Applied Solar Energy最新文献

The current state of affairs on the Photovoltaic emulator (PVE) is facing two main challenges: complexity in resolving the nonlinear equations of the photovoltaic (PV) and the problem of effective control of the PVE power conversion stage (PCS). In this paper, a new power electronics-based PVE is proposed to emulate the dynamic and static characteristics of the PV cell/module. The nonlinear equations of the PV cell/module are resolved using a new piecewise segmentation technique, involving the splitting of the current-voltage (I–V) curve into twelve linear segments associated with the letters a to m (a–m). Based on input environmental conditions, a trained artificial neural network (ANN) is constructed to assist the linearization process by predicting the current-voltage boundary coordinates of these segments. By the use of simple linear equations with the boundary coordinates, a reference voltage is then generated for the PVE. A nonlinear backstepping controller is designed to exploit the PVE reference voltage and stabilize the PCS. The stability of the controller is verified by Lyapunov laws. Optimal performance and control of the PCS were ensured by resorting to particle swarm optimization (PSO). The overall system has been investigated in the MATLAB environment with major tests including the response to fast-changing irradiance and temperature, the EN 50530 test, and the response to change in the load. The proposed PVE revealed a satisfactory dynamic performances in mimicking the PV characteristics. Furthermore, the accuracy of the PVE as a function of the mean absolute percentage error (MAPE) was found less than 0.5% even for the worst case of environmental conditions. Experimental validation of the proposed PVE under real environmental conditions further validated its good dynamic and static robustness.

This study considers the process of accumulating electrical energy in autonomous mobile photothermal water-release devices (AMPTWDs) and autonomous mobile photovoltaic water-release devices (AMPVWDs). These devices are based on photovoltaic (PVB) and photothermal batteries (PTB), and their performance is examined in relation to variations in battery charge and device efficiency. The study investigates the operating time of PVB and PTB water-release systems with power outputs of 150 and 300 W, respectively. These systems are equipped with acid batteries (ABs) having an electrical capacity of 100 A h. Additionally, the study analyzes the AB charging process and water release efficiency. The experiment took place in June 2022 in the settlement of Beshbulok, situated in the Dehkanabad district of the Kashkadarya region at a geographical latitude of 38°20′51″. Prior to the experiment, the AB was charged to 100% over a 12-h period using a special charging device, and the voltage was adjusted to 12.7 V. The efficiency analysis of PTB and PVB-based water-release systems revealed that the AMPTWD based on PTBs generates 1.62 times more water than the AMPVWD based on PVBs. Furthermore, by using two gel ABs with a capacity of 100 A h each instead of the ABs installed in the AMPTWD based on 300 W PTBs, an additional 750 W of power was generated, independent of the power required for water release. It was determined that the water pump used in this experiment or other household devices with similar power demands could be supplied with energy for a duration of 3 h.

Due to the geographical location and natural climatic conditions, solar energy has a priority in Kazakhstan among all renewable energy sources. Some regions of Kazakhstan experience more than 270–300 sunny days per year, making it possible to utilize solar energy almost all year round. In this regard, there is a need for the development and implementation of large-scale solar technology. In this study, a comprehensive review and analysis of modern solar technology structures were conducted. The primary focus of this research lies in the following tasks: developing operational modes through computer simulation, modeling the structure of the focal spot in the optical system, and exploring the potential of employing contemporary digital and computer technologies. The optimization issues and computer simulation of the operating modes of the optical system in a tower-type solar power plant are considered in more detail. A calculation scheme and a mathematical model have been developed to estimate the local values of the efficiency coefficient (η) for the use of a mirror surface of the heliostat field. The results are visually presented in the form of a map for local values of the efficiency coefficient (η) of using the mirror surface of the heliostat field in tower-type solar power plants.

This work investigates the issues found in the dynamic performance of the PV system associated with a cascade-controlled DC-DC converter in the current source region (CSR). The overall system time response in the CSR exhibits oscillatory behavior which has been found to be caused by the outer voltage control loop. Instead of a commonly used tracking controller, a novel disturbance rejection-based cascade controller is proposed in order to improve dynamic system performance and robustness. The proposed controller is composed of a sliding mode controller for the inner current control loop and a feedback linearization combined with the fractional order PID controller for the outer voltage control loop. The voltage controller is tuned using the Equilibrium Optimizer (EO) algorithm where a new performance index has been considered. Simulation results are given to demonstrate the higher performance of the proposed control strategy in different operating regions including the CSR region.

Since the beginning of the third millennium, significant growth in the usage of conventional air conditioning systems was observed. This increase caused an enhancement in building electricity consumption. Therefore, the development of solar air conditioning systems applied to buildings is of great interest. However, it is essential to understand and assess this alternative solution. In this regard, this study focuses on solar cooling technology as an alternative to conventional air conditioning systems, which consume a significant amount of electricity. A mathematical model of a single-effect absorption chiller was developed using TRNSYS software to analyze the dynamic behavior of the system. The energy performance of the solar cooling system was evaluated by analyzing the solar fraction, coefficient of performance, and thermal efficiency. The optimal size of the solar panel surface and storage reservoir capacity were determined for Oujda, Morocco’s climatic conditions. Simulation results showed that a 600 m² flat plate collectors (FPC) with a 2.5 m³ storage tank could sustain a peak load of 108 kW while ensuring continuous performance. The system’s efficiency was improved by maximizing useful energy and minimizing supplementary energy consumption, achieving a significant monthly average solar fraction in July to meet cooling demand. The coefficient of performance of the absorption chiller was found to be 0.53, maintaining a chilled temperature of 6.67°C. These findings demonstrate the potential of solar cooling technology as an effective and sustainable alternative for building air conditioning.

A compressor is the most power-consuming component in a refrigeration system, and energy scarcity in the form of electricity has become a grave challenge in today’s world. Replacing the compressor with solar-powered clean energy could be an efficient alternative to reduce energy consumption significantly. The system presented comprises a Solar-powered Thermal Refrigeration System based on the Peltier Effect, functioning on a cooling module. Since the system is solar-powered, an automatic solar tracker that incorporates Light Dependent Resistors and a servo motor is integrated to supply maximum power by continuously orienting the panel in the direction of sunlight and thus always keeping it charged. This research aims to analyse the performance of a solar-powered thermoelectric refrigeration system. The model developed is a promising alternative for domestic refrigerators, accounting for a 44–63% drop in power consumption to cool a commensurate capacity refrigerator of 2.6L. From definitive experimentation, the lowest temperature of 15.15°C was achieved within the refrigeration chamber after powering the circuit for 136 seconds. Initially, the air inside the refrigeration chamber at 22.48°C (ambient temperature) was dropped by 7.33°C. A high COP of 0.54 is achieved on experimentation.

Solar Liquid Flat Plate Collector (LFPC) system used for low-temperature domestic water heating has wide applications. However, the conversion efficiency is observed to be poor since losses from collector surface is higher. Mostly heat transfer augmentation in solar collectors is one of the key issues in energy saving, compact designs and different operational temperatures. The present work focusses on coining an appropriate Heat Transfer Fluid (HTF) and internal grooves to the Heat Transfer Fluid (HTF) ducts to enhance the performance of LFPC, taking Mumbai as site for analysis. Experimental feasibility study at Mumbai city for four months unrolled maximum global radiation of 800 W/m² and 32.5°C of ambient temperature. Thermophysical analysis of three distinct base fluids namely Molten Salt, Dowtherm A and Therminol VP-1 showcased significant performance of therminol VP-1 with specific heat, density and thermal conductivity of about 1688.8 J/kg-K, 1351.6 kg/m³ and 20.99 W/mK respectively at 50°C. Similarly, three different internal groove profiles (plain, rectangular and trapezoidal) where analysed, of which trapezoidal profile showed improved system performance with maximum of 51.6°C as outlet temperature and 1478 W useful heat gain. The efficiency of trapezoidal profile (77.3%) was found to be 1.01 and 1.003% upfront of plain and rectangular groove profiles. Experimental values for LFPC system with water and plain duct was recorded to compare with other combinations. The enhancement achieved is helpful for addressing various green-house gas emissions and clean energy sustainability.

The aim of this paper is to assess the thermal performance of a parabolic trough collector where the thermophysical characteristics of the heat transfer fluid, the glass envelope, and the absorber pipe are temperature dependent for which we have created our own mathematical correlations. The structure of a parabolic trough collector consists of a reflecting mirror, a heat transfer fluid circulating in an absorber tube that is covered by a glass envelope. The studied model has been subjected to seasonal variations (solstices and equinoxes days) of solar radiation along with the concentrated heat flux reflected from the parabolic trough mirror for conditions at Tetouan city, Morocco. The amount of diffuse and beam solar radiation required has been modelled using the solar load model under Ansys Fluent software environment. The estimation of the heat transfer mechanism of our model has been done by solving Navier Stokes equations, also, the solar discrete ordinate model (DO) has been used to simulate radiation heat exchange on the receiver. The results have shown that the temperature of the heat collector element reaches its maximum values at equinoxes days compared to solstices days, also, it is found that the use of temperature-dependent properties enhances the thermal performance of the model by 1.4%.

Fault detection in photovoltaic (PV) arrays is one of the prime challenges for the operation of solar power plants. This paper proposes an artificial neural network (ANN) based fault detection approach. Partial shading, line-to-line fault, open circuit fault, short circuit fault, and ground fault in a PV array have been investigated, and a data set is synthesized to evaluate the impact on maximum power amplitude and number of power peaks under various exposure of irradiance and temperature. The ANN model has been trained considering irradiance, temperature, maximum power, and the number of power peaks corresponding to the different faulty conditions and non-fault situations. The considered ANN model has been optimized in order to increase the accuracy of fault identification. A particle swarm optimization-based algorithm has been employed to find the optimum number of neurons in the hidden layers to achieve the highest possible prediction accuracy on the test data set. The performance of the optimized neural network has been further cross-validated by an arranged data set containing all the types of faulty conditions. The effectiveness of the proposed technique is verified by comparing the results with existing methods.

Kesterite Cu₂ZnSnS₄ thin films were synthesized by the spray pyrolysis method with subsequent annealing at temperatures in the range from 425 to 525°C. To understand the impact of Ag on the Cu₂ZnSnS₄ structural properties, changes in the elemental and phase composition, as well as microstructure were studied by electron microanalysis, X-ray phase and Raman analysis, scanning probe microscopy and scanning electron microscopy. The obtained samples have a compact morphology without appreciable voids and pores and crystallize in the tetragonal structure of kesterite CZTS. Phase analysis indicated incorporation of Ag in different concentrations without formation of other impurity compounds. An increase in the annealing temperature leads to an increase in the coherent scattering region, while the stoichiometric ratio of metals to chalcogen approaches 1, remaining close to that upon Ag alloying.