Journal of Solar Energy Research
Volume:8 Issue: 3, Summer 2023

Solar tunnel dryers are innovative technologies that utilize solar energy to efficiently and cost-effectively dry agricultural products. By harnessing renewable energy, these dryers provide a sustainable alternative to conventional drying methods. The aim of this article is to examine a solar tunnel dryer that is employed to dry a variety of agricultural goods in Chandragiri Mandal, Tirupati (Andhra Pradesh), India under local weather circumstances. The dryer has a polycarbonate sheet that is 1 mm thick and 30 feet long by 12 feet broad. This sheet is utilized as a collector for material and for direct absorption on the item to be dried. About 300 kg can be loaded into the dryer with vegetables or agricultural products. Vegetables have been dried in a solar tunnel dryer in 1 hours from initial moisture content of roughly 85% to 45% whereas open-air drying takes 18 hours. The temperature within the dryer is considerably higher between 30 and 40 degrees Celsius than the ambient temperature. It has been determined that the typical thermal efficiency is around 53.1%. Solar tunnel dryers, such as reduced drying time, improved product quality, and decreased post-harvest losses.

Photovoltaic (PV) systems are susceptible to lightning strikes. In this paper, a new accurate and efficient electromagnetic transient (EMT) model of grounding systems (GSs) is presented. The proposed approach considers the impact of frequency-dependent (FD) modeling of GSs on the overvoltage values in PV systems in time domain analysis. The proposed wide-band model is significantly accurate for various types of GSs (single-port and multi-port GSs) and models the frequency dependence of the soil electrical parameters based on experimental data (conductivity and relative permittivity). The proposed model can be implemented in time domain without any GS impedance matrix inversion, so it has less complexity compared to previous approaches. Most of the existing studies suffer from low accuracy in the PV system modeling during lightning transients because of neglecting the effects of the mounting system, metal frame, and mutual coupling, which are considered in the present work. The results demonstrate that the PV factors and frequency dependence of soil have a great effect on the PV system overvoltages. The proposed model offers improved accuracy by covering the entire frequency range of interest. Additionally, it takes into account the mounting system, metal frame, and mutual coupling in EMT analysis.

This paper presents an innovative Asymmetrical Single-Phase Nine Level Inverter (ASRNLI) that stands out among various available configurations. The design achieves a staircase-like voltage pattern with the highest number of levels while utilizing a reduced number of components. Compared to conventional systems, asymmetric multilevel inverters require fewer components yet manage to create a cascade structure with multiple output levels. The ASRNLI configuration consists of two independent DC sources and 10 switches, allowing it to generate any desired level. This setup offers several advantages, including improved output voltage quality attributed to the switches' low blocking voltage. It proves particularly valuable in scenarios where asymmetric DC voltage sources are accessible, such as in modern electric vehicles and AC mini-grids powered by renewable energy sources. To generate gate pulses, the ASRNLI employs the level-shifted pulse width modulation approach. Validation of the suggested ASRNLI configuration was carried out through both MATLAB simulations and the construction of a prototype. The output waveform demonstrated a Total Harmonic Distortion (THD) of 13.50% at the highest fundamental voltage of 400V. Throughout this article, the effectiveness of the ASRNLI configuration is supported by findings from simulations and experimental tests, showcasing its potential as a promising solution for practical applications.

This paper presents a preliminary study on the design of an off-grid solar PV system for an isolated island. It conducts a case study for Sukun Island that has the highest potential for solar energy in Indonesia. The study includes climate research, consumption estimation, system sizing, simulation, quasi-dynamic analysis, and environmental analysis. Climate data from Solargis and Meteonorm is utilized. The greatest difficulty in conducting an initial PV system planning study is pre-sizing. Using PVsyst simulation, this study confirms the validity of simplified theoretical calculations stated in the paper for system pre-sizing, with the theoretically calculated system (285 kWp solar power plant with 2.91 MWh storage system) managed to get a Loss of Load Probability (LOLP) valued at 0.17%, meeting applicable standard. The proposed method of combining simulation using PVsyst and quasi-dynamic analysis using DIgSILENT Powerfactory can be used to verify the power stability of the designed PV-BESS system. The simulations attest to the use of battery energy storage systems (BESS) in maintaining the stability of the solar PV network by preventing the vulnerability of electrical networks to insufficient electricity (loss of load) and voltage sags, proven by the minimum voltage level of 96.6%, meeting international safety standards.

This article proposes a technique to improve power quality and eliminate current and voltage harmonics. The robustness of the system functioning in various operating modes is the key contribution of this research. Research findings demonstrating the PV array insulation, load variation, and grid unavailability are employed for transitioning between modes and are used to assess the performance of a grid-interfaced PV-BES (Battery Energy Storage) system. The system also operates in constant and variable power modes to provide power smoothening and reduce the load on the distribution grid during peak demand. This system also turns out to be capable of operating in an islanding mode to provide the load with uninterrupted power. For this, a grid-tied voltage source converter (VSC) with effective control logic is designed. A PI controller was used in the existing model to enhance the system's performance, but due to various disadvantages, a fuzzy logic controller has been implemented in the proposed system, which has more advantages and aids in suppressing harmonics and enhancing the reliability of the power. Consequently, a comparison of the controller is done in this article. For implementing the performance of this system, MATLAB/Simulink software is used.

Due to the challenges of fossil fuels, renewable resources such as wind, solar and ocean are applied for electric power production. Among different kinds of renewable resources, the potential of solar energy is significant in Iran. The electricity cost produced by parabolic trough collectors is low. Accordingly, this paper aims to study the reliability performance of this plant. To this end, a multi-state reliability model considering both failures of composed components and variation of produced power caused by variation of sun irradiance is developed for solar power plants with parabolic trough collectors. To reduce the number of power states of the model, the fuzzy c-means clustering method and XB index are applied. The obtained reliability model of solar plants is utilized for analytical reliability analysis of electric networks. Numerical outcomes of adequacy analysis of RBTS and IEEE-RTS results integration of parabolic trough collectors improve reliability indices of the system. However, due to the variation of sun irradiance results in the variation of plant output, improvement of reliability indices caused by parabolic trough collector is less than traditional plants. Besides, by comparing the outcomes obtained by the proposed work and Monte Carlo method, the accuracy of the suggested method is approved.