Solar Concentrator Research Articles

Experimental analysis of a solar interfacial evaporation under high power concentrator

Solar-driven interfacial evaporation in solar distillers is recently intensively investigated. This work presents a new distiller system based on bottom-heating/interfacial evaporation process driven by high power concentrated solar energy. This system applies Annual Fresnel solar concentration and a circular Fresnel lens, increasing input solar energy. The 1 D water supply wick is elected as the interfacial evaporator to satisfy water evaporation demand by capillary suction. Solar distillers with high-power concentrator are experimentally tested and the results are discussed in this work. This work aims at analyzing the bottom-heating/interfacial evaporation performance under concentrated sunlight. The concentration ratio of an Annual Fresnel solar concentration and a circular Fresnel lens is 62.4. Further optimization of the distiller is carried out according to the concentrators and low ambient temperature requirements of interfacial evaporation. Performances of different distillers are compared. The results show that, the cumulative freshwater productivity of the interfacial evaporation and bottom-heating distiller are 21.25 kg/(m2·day) and 15.98 kg/(m2·day), respectively. The maximum gain output ratio of the interfacial evaporation is 72.1%, higher than the bottom-heating distiller. The maximum temperature of interfacial evaporation surface is 81.53 C∘.

Scaling laws of Space Solar Power Satellite concentrator unit distortion model obtained by performance-driven separate similitude analysis method

The distortion model may arise due to the inability to isometrically scale the thickness dimensions when utilizing similitude theory to develop scaling laws for large-scale concentrator units in the Space Solar Power Satellite. Previous works to address the distortion model neglect its negative impacts and persistent limits, resulting in insufficient prediction accuracy for prototype. To obtain scaling laws of the distortion model, this paper introduces a novel strategy called the performance-dominated separate similitude analysis, which significantly reduces the distortion model's negative impacts and persistent limits on similitude prediction. Firstly, performance parameters sensitive to the distortion model are generated by dimensional analysis and the governing equation method. Secondly, the distortion model is separated into two scaled models: complete and partial similitude, based on the sensitive performance parameters. Subsequently, the scaling laws of complete and partial similitude models are derived, respectively. Finally, the scaling laws of the distortion model are derived by combining the complete and partial similitude laws. The proposed method is validated through finite element model simulation for both the concentrator unit prototype and the distortion model. Results indicate that in the best case, the prediction error doesn't exceed 0.2 %, and the prediction accuracy can be improved by up to 87.34 % compared to the existing methods.

Preliminary insights on the development of a continuous-flow solar system for the photocatalytic degradation of contaminants of emerging concern in water.

The ubiquity and impact of pharmaceuticals and pesticides, as well as their residues in environmental compartments, particularly in water, have raised human and environmental health concerns. This emphasizes the need of developing sustainable methods for their removal. Solar-driven photocatalytic degradation has emerged as a promising approach for the chemical decontamination of water, sparking intensive scientific research in this field. Advancements in photocatalytic materials have driven the need for solar reactors that efficiently integrate photocatalysts for real-world water treatment. This study reports preliminary results from the development and evaluation of a solar system for TiO2-based photocatalytic degradation of intermittently flowing water contaminated with doxycycline (DXC), sulfamethoxazole (SMX), dexamethasone (DXM), and carbendazim (CBZ). The system consisted of a Fresnel-type UV solar concentrator that focused on the opening and focal point of a parabolic trough concentrator, within which tubular quartz glass reactors were fixed. Concentric springs coated with TiO2, arranged one inside the other, were fixed inside the quartz reactors. The reactors are connected to a raw water tank at the inlet and a check valve at the outlet. Rotating wheels at the collector base enable solar tracking in two axes. The substances (SMX, DXC, and CBZ) were dissolved in dechlorinated tap water at a concentration of 1.0mg/L, except DXM (0.8mg/L). The water underwent sequential batch (~ 3 L each, without recirculation) processing with retention times of 15, 30, 60, 90, and 120min. After 15min, the degradation rates were as follows: DXC 87%, SMX 35.5%, DXM 32%, and CBZ 31.8%. The system processed 101 L of water daily, simultaneously removing 870, 355, 256, and 318µg/L of DXC, SMX, DXM, and CBZ, respectively, showcasing its potential for real-world chemical water decontamination application. Further enhancements that enable continuous-flow operation and integrate highly effective adsorbents and photocatalytic materials can significantly enhance system performance.

Highly efficient molybdenum nanostructures for solar thermophotovoltaic systems: One-step fabrication of absorber and design of selective emitter

Efficient solar energy harvesting materials or structures have become a topic of great interest in response to the ever-increasing energy demand. Refractory transition metals have been found to exhibit attractive properties in broadband absorptance, making them highly effective in solar thermophotovoltaic (STPV) systems that aim to surpass the Shockley-Queisser limit. Typically, broadband absorbers are made from hybrid materials or complex geometrical structures, which require multi-step fabrication technologies. In this study, we successfully developed a highly efficient broadband absorber based on molybdenum (Mo) nanosheets using a one-step physical vapor deposition process. The nanosheets result in the high absorber efficiencies of 96.1 % for blackbody radiation (BBR) at 5778 K and of 96.4 % for air mass (AM) 1.5 spectrum, and are insensitive to polarization and incident angle. After annealing at 1650 K for 24 h, the Mo nanosheets absorber demonstrates outstanding thermal stability without compromising the efficiency of the STPV system. To complete the STPV system, a selective narrowband Mo-based gratings emitter was further designed with a high emissivity of 96 % at a wavelength of 2.17 μm, resulting in a high PV cell efficiency of 41.8 % around 1723 K. Through a series of theoretical calculations, the proposed STPV system can achieve an overall conversion efficiency of 40.2 % by a trade-off between the structure temperature and the sun concentration. Furthermore, an efficiency of 35.5 % can be achieved at a low temperature of 1073 K with a low solar concentration of 500 suns.The results provide tremendous opportunities for widespread applications of high-performance STPV systems.

Heat input optimization for the ignition of self-sustained smoldering remediation of contaminated soils using concentrated solar power

In this paper, we explore the industrial-scale feasibility of using concentrated solar power (CSP) as the heat source in the smoldering remediation of petroleum-contaminated soil. Approximately 5 L soil samples were loaded in a narrow-channel reaction chamber and heated from the bottom with CSP to identify the required heat input to achieve ignition. Both petroleum and granular activated carbon (GAC) were used as combustible media. GAC was selected as a cleaner-burning alternative to petroleum and could emulate petroleum-contaminated soil at a mixture of 40 g GAC per kg pool sand on a 1.5 cm bed of GAC. This mixture of GAC showed robust ignition with a minimum power input of 240 W, which was slightly higher than the power input required to ignite industrially generated petroleum-contaminated soil. Preheat temperatures in excess of 300°C were achieved in most experiments, allowing for robust ignition of the smoldering remediation process. CSP was collected using parabolic reflectors 600 mm in diameter and was delivered to the reaction chamber with fiber optic bundles. Each solar concentrator delivered between 50 and 80 W to the reaction chamber, and four concentrators were required to reliably achieve the required power input.

The Emerging Star of Carbon Luminescent Materials: Exploring the Mysteries of the Nanolight of Carbon Dots for Optoelectronic Applications.

Carbon dots (CDs), a class of carbon-based nanomaterials with dimensions less than 10nm, have attracted significant interest since their discovery. They possess numerous excellent properties, such as tunability of photoluminescence, environmental friendliness, low cost, and multifunctional applications. Recently, a large number of reviews have emerged that provide overviews of their synthesis, properties, applications, and their composite functionalization. The application of CDs in the field of optoelectronics has also seen unprecedented development due to their excellent optical properties, but reviews of them in this field are relatively rare. With the idea of deepening and broadening the understanding of the applications of CDs in the field of optoelectronics, this review for the first time provides a detailed summary of their applications in the field of luminescent solar concentrators (LSCs), light-emitting diodes (LEDs), solar cells, and photodetectors. In addition, the definition, categories, and synthesis methods of CDs are briefly introduced. It is hoped that this review can bring scholars more and deeper understanding in the field of optoelectronic applications of CDs to further promote the practical applications of CDs.

A Multistate Thermoresponsive Smart Window Based on a Multifunctional Luminescent Solar Concentrator.

Conventional luminescent solar concentrators (LSCs) usually only have the ability to absorb solar energy and convert it to electricity but are not able to regulate the transmitted light. Herein, a multistate thermoresponsive smart window (SW) based on LSC has been fabricated, in which the stimuli-responsive host layer consists of polydimethylsiloxane (PDMS) and ethylene glycol solution (EGS) microdroplets stacking with LSC layer-based on near-infrared (NIR) CuInSe2-xSx/ZnS core/shell quantum dots (QDs) and PDMS matrix. As-synthesized CISSe/ZnS QDs with broad NIR absorption in LSC exhibit controllable emission spectra over 833-1088 nm and high photoluminescence (PL) quantum yield from 45 to 83%. Coupling with Si solar cells as a reference, optimized LSC-SW devices with dimensions of 5 × 5 × 0.9 cm3 exhibit higher power conversion efficiency (PCE) of 1.19-1.36% with increased temperature from 0 to 50 °C than those of sole LSC and SW devices. The corresponding visible light transmissions are regulated from 75.1 to 48.1% accordingly. The improvement of PCEs in an opaque state is mainly due to enhanced absorption of QDs originating from rescattered photons from the EGS/PDMS layer, leading to more emitted photons reaching photovoltaics. This work is expected to bring up new opportunities for applications in greenhouses, building facades, and energy-efficient smart windows.

Aplanatic solar concentrators for tubular absorbers.

A fundamentally new, to the best of our knowledge, class of linear (2D) dual-mirror aplanats tailored to tubular absorbers is developed for the types of solar concentrators used for thermal power. It is shown that prior investigation establishing this concept possesses unrecognized additional designs, as well as having missed high-performance configurations. It is shown that our line-focus solar concentrators can attain intercept factors exceeding 0.9 at concentration values as high as 55, with practical mirror contours and assemblies. Designed expressly for tubular absorbers, they represent improvements upon previous aplanatic concentrators that were tailored to flat one-sided absorbers but applied to tubular absorbers (as well as to conventional parabolic troughs).

Twisted helical Tape's impact on heat transfer and friction in zinc oxide (ZnO) nanofluids for solar water heaters: Biomedical insight

This study explores the influence of Zinc Oxide (ZnO) nanofluids on solar water heaters with Dimple Tubes and Helical Twisted Tape (DTHTT) surfaces. The helical twisted tape design enhances turbulence, improving nanofluid mixing and thermal exchange. Computational fluid dynamics (CFD) validates the efficiency of the parabolic trough solar water heater (PTSWH) with emphasis on solar light concentration and feed water flow velocity. Optimal conditions include a 0.3% ZnO nanofluid volume concentration, mass flow rates between 1.0 kg/min and 5.0 kg/min, and copper-type twisted helical tapes. Experimental results reveal Nusselt number enhancements of 15.1% and 20.96% at H/D = 10, and 16.72% and 32.12% at H/D = 3, for 0.3% ZnO nanofluid, at Reynolds numbers from 3000 to 8000. The twisted tape arrangement at H/D = 3 exhibits increased fluid mixing, leading to higher convective heat transfer. Friction factor enhancements at Reynolds numbers 3000 and 8000 are 0.26% and 0.38%, respectively, compared to the base fluid. At a 3.0 kg/min mass flow rate, thermal efficiency increases to 39.25%, a 13.25% gain over plain tapes. The model shows a ±3.24% deviation from the expected friction factor, with a total ±1.2% discrepancy between experimental and simulated findings, remaining within an acceptable range.

Luminescent Solar Concentrator with Advanced Structure for Reabsorption Loss Suppression and Synergistic Energy Harvesting

AbstractAs large‐area and optically transparent photon harvesting devices, luminescent solar concentrators (LSCs) are promising candidates for building‐integrated photovoltaics owing to their high transmittance and resistance to shadowing effects existing in solar cells. Up to now, there are still many challenges in the practical application of LSCs: 1) Reabsorption loss is inevitable during photoluminescence transmission due to indirect illumination of solar cells in LSC system. 2) Satisfactory energy harvesting cannot be achieved in rainy conditions due to the substantial attenuation of the incident light intensity. 3) Evaporation residue on the surface of LSCs leads to device performance degradation. Pioneering researches and feasible strategies for reabsorption loss suppression, energy harvesting in rainy days as well as self‐cleaning property are still lacking demonstration. In this work, reabsorption loss is suppressed based on advanced structural LSCs with universally applicable optical spacer layer. Then the integrated LSCs with droplet‐based electricity generator (DEG) are proposed for the first time. Such DEG‐LSCs not only realize synergistic harvesting of solar and raindrop energy, but also possess self‐cleaning properties. Finally, a self‐powered temperature and humidity sensing system is designed and demonstrated to provide feasible ideas for the practical application of DEG‐LSCs in self‐powered intelligent buildings.

Advancing Solar Rooftop Power Generation: A Review on the Integration of Concentrated Solar Technology and Advanced Materials with Economic Perspectives

Abstract: This review paper offers a thorough analysis of the integration of concentrated solar technology and advanced materials in solar rooftop power generation, with a primary emphasis on optimizing efficiency and economic viability. As the demand for sustainable energy solutions intensifies, harnessing concentrated solar energy on rooftops presents a promising avenue for meeting these challenges. The paper explores current advancements in concentrated solar technologies, including solar concentrators, parabolic troughs, and solar towers, elucidating their working principles and efficiency gains. Concurrently, the integration of advanced materials, such as high-efficiency photovoltaic materials, thermal storage materials, and coatings, is discussed for their role in enhancing the overall performance and durability of rooftop solar systems. A critical examination of the economic aspects associated with these technologies forms a pivotal aspect of this review, encompassing an evaluation of initial investment costs, operational expenses, and potential returns on investment. Economic models and case studies are presented, offering valuable insights into the financial implications and feasibility of widespread adoption.

Experimental investigation of hybrid vacuum tube solar water heater/parabolic concentrator integrated with phase change material and nanofluid as HTF simultaneously; energy and exergy assessments

ABSTRACT Solar water heaters suffer from fluctuating hot water production due to unpredictable weather changes throughout the day. In this study, the hybrid configuration of a vacuum tube solar water heater with a parabolic solar concentrator, in conjunction with the application of paraffin as a phase change material, is employed as a novel approach to address this problem. Furthermore, the study investigates the utilisation of a nanofluid (0.05%, 0.1%, and 0.2% mass) containing Al2O3 and ZnO nanoparticles dispersed in water-ethylene glycol (base fluid) as the medium fluid to enhance thermal performance. The experimental results revealed that the utilisation of 0.2% mass ZnO and Al2O3 nanofluids led to a considerable increase of 10.74% and 7.25%, respectively, in the maximum reservoir temperature. This resulted in a respective average thermal efficiency improvement of 41.6% and 33.9% compared to the base fluid. Furthermore, the maximum exergy efficiency of the system exhibited a significant increment of 54% and 40.1% compared to the base fluid. Moreover, the incorporation of phase change material in the system effectively minimised temperature fluctuations.

Simulation and Performance Analysis of Six Types of Sun Tracker Approaches: A Comparative Analysis for Solar Concentrating Technology Application at Burkina Faso

Simulation and Performance Analysis of Six Types of Sun Tracker Approaches: A Comparative Analysis for Solar Concentrating Technology Application at Burkina Faso

Molecular dynamics investigation of ionanofluids (INFs): Towards a deeper understanding of their thermophysical, structural and dynamical properties

Ionanofluids (INFs) are a novel type of heat transfer fluids consisting of fine nanoparticles suspended in ionic liquids (ILs). They exhibit improved thermal properties, including enhanced thermal conductivity, non-volatility, and non-flammability, making them ideal candidates for various applications, especially solar concentrators. In this work, for the first time, molecular dynamics (MD) simulations are used to investigate the thermophysical, structural, and dynamical properties of a specific INF composed of the [HMIM][BF4] IL and SiC nanoparticles in the temperature range of 298.15–338.15 K and at different nanoparticle volume fractions, i.e. 1.10 %, 2.27 %, and 3.47 %. Radial distribution functions (RDFs) revealed a strong structural correlation between the fluorine atoms of anion and the HR atom of the cation ring and also with the carbon and silicon atoms of the nanoparticle. The results showed that with increasing the volume fraction of nanoparticles, ions tend to have more interactions with nanoparticles, and the interactions between the anions and cations decrease. As a result, the thermal conductivity, viscosity, and density of ions in the INF increases. Finally, we made some comparisons between the simulated thermal conductivities and viscosities of the studied INF with classical models. The results showed that, in some cases, the simulation results were even better than some models compared to the experimental values. The insights obtained from this study not only enhance our understanding of the structure and dynamic behavior of the INF, but also can contribute to the development of innovative materials and more efficient solar thermal systems.

A Study on the Optical Efficiency of Solar Concentrators Based on Ray Tracing Method

A Study on the Optical Efficiency of Solar Concentrators Based on Ray Tracing Method

Nanomaterial Mixed with Dyes to Make Solar Cell Concentrator

In the present work, different concentrations of natural dyes (pomegranate, saffron, black lemon) were prepared by solving (0.001,0.002,0.003) g from these dyes in 100ml of pure water. The preparation of different concentrations mixed with the nanomaterial (titanium oxide) at a rate of 0.9 grams per 100 ml of pure water, in addition to mixing it with polymer epoxy resin at a ratio of 2:1 to obtain a solid mold after leaving it for two days to dry, and four solar cells were placed on the four different of the blocks which manufacture as solar cell concentrator. The best value for the efficiency of the solar cell was found for the pomegranate dye with a concentration of 0.002 grams, which is (ƞ=1.232), while the efficiency of the solar cell without dye is (ƞ=0.500).

Evidence of hot carrier extraction in metal halide perovskite solar cells

AbstractThe presence of hot carriers is presented in the operational properties of an (FA,Cs)Pb(I, Br, Cl)3 solar cell at ambient temperatures and under practical solar concentration. Albeit, in a device architecture that is not suitably designed as a functional hot carrier solar cell. At 100 K, clear evidence of hot carriers is observed in both the high energy tail of the photoluminescence spectra and from the appearance of a nonequilibrium photocurrent at higher fluence in light J–V measurements. At room temperature, however, the presence of hot carriers in the emission at elevated laser fluence is shown to compete with a gradual red shift in the PL peak energy as photoinduced halide segregation begins to occur at higher lattice temperature. The effects of thermionic emission of hot carriers and the presence of a nonequilibrium carrier distribution are also shown to be distinct from simple lattice heating. This results in large unsaturated photocurrents at high powers as the Fermi distribution exceeds that of the heterointerface controlling carrier transport and rectification.

Quantitative assessment of the scale conversion from instantaneous to daily GPP under various sky conditions based on MODIS local overpassing time

ABSTRACT With the increasing frequency of extreme events, daily gross primary productivity (GPP) is necessary to be accurately assessed to determine when and how much it is affected. Fluctuating environmental conditions contribute to diverse diurnal photosynthetic patterns influenced by changing atmospheric factors, including solar radiation, CO2 concentrations, and leaf temperature. This complexity underscores the challenge of accurately estimating daily GPP. We quantitatively assessed three temporal upscaling approaches – cosine of the solar zenith angle, extraterrestrial solar irradiance, and photosynthetic active radiation(PAR) – under varying sky conditions. Additionally, we introduced a novel correction method for universal temporal upscaling ratios. Instantaneous GPP values from the FLUXNET2015 dataset, acquired around the MODIS overpassing time, were utilized. The upscaled daily GPP exhibited minimal deviation from the half-hourly GPPs collected between 11 am and 1 pm, with increased discrepancies for GPPs later in the afternoon. The PAR-based approach demonstrated superior accuracy in the afternoon, effectively capturing incoming radiation changes due to clouds. Instant environmental variables-GPP relationships were weak under clear skies but exhibited moderate-to-high positive correlations under cloudy conditions. Analyzing the impact of the diffuse ratio of incoming photosynthetic active radiation on instantaneous GPP revealed limited enhancement at short time scales. On a daily scale, all three temporal upscaling approaches, under different ranges of clearness index, consistently underestimated daily GPP. We proposed a novel correction method, normalizing the difference between maximum and minimum air temperature in a day, notably reduced errors by approximately 10.69 and 21.07 gC m−2 d−1 for cosine of the solar zenith angle and extraterrestrial solar irradiance-based temporal upscaling approaches. We recommend adopting the corrected temporal upscaling factor globally due to its simplicity and improved accuracy.

Predicting the efficiency of luminescent solar concentrators for solar energy harvesting using machine learning

Building-integrated photovoltaics (BIPV) is an emerging technology in the solar energy field. It involves using luminescent solar concentrators to convert traditional windows into energy generators by utilizing light harvesting and conversion materials. This study investigates the application of machine learning (ML) to advance the fundamental understanding of optical material design. By leveraging accessible photoluminescent measurements, ML models estimate optical properties, streamlining the process of developing novel materials, offering a cost-effective and efficient alternative to traditional methods, and facilitating the selection of competitive materials. Regression and clustering methods were used to estimate the optical conversion efficiency and power conversion efficiency. The regression models achieved a Mean Absolute Error (MAE) of 10%, which demonstrates accuracy within a 10% range of possible values. Both regression and clustering models showed high agreement, with a minimal MAE of 7%, highlighting the efficacy of ML in predicting optical properties of luminescent materials for BIPV.

Processing and optical behavior of dense (Hf,Zr)B2 solid solutions for solar energy receivers

While individual borides and, more recently, quinary High Entropy Transition Metal Borides have been investigated, the fabrication and characterization of bulk binary to quaternary solid solutions are barely explored. In this work, dense (Hf0.5Zr0.5)B2 is produced by Spark Plasma Sintering (SPS) from powders prepared by Self-propagating High-temperature (SHS). SHS produced a multiphase product, whose secondary phases are fully converted into the desired diborides during the subsequent SPS step. Optical properties of (Hf0.5Zr0.5)B2 are evaluated for the first time with focus on the possible use as novel high-temperature solar thermal absorber, by hemispherical reflectance measurements and calculation of solar absorptance, temperature-dependent spectral selectivity and absorber opto-thermal efficiency at various solar concentration ratios. To optimize the material, a chemically etched surface texture was realized to modify the optical properties. The etched sample showed a higher solar absorptance (0.71) and a lower spectral selectivity than the unetched one, with consequent higher opto-thermal efficiency at all temperatures for solar concentration ratios 1000 ÷ 3000, while at lower concentration ratios and temperatures >1400 ÷ 1600 K, the unetched sample shows the highest efficiency. These results show the promising properties of binary diborides for solar thermal applications.