Applied Solar Energy最新文献

SOEC (Solid Oxide Electrolysis Cell) require high temperature steam, but generating steam with electricity is very energy intensive. Concentrated solar power can be a good substitute for electricity to generate high temperature steam. In this paper, the thermal performance of a solar steam generator is researched. The steam generator improves the heat transfer capacity by installing porous ceramic material inside and using spray cooling technique. Due to the limited heat transfer capacity of previous steam generators, other types of steam generators can only produce steam with a temperature below 700°C. The steam generator in this paper has a high thermal efficiency depending on the nozzle characteristics. Therefore, the steam generator has obvious advantages in terms of generating high-temperature steam. The experimental results show that the instantaneous thermal efficiency of the steam generator with a new nozzle can reach a maximum of 58% when the solar irradiation power is 2.26 kW and the inlet water flow rate is 1.23 kg/h. At this time, the steam generator can produce high temperature water vapour at a maximum temperature of 715.4°C. The optimized solar steam generator was also coupled with the SOEC system, and hydrogen production was successfully achieved by experimental means. The solar SOEC system has great potential for hydrogen production.

The article proposes a technological scheme of a heliopyrolysis plant with a parabolic solar energy concentrator and presents the results of a study of the thermal technological regime of the process of pyrolysis of sunflower waste. To study the process, an experimental heliopyrolysis installation with a parabolic solar concentrator was created. The purpose of this work is to evaluate the practical possibility of solar technology for the thermal processing of sunflower waste using a parabolic solar concentrator and to determine the main parameters of the thermal technological regime of heliopyrolysis. The results of experimental studies of the process of heliopyrolysis of sunflower waste at a temperature of 400–500°C are presented. The values of the heat of combustion of liquid and gaseous biofuels obtained by solar pyrolysis were determined. It has been established that the value of the lower calorific value of liquid pyrolysis fuel is 35–40 MJ/kg, and the calorific value of gaseous fuel is 25–28 MJ/m³. During the experiments, the temperature dependence and material balance of the resulting products during the thermal processing of sunflower waste using concentrated solar thermal energy were studied. In experiments carried out at the installation, as a result of the pyrolysis of 1 kg of sunflower waste loaded into the reactor of a heliopyrolysis installation, 63% of biochar, 10% of liquid, and 27% of gaseous biofuels were obtained. The results of the studies showed that the yield of liquid pyrolysis products is affected by the humidity of the initial biomass; and the maximum yield of the liquid pyrolysis, and product of sunflower waste corresponds to a temperature of about 430°C and a humidity of the loaded initial biomass of 25%. Based on the conducted research, the effectiveness and possibility of using a heliopyrolysis installation with a solar parabolic concentrator to maintain the required temperature regime for the pyrolysis of sunflower waste in the daytime operating mode of the installation was substantiated.

Limited access to potable water sources is turned to one of the basic human concerns today. Therefore, solar desalination units as a cost-efficient solution have attracted more attention in recent years. Solar stills are devices of great interest to researchers because of the low cost of construction, having no complex mechanisms, and less need for service and maintenance. Much study has been recently done in relation to modeling, economization, and optimization of these devices, most of which were carried out in Asian countries with hot and dry climates. Regarding that solar desalination systems often enjoy low efficiency; the present work has reviewed researches conducted by others to evaluate the effect of magnetic impact using ({text{F}}{{{text{e}}}_{3}}{{{text{O}}}_{4}}) Ferrofluid and also ultrasonic waves as known approaches to enhance the performance and water output of such devices. The method and findings of the previous scientific studies are discussed comprehensively in this review.

Electrodeposition of CZT thin films can be a cost-effective and time-efficient process in obtaining CZTS absorber layer to be used in thin film solar cells. The electrodeposited film is composed of atomically mixed elements in different phases involving Cu, Zn and Sn which change significantly over a period of time. The films are characterized using XRD for probing phase evolution and to understand the time required to obtain stable phases. Soft annealing (250 and 350°C) of these films yielded stable phases that would otherwise take longer time intervals when stored at room temperature. Soft annealing followed by sulphurization yielded CZTS thin film with desired properties to be used as absorber material in thin film solar cells.

In order to increase the efficiency of solar air collectors, a type of solar air collector with hemispherical protrusions is proposed in this paper, and its performance is analyzed from two aspects of numerical simulation and experimental study. And the mathematical model of the collector is established and simulated with MATLAB program. By comparing the experimental data with the simulation results, the simulation can accurately predict the performance of the solar air collector. Considering some uncertainties in the input parameter values, the maximum difference between the predicted and the experimental results is about 10.6%, which is within an acceptable comparison range.

Uniform side-pumping can reduce the thermal stress of laser crystal rod and is an effective method to achieve high power laser output. In order to realize the uniform side-pumping of the laser crystal rod, a solar concentrating system based on plane mirrors and linear Fresnel lens array is proposed. Rays tracing shows that the concentrating efficiency of solar concentrating system and the uniformity of the light spot reach 66.5 and 98.5% with optimization. The temperature distribution in the laser crystal rod is calculated by Comsol software. The results show the central temperature and the surface temperature of laser rod are 316 and 306 K, respectively. Base on solving the rate equations, the laser output characteristics are analyzed. The laser output power and the solar-to-laser conversion efficiency are 88.5 W and 3.3%, respectively. This uniform side-pumping configuration provides the new method for developing high power solar-pumped solid-state lasers.

The densities and fluxes of concentrated solar radiation in the focal plane of large solar furnaces (LSFs) are studied, taking into account the overall parameters, inaccuracies in the facets of the concentrator and heliostats, and shading and blocking the sun’s rays by the fields of heliostats. It was found that LSFs can work effectively for 8 h a day throughout the year. It is shown that when the irradiance in the focus of the LSF is 0.6 from the limit, the root mean square error (RMS) of angular inaccuracies σ can be about 7 ang. min, and, if they are equal, each flat component (there are eight of them) can have deviations up to ±4.2 ang. min, which if within σ, can be redistributed. The negative constant component of the inaccuracies of the curvature radius (integral inaccuracy) of the facet concentrator has a strong influence on the irradiance in the focus of the LSF, it should not be less than –0.2.

Heliostats are integral components of tower solar thermal power generation systems, optimizing heliostat efficiency directly impacts overall power generation effectiveness. This research focuses on evaluating and enhancing heliostat optical quality and tracking accuracy, critical factors influencing their concentration efficiency. The study presents a comprehensive approach based on spot evaluation and correction techniques to assess and boost heliostat performance. Static Optical Quality Assessment, A novel methodology is introduced to appraise heliostat optical quality. It involves capturing heliostat spot shapes through image processing, followed by fitting and comparison with theoretical simulations. This technique provides valuable insights into heliostat mirror quality. Dynamic Tracking Accuracy Evaluation scheme is devised to evaluate dynamic tracking accuracy, by analyzing centroid positions of spots captured at regular intervals, horizontal and vertical tracking deviation angles are computed. These angles gauge heliostat dynamic tracking accuracy. To refine dynamic tracking accuracy, a heliostat tracking error correction scheme is proposed. A dynamic geometric tracking error model is formulated, enabling the derivation of a precise tracking angle calculation formula. A least squares mathematical model is established to solve for unknown tracking errors, facilitating accurate error angle calculation and subsequent correction. The presented static spot quality and dynamic tracking accuracy evaluation methods offer simplicity, precision, and efficiency. These techniques hold practical significance for tower solar thermal power generation systems. The devised tracking error correction scheme demonstrates practical effectiveness, validated through experimental simulations and real-world measurements. Implementation of this scheme substantially enhances concentrating power generation efficiency within tower solar thermal power generation systems.

This paper presents a validation of a proposal combined analytical and numerical approach applied to a single diode model of photovoltaic (PV) module for extracting its five PV parameters: shunt resistance, series resistance, diode ideality factor, photo-generated current and saturation current. This method is tested using data provided by manufacturer’s datasheets for three PV panels technologies: multicrystalline Kyocera (KC175GHT-2), monocrystalline Silicon Shell (SQ-150PC) and heterojunction with amorphous silicon “intrinsic thin-layer” “HIT-240HDE4” under variable environmental conditions. The simulation results in MATLAB environment show a good agreement between simulated and experimental power-voltage and current-voltage characteristics for different irradiation levels and temperature values. This accuracy of the proposed method has been confirmed by lowest root mean square error (RMSE) whatever the weather conditions compared to recent conventional approaches reported in the literature. Furthermore, this new approach is tested experimentally on three types of photovoltaic modules’ data provided by “NREL”: The National Renewable Energy Laboratory, USA. An accurate knowledge of photovoltaic panel parameters from measurement data is essential for solar panels quality control, design and estimating their performance. Indeed, the photovoltaic panel is prone to degrading over time owing to aging and weather exposure. Therefore, predicting these performance degradations is key to avoid their negative impacts on PV production. For this purpose, this work presents a fast, simple, and precise approach of PV parameters extraction to obtain an exact model which more accurately emulates the photovoltaic modules characteristics under a large interval of temperature and irradiation levels, and valid for different PV technologies. Also, from the performance comparison of these three PV panel technologies, we have concluded that the monocrystalline module shows the best performance on the Cocoa, Florida (subtropical climate) with an average performance ratio of 100%.

The one-dimensional software known as solar cell capacitance simulator, commonly called as SCAPS-1D, has been used to study the transition metal dichalcogenide WS₂/CdS/ZnO:Al solar cell with WS₂ as the absorber layer material. Variations in thickness, ambient temperature, density of defects, and defect charge states have been used to study the photovoltaic performance parameters. So as to achieve increased efficiency, it was shown that the defect concentration in the light absorbing layer needs to be decreased to the lowest achievable values. Additionally, it has been found that the characteristics showing the performance of the solar cells are significantly influenced by the charge type of the defects.