a dense heliostat field that is 1.5 times larger than the target heliostat field. The radius of the ring where the heliostat is located is used as the input variable and the annual average efficiency is used as the evaluation standard for the optimal layout of the heliostat field. After setting the corresponding constraints, the Adaptive Gravity Search Algorithm is used to find the best line spacing combination until the energy gain of the heliostat field reaches the maximum. Then, according to the design requirements, the inefficient heliostats are eliminated to obtain the final heliostat field arrangement. Finally, the heliostat field of the Gemasolar tower solar thermal power station in Seville is taken as an example to verify the method and prove the feasibility of the method.

The solar air heaters fabricated from plastics could reduce both material and fabrication costs. However, those fabricated from conventional plastics such as PVC suffer from the fundamental drawback that they cannot withstand higher temperatures. This work aims at fabricating a plastic solar air heater (PSAH) using chlorinated poly vinyl chloride (CPVC) and experimentally investigating its performance with cover made of 0.5 mm thick polyethylene and that without cover. To examine the effectiveness of PSAH at a tilt angle of 30°, all investigations were carried out at the University campus of Manipal, Dubai (25°08′00.1″ 55°25′31.0″ E) at an average global solar irradiation of 290 W/m²and average ambient temperature of 33–37.7°C from April16 to May 20, independently, for the two situations: with and without covers. The temperature rise of the air was recorded in both the inlet and outflow at different intervals by adjusting the MFRs of the air in steps of 0.025 kg/s, ranging from 0.02 to 0.055 kg/s. Energy efficiency (η_energy), exergy efficiency (η_exergy) of the collector, coefficient of hydraulic resistance, pressure drop, heat loss factor and thermal and optical heat losses were evaluated at various mass flow rates (MFR) of air as well as with the time of the day. It was found that the highest collector’s η_energy is found as 30 and 70.6% respectively for PSAH without cover and with cover with a constant inflow of air at 0.05 kg/s while the highest η_exergy is observed to be 17.8 and 26.1% respectively at an MFR of 0.03 kg/s. Collector’s η_energy increases with an increase in MFR of air while η_exergy shows the reverse trend. The highest rise in temperature of air was found to be 14.5 and 44^oC for PSAH without and with covers respectively. The coefficient of hydraulic resistance and pressure drop were observed to be insignificant. The overall heat loss coefficient for convection is calculated for PSAH without and with top covers respectively to be 3.7 and 2.4 W/m² K. The maximum rates of thermal and optical losses were also calculated for PSAH without and with top covers to be 140, 75 W and 102 and 42 W respectively. Thus, the useful energy without and with top covers is 38 and 59% respectively of the total energy supplied by the PSAH (345 W).

Sb_xSe_y thin-films were deposited by chemical-molecular beam deposition (CMBD) on soda-lime glass from antimony (Sb) and selenium (Se) precursors. Due to the separate control of Sb (between 980 and 1025°C) and Se (between 415 and 470°C) source temperature, thin films of antimony selenide with different component ratios carry out obtained. The investigation encompassed a comprehensive analysis of the elemental and phase composition, like the crystal structure, of Sb_xSe_y films. To achieve this, a combination of analytical techniques was employed, including energy-dispersive X-ray microanalysis, atomic force microscopy, Raman spectroscopy, X-ray diffraction, and scanning electron microscopy. The bandgap of the films was ascertained in the region 1.03–1.25 eV through the acquisition of absorption spectra using a spectrophotometer. This enabled the determination of the films’ optical properties and facilitated further analysis of their potential applications. The physical properties of Sb_xSe_y films with various ratio were researched.

The paper presents the results of experiments with a solar greenhouse used to ensure the most favorable temperature regime. In order to provide thermal insulation and reduce heat losses, a solar greenhouse structure with an arched shape and a total area of 200 m² has been developed. It is located directly in the ground, at a depth of 0.5 m and a height of 4.0 m above ground. The total height of the greenhouse is 4.5 m, the length is 20 m, and the width is 10 m. These dimensions comply with the standards established in KMK 2.09.08-97 Greenhouses and Hotbeds. On the outer part of the solar greenhouse, a layer of dry straw with sufficient permeability to sunlight is placed between two transparent enclosures during the winter period for thermal insulation. This significantly reduces heat losses through the top transparent surface and enhances the greenhouse effect. This transparent enclosure design allows heavy mechanical loads, is resistant to mechanical cleaning processes, and at the same time, has high thermal insulation properties. By using the solar greenhouse structure with the energy flow scheme presented, a more homogeneous air environment with temperature inside the greenhouse can be achieved, even during daily fluctuations in the temperature of the surrounding air. The temperature and humidity parameters inside the solar greenhouse vary due to the absorption of solar radiation from the ground surface and the evaporation of moisture from the soil. The results of the experiments show that the solar greenhouse based on our energy flow scheme, using the ground as thermal insulation, significantly reduces heat losses through the floor. The method of insulation between two transparent enclosures provides a more homogeneous air environment with air temperature inside the greenhouse, despite significant daily fluctuations in the temperature of the surrounding air, and effective accumulation of solar energy inside the solar greenhouse.