Journal of Solar Energy Research Updates

Glucose Sensing Optionally in Optical and Optoelectrical Modes Based on Au-TiO2 Schottky Nanojunctions

Lu Ma — 2024-02-27

Abstract: In recent years, metallic nanostructures have been extensively researched in the field of plasmonic for optical and optoelectronic applications such as biochemical sensing. However, an additional optoelectronic converter or spectrometer is usually required for the sensing application. Herein, the orderly-patterned Au-TiO₂ Schottky junction with an Al film that we coupled, which simultaneously works as an optical reflector and conducting layer, can achieve optical sensing of glucose by exciting surface plasmon resonance associated with the environment, and meanwhile can realize glucose detection with direct electrical-signal readout by collecting the photogenerated carriers inside the Au nanostructures and TiO₂ film. When used in optical mode, the designed sensor shows a sensing sensitivity of up to 1200.0 nmRIU^-1 in numerical calculation, and the measured value is 346.1 nmRIU^-1. When used in optoelectrical mode, the glucose sensor under one-sun illumination obtains a sensitivity of 70.0 µAM^-1cm^-2 in the concentration range of 0–10 mM, with a detection limit of 0.05 µM (Signal/Noise=3). Simulation and experimental results demonstrated that the Al-film-coupled Au-TiO₂ Schottky nanojunction can monitor glucose concentration optionally in optical and optoelectrical modes, which presents an alternative route to the miniaturized, portable, and multi-functioned sensors.

Accelerated Polymer Photodegradation

Cynthia Paola Gutiérrez-Castellanos — 2024-04-05

Abstract: This article presents preliminary results of the accelerated degradation of polymers using concentrated solar radiation. For this purpose, a passive solar concentration prototype was designed, which consists of four trapezoidal mirrors placed in the shape of an inverted truncated square pyramid. The mirrors are placed at an angle of 30° respect to the zenith. The prototype has a square base of 46 cm x 46 cm where the polymers to be irradiated are placed and a geometric concentration ratio, CR_g, of 1.89. The mass change was determined after 30 days of exposure to solar radiation, and the temperature variation of some samples as a function of irradiance was obtained. In addition, a computer simulation was carried out using the free access software Energy2D. Some polymers maintained their flexible mechanical properties, such as PET (type 1), others were partially embrittled, while type 2, 5 and 7 polymers were completely embrittled. It was possible to reduce the degradation time of different types of commercial polymers, while polymers exposed to non-concentrated radiation and without exposure remains intact. Embrittled polymers can be used as waterproof material in slabs and pre-cast walls, as well in applications where they are not exposed to solar radiation. On the other hand, the polymers that remained intact must be used in applications with permanent radiation exposure, such as in flower pots, plastic parts for automobiles, etc.

A Modified Perturb and Observe Algorithm in Photovoltaic Maximum Power Point Tracking System

Wei Xie — 2024-05-11

Abstract: The power output of the photovoltaic (PV) array is nonlinear, and maximum power point tracking (MPPT) is required to boost the efficiency of solar energy generation. The traditional perturb and observe algorithm is frequently used, but it is difficult to comprehensively consider the tracking accuracy and response speed at the same time. Misjudgment occurs when the solar insolation changes drastically. In view of these shortcomings, this paper presents a variable step size threshold search algorithm. The modified algorithm can quickly track the maximum power point and restrain fluctuations near the maximum power point. Matlab is utilized to simulate and prove the effectiveness of this modified algorithm.

Design Principle and Development Trends of Silicon-Based Anode Binders for Lithium-ion Batteries: A Mini Review

Hongyang Zhang — 2024-05-15

Abstract: Silicon (Si), recognized as a promising alternative material for the anodes of lithium-ion batteries, boasts a high theoretical specific capacity and abundant natural availability. During the preparation of silicon-based anodes, binders play a pivotal role in ensuring the cohesion of silicon particles, conductive agents, and current collectors. The structure and performance of these binders are critical for the mechanical stability, electrical conductivity, and stress dissipation capacity of the anodes. This review initially outlines the structural characteristics of various binders, including linear, branched, and three-dimensional cross-linked types. It then delves into the relationship between the structure and properties of these binders in the context of their application in high-performance lithium-ion batteries, focusing on their mechanical properties, electrical conductivity, and self-healing capabilities. Particular attention is given to the design strategies for binders that facilitate stress dissipation, with an emphasis on integrating multifunctional polymer binders renowned for their superior conductive and self-healing features. Such binders contribute to the formation of a robust three-dimensional network structure via multiple bonding mechanisms, including chemical, non-covalent, and coordination interactions. This configuration significantly enhances the adhesion between silicon particles, thereby facilitating the efficient dissipation of stress, which is a key aspect for ensuring the long-term cycling stability of lithium-ion batteries. Lastly, the paper explores future development directions for silicon anode binders, advocating for a thorough investigation into the synergy of diverse structural and functional combinations, with the aim of advancing the performance and practical application of silicon-based lithium-ion batteries.

Properties of ((CH3NH3)1-xCsx)3Bi2I9: (x=0-1.0) Hybrid Perovskite Solar Cells with Chlorobenzene Treatment

M.F. Achoi — 2024-05-31

Abstract: Hybrid-perovskite solar cells, a promising lead-free perovskite material, have been attracted for optoelectronic applications due to an excellent optical and electrical properties with low production cost. Herein, methylammonium bismuth iodide and cesium bismuth iodide were mixed to form hybrid structure for the improvement of photovoltaic properties, which were fabricated using all-solution processed multi-step spin coating technique with changing the composition, x, of CBI, ((CH₃NH₃)_1-xCs_x)₃Bi₂I₉; (x=0 – 1.0). Chlorobenzene was added to the solution to improve the surface morphology. By optimizing the composition of CBI in MBI, the morphology, structural and optical properties of HPeSCs have been improved. It showed that the morphology is homogeneous, compact and a uniform layer, while the crystallinity shows an improvement as well. The open circuit voltage, the short circuit current and the power conversion efficiency were much improved with using hybrid structure. Our study shows that the significance of the hybridization process gives a new route in fabricating a better active absorber layer of PeSCs in the future.

Impact of Ground Heat Source Addition on Main Performance Parameters of Solar Chimney Power Plants: A Numerical Study

Erdem Cuce — 2024-06-05

Abstract: Solar energy systems can be an alternative to fossil fuels and are vital for a sustainable environment. It is promising that solar chimney power plants (SCPPs), which are among the solar energy systems, provide 24-hour power output (PO) and can work integrated with other systems. This study is based on the Manzanares pilot plant (MPP) and demonstrates satisfactory performance with an additional heat source to be integrated into the ground of the system during hours when solar radiation is weak. The performance of the system at different source temperatures is compared with the reference case, with the model verified using the RNG k-ε turbulence model through a 3D CFD study. In fact, it is seen that the PO of the system, which yields a PO of around 10 kW at 200 W/m² solar radiation in the reference case, exceeds 80 kW with a source temperature of 200°C. From the results, it can be noticed that the system can also output power in the evening hours when there is no sun. With an additional heat source of 200°C during non-sunlit hours, the system gives more than 75 kW PO. This PO is 50% more than the maximum PO of 50 kW in the reference case.

Biogas Heat Pump Power Supply Based on Smart Grid Functioning Solar Electric System Network

Eugene Chaikovskaya — 2024-09-26

A comprehensive integrated solar power plant system has been developed to support the operation of a biogas plant based on a heat pump, for which fermented wort is a low-potential energy source. The change in the power factor of the solar power system connected to the grid and the temperature of the coolant entering the heat exchanger built into the methane tank are predicted. Promising solutions include changing the power of the heat pump compressor to maintain biogas production, unloading fermented wort and loading fresh material while maintaining the power factor of the grid solar system and changing the level of electricity transmission to the grid. The voltage at the input of the hybrid inverter, the voltage at the output of the frequency converter to assess their ratio and the voltage frequency are constantly measured. When changing the voltage at the input of the hybrid inverter from 240 V to 600 V, promising solutions were adopted to reduce the power of the heat pump from 3.14 kW to 1.58 kW in the production of biogas 352.5 m³/day to maintain the temperature of the heating coolant entering the heat exchanger built into the methane tank at 55° C - 45 °C in order to obtain biogas, unload fermented wort and load fresh raw materials. There is an increase in the power of electricity transmission to the grid from 0.27 to 1 and an increase in the power factor by 40% from 0.58 to 0.98. The use of the developed Smart Grid technology allows preventing peak loads of the power system, reducing electricity consumption from the grid by up to 30%.

The Energy Consumption Comparison of Temperature Difference-based Defrosting Exit Method and Time-based Defrosting Exit Method with Various Static Pressure Differences

Wu Yufan — 2024-12-04

The time-based defrosting exit method(TDEM) has been widely used in cold storage, but the issue of energy consumption has been heavily criticized. In this paper, a temperature difference-based defrosting exit method(TDDEM) is proposed to compare with TDEM. Firstly, a parameter acquisition system of cold storage is constructed, and the experimental setup is conducted to determine the experimental parameters. Subsequentially, the range of defrosting static pressure difference is determined based on pre-frosting experiment, and the defrosting experiment of TDEM and TDDEM are carried out at five various static pressure difference conditions, 16Pa, 14Pa, 12Pa, 10Pa and 8Pa, respectively. The results show that the temperature fluctuations per defrosting events of TDEM are more severe compared to TDDEM, with with average increases of 102.2%, 91.6%, 59.3%, and 46.5%, respectively. Energy consumptions of TDDEM are markedly lower than TDEM, with reductions of 21.4%, 15.7%, 14.09% and 14.59%, respectively. Whether TDEM or TDDEM, the lowest energy consumption is occurred at 10Pa, and highest is 8Pa.