Solar Applications Research Articles

Analysis of WRF-solar in the estimation of global horizontal irradiation in Amapá, northern Brazil

Global horizontal irradiance (GHI) was simulated using version 4.3.1 of the WRF-Solar model over the state of Amapá in the northern region of Brazil. The performance of the Fast All-sky Model for Solar Applications (FARMS) algorithm, called WsolarAPf, was evaluated. The algorithm proposed by the Baseline Surface Radiation Network was used to treat hourly data from the automatic meteorological station of the National Institute of Meteorology in the city of Macapá-AP. Two cumulus parameterizations were needed to represent the rainy and less rainy periods. The modeling used input data from ERA5 reanalysis. Using cluster analysis, it was possible to estimate the typical meteorological year representative for a large area. The use of the FARMS algorithm reduced the relative RMSE of the GHI during winter (JJA) and austral spring (SON), from 26 % to 16 % in austral winter and from 17 % to 12 % in austral spring. The average daily maximum of GHI occurs at 13:00 local time during all seasons, and WRF-Solar showed it at 13:00 and 14:00 in the rainy season and 12:00 and 13:00 in the less rainy season. The suggestion to explore the development of an optimal combination of the two model predictions can be implemented using FARMS.

Performance Analysis and Optimization of a Channeled Photovoltaic Thermal System with Fin Absorbers and Combined Bi-Fluid Cooling

The conversion efficiency of photovoltaic (PV) cells can be increased by reducing high temperatures with appropriate cooling. Passive cooling systems using air, water, ethylene glycol, and air/water+TiO2 nano bi-fluid froth in the duct channel have been studied, but an overall assessment is essential for its possible application. In the present work, a numerical study is adopted to investigate the impact of the fluid-duct channel type on the electrical and thermal efficiency of the photovoltaic thermal (PVT) collector. Such investigation is achieved by means of a MATLAB R2022b code based on the Runge–Kutta (RK4) method. Four kinds of fluid duct channels are used to optimize the best fluid for improving the overall efficiency of the investigated PVT system. The numerical validation of the proposed model has been made by comparing the numerical and experimental results reported in the literature. The outcomes indicate that varying the duct channel nature affects mainly the electrical and thermal efficiency of the PVT collector. Our results validate that the nature of the fluid affects weakly the electrical efficiency, whereas the thermal efficiency is strongly affected. Accordingly, it is observed that PVT collectors based on nano bi-fluid air/water+TiO2 give the best performance. In this context, an appreciable increase in the overall efficiency of 22% is observed when the water+TiO2 fluid is substituted by air/ water+TiO2 nano bi-fluid. Therefore, these motivating results make the PVT nano bi-fluid efficient and suitable for solar photovoltaic thermal applications since this system exhibits a daily overall efficiency of about 56.96%. The present work proves that controlling the design, cooling technique, and nature of the cooling fluid used is a crucial factor for improving the electrical, thermal, and overall efficiency of the PVT systems.

Dual internal electric field induced by Ni3C selectively deposited onto Mn2O3 on faceted BiVO4 for boosting photocatalytic oxygen evolution

The oxidation reaction between charge and water for photocatalyst has restricted overall water splitting efficiency. Herein, the non-noble-metal Ni3C acting as an electron sink were selectively deposited onto Mn2O3 on faceted BiVO4 via electrostatic self-assembly, synergistically creating faceted heterostructure with dual internal electric field (IEF) for photocatalytic water oxidation. Resultantly, a remarkable visible light-driven photocatalytic O2 evolution rate was observed to be 2736.5 μmol g−1 h−1 with an apparent quantum yield of 5.57 % at 400 nm. The significantly improved activity mainly stemmed from the giant dual IEF, dramatically accelerating exciton separation and prolonging the lifetime of charge carriers. Moreover, the photocatalysts without activity attenuation were considerably stable and reused with recyclability utilizing the magnetic nature in practical application. By combining with the self-induced IEF by exposed {001} facet of BiVO4 for improving photocatalytic activity, this work could throw light on the design of faceted heterostructure in solar energy conversion application.

Packing Characteristics and Heat Transfer Performance of Non-Spherical Particles for Concentrated Solar Power Applications

Packing Characteristics and Heat Transfer Performance of Non-Spherical Particles for Concentrated Solar Power Applications

Preparation and photothermal properties of latent functional thermal fluid based on size-controllable phase change nanocapsules

To improve the solar heat utilization efficiency of working fluid in direct solar collector, a novel latent functional thermal fluid (LFTF) based on self-designed 1-octadecanol@silica phase change nanocapsules (NEPCMs) with excellent heat storage capacity and photothermal conversion efficiency were prepared. The NEPCMs prepared by sol–gel method were dispersed in water containing multi-walled carbon nanoparticles to prepare the LFTF. The prepared NEPCMs have high encapsulation efficiency (85.12 %) and melting phase change enthalpy (235.1 J/g), controllable particle size (27.13–167.30 nm), excellent thermal stability and cycle stability. The LFTF containing 10 wt% NEPCMs was considered the optimal choice for its excellent dispersion stability (zeta potential 35.63 mV), thermal storage capacity (peak specific heat capacity 5.11 J·g−1·K−1) and superior photothermal conversion efficiency (up to 98 %), which is roughly 3.29 times that of water. These results offer valuable insights for the future development of LFTF in the field of solar thermal applications.

Tuning of optical, thermodynamic, and thermoelectric properties of Cs2CuBiX6 (X = Cl, Br, I) halide perovskites for solar cells and energy harvesting applications

The double perovskites are outstanding materials for solar cells and transport applications to clean harvest energy. Therefore, the Cs2CuBiX6 (X = Cl, Br, I) are discussed comprehensively for energy harvesting by modified Becke and Johnson (mBJ) potential. The studied DPs fit the structural, mechanical, and dynamic stability scale by tolerance factor, Born–Huang criteria, and phonon dispersion band structures. The band gaps (1.20, 1.0, 0.70) eV for (Cl, Br, I) based DPs ensure the Cs2CuBiCl6 has an absorption band in the visible region while Cs2CuBiBr6 and Cs2CuBiI6 has an absorption band in the infrared region. Heavy elements’ spin–orbit coupling effect (Cs, Bi) reduces the band gap to 0.08 eV. Thermoelectric behavior regarding the merit scale against dopant carriers and temperature has been elaborated. The ultralow lattice thermal conductivity, large Debye temperature, hardness, and melting temperature increase their implication for thermoelectric and other thermodynamic applications. The variation in band gap makes them important for diverse optoelectric and thermoelectric applications. The Cs2CuBiCl6 with a band gap of 1.20 eV is suitable for solar cells, while Cs2CuBiBr6 and Cs2CuBiI6 with band gaps of 1.0 eV and 0.70 eV are significant for thermoelectric generators.

Development of Ti3SiC2 MAX phase tubular structures for solar receiver applications

Solar receiver tubes are key components of concentrating solar-thermal power (CSP) systems that harvest solar energy. For better efficiency, the Gen3 CSP receivers, which collect heat into a heat transfer fluid, require a temperature exceeding 700 °C during operation and need to perform under extreme conditions of high temperature and high thermal stress. Operators are seeking CSP designs using new high-temperature structural materials with high thermal conductivity and high creep resistance to achieve a design life of 30 years and thus help recover the plant capital cost sooner. MAX phase materials, which consist of an early transition metal element, an A-group element, and carbon or nitrogen, are expected to exhibit high creep resistance as well as high fracture toughness. In this paper, we describe fabricating both (1) dense Ti3SiC2 MAX phase disks and (2) short-length tubes using field-assisted sintering technology (FAST). First, the disk samples that we fabricated are fully dense and contain ≈90 % Ti3SiC2 MAX phase materials and ≈10 % TiC phase materials. We determined a flexure strength of 519 ± 32 MPa by conducting a four-point bending test at room temperature with rectangular bar samples of ≈100 % density. The thermal conductivity of the Ti3SiC2 MAX phase samples, measured by light-flashing analysis, decreases linearly from a value of 41 W·m−1·K−1 at room temperature to a value of 36 W·m−1·K−1 at 650 °C. A solar reflectance measurement of the Ti3SiC2 MAX phase revealed that, temperature increases from 400 to 1400 °C, thermal emittance increases from 0.39 to 0.49, while selectivity decreases from 1.8 to 1.4, respectively. Whereas the surface oxidized MAX phase samples after 100 h exposure to air at 1000 °C exhibit that of SiC.Next, we discuss fabrication of the crack-free Ti3SiC2 MAX phase tubular structures accomplished by using FAST processing in graphite bedding. A Ti3SiC2 MAX phase content of > 95 % with traceable ≈3% remaining TiC phase and ≈15 % porosity were demonstrated after high-temperature annealing. An average fracture strength of ≈250 MPa was determined with Ti3SiC2 MAX phase tubes of ≈85 % density by diametral compression testing at room temperature. Our work demonstrated that using FAST processing to produce Ti3SiC2 MAX phase tubular structures for CSP receiver applications is a viable approach.

Tunable distributed Bragg reflector developed by magnetron sputtering to improve the power conversion efficiency of transparent IR cells for solar energy harvesting applications

Transparent organic photovoltaic (TOPV) cells integrated into windows are key to reducing the carbon dioxide emissions associated with the building sector. However, TOPV cells that reach a compromise between efficiency and transparency must still be developed. In addition, to implement this technology in glass production companies, the materials and processes used in TOPV cell development must be compatible with producing these devices on an industrial scale. Here, an infrared (IR) cell combining a PC60BM-based active material, ITO/ZnO as the back transparent electrode, PEDOT:PSS and ITO or Ag as the top transparent electrode, and a DBR as an antireflective coating was developed and applied on 625 mm2 glass samples. The structure of the DBR based on titanium dioxide (TiO2) and silicon dioxide (SiO2) monolayers was adjusted to the IR cell absorption spectra to reach a power conversion efficiency (PCE) of 5 and 4.3, and an average visible transmission (AVT) of 41 % and 51 % for ITO and Ag top electrodes, respectively. The manufacturing route of these devices involved commercial polymers and coatings that can be deposited by technologies already applied in the glass industry, such as magnetron sputtering or thermal evaporation. Therefore, the IR cells developed here showed a good compromise between efficiency, transparency, and large-scale production manufacturability.

Design and simulation of zeta solar charge controller with artificial neural network MPPT

Fossil fuel are non-renewable energy sources with constrained reserves. This advocates renewable energy as a viable alternative for electricity generation. PV is a renewable energy source that harnesses solar energy. The current issue with PV is its low efficiency and elevated cost. Photovoltaic control devices and Maximum Power Point Tracking (MPPT) mimic human neural networks in processing multiple conditions and providing solutions from current reference data to optimise photovoltaic power. This technique is known as Artifical neural network (ANN). This method uses a zeta converter to adjust the photovoltaic voltage to supply specific loads, allowing ANN to optimize power as sunlight intensity changes. In this work, a charge controller for solar applications was designed using MPPT algorithms. This is responsible for overseeing the battery circuit and producing PWM signals to regulate zeta converter according to the battery voltage. The artificial neural network (ANN) received as inputs temperature and irradiation (G). Several simulations verified the efficiency of the suggested MPPT algorithm. The Zeta solar charge controller (ZSCC) device achieved up to 92% efficiency with low irradiance. The proposed ANN-based MPPT controller and perturb-observed Maximum Power Point Tracking (MPPT) algorithm were compared in different solar insolations. The simulation results show that MPPT-ANN can track power up to 2000 Watts for a 2000 WP photovoltaic in 0.056 seconds, with no power oscillations at the MPP.

Amphipathic Astaxanthin Additive for Low Voltage-loss Perovskite Solar Cells With Enhanced Quasi-Fermi Level Splitting and Solar Hydrogen Production Application.

Even though the power conversion efficiency (PCE) of perovskite solar cells (PSCs) is nearly approaching the Schottky-Queisser limit, low open-circuit voltage (Voc) and severe Voc loss problems continue to impede the improvement of PCEs. Astaxanthin (ASTA) additive is introduced in the formamidinium lead triiodide (FAPbI3)perovskite film as an additive, which can facilitate the transportation of charge carriers and interact with Pb2+ by its distinctive groupings. Furthermore, the addition of ASTA decreases the defect's active energy, regulates the deep-level defect by filling up the grain boundaries (GBs), and promotes the crystallization of perovskite film. Remarkably, an enhanced quasi-Fermi level splitting (QFLS) of 1.164eV and a reduced Voc loss of only 96mV are realized. The champion PCE of 24.56% is attained by ASTA-modified PSCs on the basis of 22.75% PCE. Moreover, the PSCs that underwent ASTA modification demonstrate improved operational stability, ensuring consistent output in real-world scenarios. Furthermore, PSCs with an active area of 1 cm2 are used for water electrolysis to produce hydrogen and exhibit a PCE of 22.41%. This work offers an environmentally benign solution to address the inherent issues of FAPbI3 PSCs and lays the groundwork for the development of a prospective solar hydrogen production application.

Development and performance investigation of coffee husk-derived carbon-based nanofluid for solar thermal applications

Managing agricultural waste effectively is a serious concern, particularly in agrarian economies, where poor disposal practices cause environmental and public health problems. This paper discusses the synthesis of a carbon-based nanofluid from coffee husk char for solar thermal applications, utilising pyrolysis as an effective method for valorising agro-residue. The synthesis used the left-over solid residue during coffee husk pyrolysis after gaseous product extraction. The feasibility of the synthesized fluid for solar thermal application is studied by physical, chemical and optical characterisations. The synthesized fluid had a thermal conductivity of 0.87 W/mK and a pH of 10.26. The fluid was stable with a zeta potential value of −59.4 mV. The mean size of particles in the synthesized fluid was 6.24 nm. The optical characteristics of the synthesized fluid were studied from UV–Vis absorption spectroscopy. The solar-weighted absorption fraction of carbon-based nanofluid was 62.6 %, and that of deionised water was 12.3 %. When investigated with a solar simulator (at irradiance values of 700, 800, 900, 1000 and 1100 W/m2), the maximum improvement in photothermal conversion efficiency was 14.35 % at 1100 W/m2. At all irradiance levels, the sensible heat gain and the photothermal conversion efficiency were found to be greater than those of deionised water.

CuxS films as photoelectrodes for visible-light water splitting

Copper sulfides are appealing semiconductors for optoelectronics applications requiring visible-light activity, such as solar water splitting, due to their relatively low band gaps and earth-abundance. This study investigates the effect of deposition conditions, including substrate temperature and background gas pressure, on the characteristics and photoelectrochemical performance of copper sulfide (CuxS) films grown by pulsed laser deposition (PLD) on Si (100) substrates. The results reveal that varying the deposition parameters influences the crystalline phases, morphology, and optoelectronic properties of the films. For deposition at room temperature, the films exhibited covellite CuS phase, while elevated deposition temperatures (250 °C and 500 °C) led to the formation of Cu1.8S and Cu2S phases, resulting in narrowing of the band gap, with the increased temperature also enhancing the film crystallinity and surface roughness. As a result of the changes in film morphology and crystal structure, photocurrent density magnitudes increased with higher deposition temperatures, reaching 0.747 mA/cm2 at −0.8 V for films deposited at 500 °C under vacuum, at least an order of magnitude higher than reported in comparable previous studies of the photoelectrochemical performance of CuxS. Background gas pressure only slightly affected the photocurrent density, with changes in photoactivity also correlating with changes in film roughness and band gap. The results demonstrate the good visible-light activity and behavior of CuxS as a stand-alone photoelectrode material, with tunability based on the fabrication conditions, suggesting their potential use in photoelectrochemical and other solar energy conversion applications.

Artificial Intelligence-Based Improvement of Empirical Methods for Accurate Global Solar Radiation Forecast: Development and Comparative Analysis

Artificial intelligence (AI) technology has expanded its potential in environmental and renewable energy applications, particularly in the use of artificial neural networks (ANNs) as the most widely used technique. To address the shortage of solar measurement in various places worldwide, several solar radiation methods have been developed to forecast global solar radiation (GSR). With this consideration, this study aims to develop temperature-based GSR models using a commonly utilized approach in machine learning techniques, ANNs, to predict GSR using just temperature data. It also compares the performance of these models to the commonly used empirical technique. Additionally, it develops precise GSR models for five new sites and the entire region, which currently lacks AI-based models despite the presence of proposed solar energy plants in the area. The study also examines the impact of varying lengths of validation datasets on solar radiation models’ prediction and accuracy, which has received little attention. Furthermore, it investigates different ANN architectures for GSR estimation and introduces a comprehensive comparative study. The findings indicate that the most advanced models of both methods accurately predict GSR, with coefficient of determination, R2, values ranging from 96% to 98%. Moreover, the local and general formulas of the empirical model exhibit comparable performance at non-coastal sites. Conversely, the local and general ANN-based models perform almost identically, with a high ability to forecast GSR in any location, even during the winter months. Additionally, ANN architectures with fewer neurons in their single hidden layer generally outperform those with more. Furthermore, the efficacy and precision of the models, particularly ANN-based ones, are minimally impacted by the size of the validation data sets. This study also reveals that the performance of the empirical models was significantly influenced by weather conditions such as clouds and rain, especially at coastal sites. In contrast, the ANN-based models were less impacted by such weather variations, with a performance that was approximately 7% better than the empirical ones at coastal sites. The best-developed models, particularly the ANN-based models, are thus highly recommended. They enable the precise and rapid forecast of GSR, which is useful in the design and performance evaluation of various solar applications, with the temperature data continuously and easily recorded for various purposes.

Improving the National Solar Radiation Database (NSRDB) Using a Physics-Based Direct Normal Irradiance (DNI) Model

The National Solar Radiation Database (NSRDB) is a widely used resource providing satellite-derived solar data across the United States and globally. While the NSRDB employs a physical model for computing global horizontal irradiance (GHI), its current method for estimating cloudy-sky direct normal irradiance (DNI) relies on surface observations and empirical models. Recently, a novel physics-based approach, the Fast All-Sky Radiation Model for Solar applications with DNI (FARMS-DNI), was developed to enhance the DNI forecasting. FARMS-DNI incorporates both direct and scattered solar radiation within the circumsolar region, resulting in improved day-ahead DNI predictions when integrated into the Weather Research and Forecasting model with Solar extensions (WRF-Solar). This study integrates FARMS-DNI into the NSRDB algorithm to generate high-resolution DNI data from satellite resources. Our findings reveal that FARMS-DNI effectively mitigates the substantial DNI overestimation present in the conventional NSRDB across surface sites, particularly in conditions categorized as cloudy overcast. Consequently, this innovative model substantially enhances the overall accuracy of the NSRDB.

Exploring the Optoelectronic and Photovoltaic Characteristics of Lead‐Free Cs2TiBr6 Double Perovskite Solar Cells: A DFT and SCAPS‐1D Investigations

AbstractIn recent times, the remarkable advancements achieved in the field of perovskite solar cells (PSCs) have sparked significant research efforts aimed at enhancing their overall performance because of their exceptional optoelectronic properties. Due to the toxicity of lead (Pb), the emergence of Ti‐based (Cs2TiBr6) double‐halide PSCs is regarded as a good alternative to Pb‐based PSCs. Here, density functional theory (DFT) calculations are performed to examine the prospect of Cs2TiBr6 perovskite as a layer of absorber for photovoltaic cells (SCs). These computations looked at the material's structural, optical, and electrical characteristics. The density of states (DOS) results demonstrate strong conductivity, principally provided by the 4p states of Br, whilst Ti‐3d and Cs‐5p orbital electrons offer insignificant contributions. The electronic band structure discloses a direct band gap of 1.534 eV. The covalent connections that exist between Ti and Br atoms and the robust electronic charge density around the Ti atom both demonstrate a significant buildup of electronic charge along the 100 planes. The dielectric function and the coefficient of absorption have significance irrespective of lower energies because it is extremely valuable for solar energy applications. The UV absorption peaks of Cs2TiBr6 have a maximum of ≈15.51 eV and are magnified with photon energy up to 2.46 eV, indicating that it may have potential for solar applications. This work also investigated a good combination of the hole transport layer (HTL) and electron transport layer (ETL) with the Cs2TiBr6 absorber layer. AZnO, Nb2O5, LBSO, and Zn2SnO4 are executed as the ETLs, and MoO3, CuAlO2, MEH‐PPV, ZnTe, CNTS, GaAs, MoS2, PTAA, Cu2Te, Zn3P2 are considered as the HTLs to identify the best HTL/Cs2TiBr6/ETL combinations using the SCAPS‐1D numerical simulation. Among all configurations, ITO/LBSO/Cs2TiBr6/CNTS/Au is examined as the best‐optimized structure of Ti‐based PSC, with JSC of 26.63 mA cm−2, a VOC of 1.123 V, FF of 82.94%, and a power conversion efficiency of 24.82%. To validate the findings, PV parameters like the effect of generation rate, recombination rate, J−V, and Q‐E characteristics are evaluated. The effect of series and shunt resistance and structure working temperature are explored to observe the effect of these on PSC devices. The accomplished outcomes suggest that Cs2TiBr6 can be viewed as an optimistic material for PSCs for its higher stability and environment‐friendly characteristics.

Optimizing novel perovskite Mg3AsBr3 through uniaxial stress: a comprehensive study of its potential in solar and optoelectronic applications

This study presents a detailed investigation into optimizing the novel perovskite Mg3AsBr3 through uniaxial stress for enhanced performance in solar and optoelectronic applications. Using Density Functional Theory (DFT), we examined its structural, electronic, and optical properties under uniaxial stress from 0.5 to 5.0 GPa. Key findings include the tuning of the material’s bandgap from 1.485 eV (without stress) to an optimized range closer to 1.13581 eV under 5.0 GPa, demonstrating potential for improved solar cell efficiency. Our findings reveal a nuanced response of the material’s absorption coefficients at critical energies of 2.92 eV and 4.0 eV, where a descending trend with increasing pressure was observed, indicating a plateau at 1.5 GPa and an anomalous increase at 2.5 GPa. This behavior underscores the significance of stress between 2.5 GPa to 5.0 GPa in tailoring the optical responses essential for enhancing solar absorption efficiency in the ultraviolet to visible light range (300–800 nm). Notably, the dielectric constant increased gradually with stress, peaking at 6.003 under 0.5 GPa and slightly diminishing at 5.0 GPa, suggesting enhanced polarization and intrinsic response to electric fields under mechanical stress. Our research highlights the potential of stress engineering in optimizing perovskite materials for renewable energy applications, offering a pathway to high-efficiency, low-cost solar cells.

The Advancement of Artificial Intelligence's Application in Hybrid Solar and Wind Power Plant Optimization: A Study of the Literature

The harnessing of solar, wind, and hydroelectric energy sources has rendered them easily accessible renewable resources, owing to their abundant availability. There is a growing body of research evincing interest in the deployment of hybrid renewable energy systems. Over recent decades, adopting hybrid technologies has engendered a positive trend, marked by broader considerations of configurations and applications within these systems. This study analytically examines the potential of hybrid solar and wind energy harvesting devices. As such, the project aims to extensively evaluate relevant literature and statistical analysis of data extracted from journal papers published between 2004 and 2023. A specific objective is to develop a complete database matrix surrounding multiple categories, including component configurations, methodological approaches, and supporting software infrastructures. Moreover, an assessment of the socio-economic, environmental, and ecological impacts of these systems is undertaken to ascertain their salience. Furthermore, this inquiry delves into the optimization strategies of these systems leveraging artificial intelligence methodologies. Critical lacunae identified during this review pertain to more emphasis on optimization metrics for PV-wind hybrid energy systems, impeding a holistic understanding of their implications on energy, economics, environment, and society. Our findings underscore prevalent methodologies such as computational modelling utilizing software suites like MATLAB/Simulink, HOMER, and others to derive empirical data. Additionally, parametric analyses emerge as the predominant approach, characterized by the application of algorithms such as Particle Swarm Optimization (PSO), Fuzzy Logic Control (FLC), and Genetic Algorithms (GA), among others. PV-wind hybrid energy systems are classified into autonomous and grid-interconnected configurations, with primary components comprising PV-wind generators. The anticipated trajectory suggests a burgeoning development of these hybrid energy harvesting systems, underpinned by their potential as clean, sustainable, and eco-friendly energy sources.

Enhancing solar thermoelectric power generation with supercritical CO2 cooling: Hydraulic, thermal, and exergy analysis

This research investigates the dynamic behavior and impact of various factors on the hydraulic, thermal, and exergetic characteristics of a solar-based thermoelectric device using a pin–fin heatsink cooled by supercritical CO2. A comprehensive numerical model analyzes the heat dissipation and performance of the power generator, integrating a thermoelectric generator and a pin–fin heatsink with various pin shapes. Key geometric and operational parameters, such as the height of PN (P-type and N-type semiconductor) legs of the TEG, the number of thermocouples, operating pressure, Reynolds number, and CO2 temperature, are examined for a comprehensive performance assessment. The study highlights the superior performance of CO2 coolant over traditional water-cooling system. Near the critical temperature of CO2, enhanced heat transfer significantly boosts power output, conversion efficiency, and exergetic efficiency. For example, at 8 MPa, the TEG’s (thermoelectric generator) power output increases from 1.31 mW at 295 K to 2.35 mW at 310 K. Comparisons reveal that while water coolant lowers the cold side temperature more effectively, it results in reduced power output due to decreased temperature differentials and increased pressure loss. Conversely, CO2 coolant maintains higher cold side temperatures while having advantages in power output. At 315 K, the cold side temperature with water is 315.7 K compared to 346.7 K with CO2. Increasing the number of thermocouples from 18 to 32 for a leg height of 1 mm leads to an approximate 102.3 % increase in voltage. Raising the PN leg height from 1 mm to 2 mm for an NTC of 50 results in a nearly 99.8 % increase in voltage. Lozenge-shaped fin produces a peak power output of 2.73 mW, while square fin generates 2.62 mW. This research underscores CO2’s potential as a high-performance coolant in solar thermoelectric applications, offering insights into optimizing system design for maximum efficiency.

A Review of CIGS Thin Film Semiconductor Deposition via Sputtering and Thermal Evaporation for Solar Cell Applications

Over the last two decades, thin film solar cell technology has made notable progress, presenting a competitive alternative to silicon-based solar counterparts. CIGS (CuIn1−xGaxSe2) solar cells, leveraging the tunable optoelectronic properties of the CIGS absorber layer, currently stand out with the highest power conversion efficiency among second-generation solar cells. Various deposition techniques, such as co-evaporation using Cu, In, Ga, and Se elemental sources, the sequential selenization/sulfidation of sputtered metallic precursors (Cu, In, and Ga), or non-vacuum methods involving the application of specialized inks onto a substrate followed by annealing, can be employed to form CIGS films as light absorbers. While co-evaporation demonstrates exceptional qualities in CIGS thin film production, challenges persist in controlling composition and scaling up the technology. On the other hand, magnetron sputtering techniques show promise in addressing these issues, with ongoing research emphasizing the adoption of simplified and safe manufacturing processes while maintaining high-quality CIGS film production. This review delves into the evolution of CIGS thin films for solar applications, specifically examining their development through physical vapor deposition methods including thermal evaporation and magnetron sputtering. The first section elucidates the structure and characteristics of CIGS-based solar cells, followed by an exploration of the challenges associated with employing solution-based deposition techniques for CIGS fabrication. The second part of this review focuses on the intricacies of controlling the properties of CIGS-absorbing materials deposited via various processes and the subsequent impact on energy conversion performance. This analysis extends to a detailed examination of the deposition processes involved in co-evaporation and magnetron sputtering, encompassing one-stage, two-stage, three-stage, one-step, and two-step methodologies. At the end, this review discusses the prospective next-generation strategies aimed at improving the performance of CIGS-based solar cells. This paper provides an overview of the present research state of CIGS solar cells, with an emphasis on deposition techniques, allowing for a better understanding of the relationship between CIGS thin film properties and solar cell efficiency. Thus, a roadmap for selecting the most appropriate deposition technique is created. By analyzing existing research, this review can assist researchers in this field in identifying gaps, which can then be used as inspiration for future research.

Structural, electronic, optical, and thermoelectric features of Rb2XSbX’6 (X= Ag, Cu; X’= Cl, Br): Ab-initio calculations

This study investigates the electronic, optical, and thermoelectric properties of lead-free double halide perovskite materials, Rb2XSbX'6, through first-principles calculations employing Density Functional Theory (DFT) and the Wien2k code, complemented by Boltzmann transport theory. By substituting X with Ag or Cu and X’ with Cl or Br in Rb2XSbX’6, we uncover interesting properties. Rb2AgSbBr6, Rb2AgSbCl6, Rb2CuSbCl6, and Rb2CuSbBr6 exhibit low indirect band gaps of 1.18 eV, 2.17 eV, 1.22 eV, and 0.87 eV, respectively, alongside high absorption in the visible region. The studied compounds sustained a high level of structural and thermodynamic stability, which was confirmed by their high bulk modulus and negative formation energy. Furthermore, extensive values were observed for the figure of merit in the thermoelectric study. Given the strong agreement with previous research, these findings position the investigated materials as promising candidates for visible-light solar cell device applications.