Solar Energy Capture Research Articles

Optimizing thermal properties and heat transfer in 3D biochar-embedded organic phase change materials for thermal energy storage

Enhancing the thermal properties and light-absorbing capabilities of phase change materials (PCMs) through the utilization of environmentally friendly, economically viable biochar materials is pivotal for optimizing solar energy capture and utilization. Herewith, initially, a green, three-dimensional, eco-friendly carbon nano inclusion is synthesized from Prosopis juliflora through vacuum oven carbonization at 130 °C, followed by size reduction via ball milling, promising high-impact contributions. Subsequently, green-synthesized nano-inclusions are dispersed in PEG-1000, creating advanced nano-enhanced phase change materials with improved thermo-physical properties using a two-step ultrasonication technique for enhanced thermal conductivity. This innovative study comprehensively explores the morphological behaviour, chemical stability, optical absorptivity, thermal properties, and reliability of the PEG-PJ composite. Remarkably, present research revealed that the composite achieved its highest thermal conductivity, an impressive 0.49 W/m⋅K, at 0.7 wt% of 3-D (PJ) biochar. Notably, the melting temperatures of the PEG-PJ composites consistently ranged from 40.1 °C to 40.5 °C. At the same time, their latent heat capacities displayed a notable increase, ranging from 145 J/g to 152.7 J/g, marking a substantial enhancement of 3.968% and 1.758%, respectively. Furthermore, to confirm the reliability and consistency of experimental findings, 500 thermal cycles were performed. Additionally, a numerical analysis study is conducted by utilizing 2-D energy modelling software to simulate the heat transfer rate owing to the improved thermal conductivity of the developed PEG-PJ composite PCM compared to PEG-1000. In conclusion, developed composites optimize solar storage, improve building thermal control, and enhance industrial heat exchangers for sustainable innovation in energy.

Effect of porous layer and initial salt gradient on improving SGSP stability: Transient numerical simulation and theoretical analysis

The salt gradient solar pond (SGSP) is a low-cost and large-scale solar energy capture and storage device. The stability of the non-convective zone (NCZ) is critical for the well-functioning and efficiency of SGSP. To understand when and how SGSP lost its effectiveness, the turbulent double-diffusive convection in solar ponds was first solved numerically with a Large Eddy Simulations (LES) model. The simulations show that attaching a porous layer or increasing the initial salt concentration effectively delays the destruction of NCZ. By increasing the initial salt concentration from 5.2% to 20.8%, the destruction time increases from 7 to 22 h. By attaching a porous layer, the overturn time can increase by about 8 h, resulting in a temperature rise from 46 °C to 73 °C in the storage layer. The flow field analysis shows that both interface erosion and turbulent mixing in NCZ cause the destruction of NCZ. The stability analysis shows that the turbulent mixing decreases the salinity gradient in NCZ, making it more susceptible to erosion. By inhibiting the turbulent mixing, the porous layer at the bottom can effectively delay the arrival of NCZ destruction. Thus, the heat storage capacity and stability of solar ponds are enhanced.

Central Tower Solar Receiver Structures: Construction and Performance Comparison”

The purpose of this study is to evaluate the design and thermal performance of various configurations of central tower solar receivers, with an emphasis on spiral tube receivers. Specifically, it addresses the challenges of cost-effectiveness and efficiency within Concentrating Solar Power (CSP) systems. Multiple designs are assessed using a combination of analytical models and computational fluid dynamics (CFD) tools to assess thermal efficiency, heat transfer, and convective losses. Spiral tube receivers demonstrate superior thermal characteristics across various metrics as a result of the grid independence tests. Additionally, we discuss the effects of various mass flow rates on the outlet temperatures of the heat transfer fluid (HTF), in order to improve solar energy capture and conversion by optimizing the receivers.

Rational design and performance prediction of organic photosensitizer based on TATA+ dye for hydrogen production by photocatalytic decomposition of water.

In comparison to metal complexes, organic photosensitive dyes employed in photocatalytic hydrogen production exhibit promising developmental prospects. Utilizing the organic dye molecule TA+0 as the foundational structure, a series of innovative organic dyes, denoted as TA1-1 to TA2-6, were systematically designed. Employing first-principles calculations, we methodically explored the modifying effects of diverse electron-donating groups on the R1 and R2 positions to assess their application potential. Our findings reveal that, relative to the experimentally synthesized TATA+03, the TA2-6 molecule boasts a spatial structure conducive to intramolecular electron transfer, showcasing the most negative reduction potential (Ered = -2.11eV) and the maximum reaction driving force (△G0 2 = -1.26eV). This configuration enhances its compatibility with the reduction catalyst, thereby facilitating efficient hydrogen evolution. The TA2-6 dye demonstrates outstanding photophysical properties and a robust solar energy capture capacity. Its maximum molar extinction coefficient (ε) stands at 2.616 × 104M-1·cm-1, representing a remarkable 292.8% improvement over TATA+03. In conclusion, this research underscores the promising potential of the TA2-6 dye as an innovative organic photosensitizer, positioning it as an efficacious component in homogeneous photocatalytic systems.

The Dust Planet Clarified Modelling Martian MY29 Atmospheric Data Using the Dynamic-Atmosphere Energy-Transport (DAET) Climate Model

The Dynamic Atmosphere Energy Transport (DAET) climate model, a mathematical model previously applied to a study of Earth’s climate, has been adapted to study the climatic features in the low-pressure, dust-prone atmosphere of the planet Mars. Using satellite data observed for Martian Year 29 (MY29), temperature profiles are presented here thatconfirm the studies of prior authors of the existence on Mars of a tropical solar-energy driven zone of daytime atmospheric warming, that both diurnally lifts the tropopause and follows the annual latitudinal cycle of the solar zenith. This tropical limb of ascending convection is dynamically linked to polar zones of descending air, the seasonal focus of which is concentrated over each respective hemisphere’s polar winter cap of continuous darkness. An analysis of the MY29 temperature data was performed to generate an annual average surface temperature metric that was then used to both inform the design of and to constrain the computation of the DAET climate model. The modelling analysis suggests that the Martian atmosphere is fully transparent to surface emitted thermal radiant energy. The role of lit hemisphere surface reflectance provides an energy boost to the dust-prone surface boundary layer at grazing-angle latitudes. This backlighting process of quenched solar energy capture ensures that the Martian climate operates as a black-body system. The high emissivity solar illuminated hemispheric surface heats the atmosphere by direct thermal conduction followed by a process of adiabatic convection across the planetary surface. It is the non-lossy process of adiabatic convection that results in the development and maintenance of a flux-enhanced atmospheric energy reservoir which accounts for the 2 Kelvin Atmospheric Thermal Effect in the Martian troposphere.

Intelligent photovoltaic system to maximize the capture of solar energy

The large consumption of electricity worldwide has an impact on the environment which can be said to alter climate change, the degradation of the ozone layer and acid rain. A house has an average daily consumption of 270kWh, this is why solar panels are very useful and can help to have a renewable energy at low costs. To create an intelligent photovoltaic system, different electronic sensors can be applied to follow the sunlight through a series of instructions in some programming software. The article proposes to prototype an intelligent photovoltaic system, based on artificial intelligence with a neural network library "propet" having a positive impact on the optimization of power generation by allowing a more accurate tracking of the sun and a greater collection of photovoltaic energy throughout the day. performing an integration between Arduino and machine learning algorithms such as artificial neural networks in prediction of time series. Different practical experiments were performed to illustrate the effectiveness of the proposed method.

One-Step Dry Coating of Hybrid ZnO-WO3 Nanosheet Photoanodes for Photoelectrochemical Water Splitting with Composition-Dependent Performance.

In this study, the potential of zinc oxide (ZnO), tungsten oxide (WO3), and their composites (ZnO-WO3) as photoanodes for photoelectrochemical (PEC) water splitting was investigated. ZnO-WO3 nanocomposites (NCs) were deposited on fluorine-doped tin oxide substrates at room temperature using a one-step dry coating process, the nanoparticle deposition system, with no post-processes. Different compositions of ZnO-WO3 NCs were optimized to enhance the kinetics of the PEC water-splitting reaction. Surface morphology analysis revealed the transformation of microsized particle nanosheets (NS) powder into nanosized particle nanosheets (NS) across all photoanodes. The optical characteristics of ZnO-WO3 photoanodes were scrutinized using diffuse reflectance and photoluminescence emission spectroscopy. Of all the hybrid photoanodes tested, the photoanode containing 10 wt.% WO3 exhibited the lowest bandgap of 3.20 eV and the lowest emission intensity, indicating an enhanced separation of photogenerated carriers and solar energy capture. The photoelectrochemical results showed a 10% increase in the photocurrent with increasing WO3 content in ZnO-WO3 NCs, which is attributed to improved charge transfer kinetics and carrier segregation. The maximum photocurrent for a NC, i.e., 10 wt.% WO3, was recorded at 0.133 mA·cm-2 at 1.23V vs. a reversible hydrogen electrode (RHE). The observed improvement in photocurrent was nearly 22 times higher than pure WO3 nanosheets and 7.3 times more than that of pure ZnO nanosheets, indicating the composition-dependence of PEC performance, where the synergy requirement strongly relies on utilizing the optimal ZnO-WO3 ratio in the hybrid NCs.

Thermal energy storage characteristics of carbon-based phase change composites for photo-thermal conversion

Capture and utilization of solar energy using phase change materials (PCMs) can effectively answer the challenge of solar intermittency. However, the flaws of low thermal conductivity and poor thermal stability of PCMs limit their practical applications, and the selective absorption of solar energy also hinders it to achieve high photo-thermal conversion. In this work, a novel PCM was synthesized by adding expanded graphite and olefin block copolymers blended within paraffin wax. Enhanced thermal conductivities were realized that a 17.12 W/(m·K) in the vertical compression direction and 4.71 W/(m·K) in the parallel compression direction, which were 68.48 and 18.84 times in contrast to that of raw paraffin wax. A maximum solar absorptance of 97.47 % was achieved, and the photo-thermal conversion and energy storage capacity in the vertical compression direction were superior using the novel PCM. With the increase in light intensity, this PCM completed phase transition faster, reached a higher equilibrium temperature, and exhibited an outstanding thermal stability and cyclic stability within the assisted electron conductivity. Additionally, commercial software was also used to simulate thermoelectric applications of the PCM in real-world settings. This study provides new ideas for preparation and solar-thermal applications of anisotropic carbon-based PCMs.

Kinetic modeling identifies targets for engineering improved photosynthetic efficiency in potato (Solanum tuberosum cv. Solara).

Potato (Solanum tuberosum) is a significant non-grain food crop in terms of global production. However, its yield potential might be raised by identifying means to release bottlenecks within photosynthetic metabolism, from the capture of solar energy to the synthesis of carbohydrates. Recently, engineered increases in photosynthetic rates in other crops have been directly related to increased yield - how might such increases be achieved in potato? To answer this question, we derived the photosynthetic parameters Vcmax and Jmax to calibrate a kinetic model of leaf metabolism (e-Photosynthesis) for potato. This model was then used to simulate the impact of manipulating the expression of genes and their protein products on carbon assimilation rates in silico through optimizing resource investment among 23 photosynthetic enzymes, predicting increases in photosynthetic CO2 uptake of up to 67%. However, this number of manipulations would not be practical with current technologies. Given a limited practical number of manipulations, the optimization indicated that an increase in amounts of three enzymes - Rubisco, FBP aldolase, and SBPase - would increase net assimilation. Increasing these alone to the levels predicted necessary for optimization increased photosynthetic rate by 28% in potato.

Synergy of radical and nonradical degradations triggered by self-floating MnO2/cotton hydrogels with photothermal effect and oxygen vacancy

Persulfate-based advanced oxidation process is a promising technology for the water purification. While the synergy of radical and nonradical degradations are still unfeasible during persulfate activation, which process consumes a large amount of external energy. The self-floating manganese dioxide (MnO2)/cotton hydrogels (MCH) was developed, which achieves solar energy capture and wastewater treatment. In this study, a meticulously designed MCH enables simultaneous interface heating and persulfate activation. The MCH exhibited an excellent photothermal conversion capability with an evaporation rate of 2.89 kg/(m2·h) under 1 sun. The MCH coupled with peroxydisulfate (PDS) achieved a tetracycline (TC) degradation efficiency of 74.53 % under a visible light irradiation in 120 min. Furthermore, the result of TC evaporation experiment showed that 99.43 % of TC can be removed from the evaporated water. Interestingly, it was found that the singlet oxygen (1O2) increased with the concentration of Vo in the MCH during PDS activation process. In contrast to the conventional view, the thermal effect increases the concentration of Vo thus promoting the conversion of superoxide radicals (O2−) to 1O2 in the presence of Mn4+. Additionally, the polyvinyl alcohol/polyvinylpyrrolidone (PVA/PVP) hydrogel with porous structure that provided the oxygen for MnO2, promoting the production of reactive oxygen species. This study provides a new model for simultaneous evaporation and degradation, which deepens the understanding of synergy of radical and nonradical degradations.

Nanoarchitectonics of shape-stable composite phase change membrane based on multi-walled hollow microspheres for light-to thermal conversion

The development of shape-stable composite phase change materials (CPCMs) with outstanding light absorption and light-to thermal conversion performance is of great significant for harvesting and converting solar energy. Herein, we proposed a novel shape-stable composite phase change membrane based on multi-shelled hollow spheres (MHS) via a facile method. The MHS was fabricated by hydrothermal reaction and calcination treatment, and membrane was directly coated on glass plates after bonding the MHS. The as-resulted membranes possess excellent tensile strength, superior light absorption and light-to thermal conversion efficiency. The tensile strength of the membrane based MHS loaded 1-Hexadecylamine (HDA) can reach to 1.01 MPa. The light absorption of the membrane is about 93% under 1sun irradiation, and the photothermal conversion efficiency of the membrane is 81.4%. Moreover, the electro-to thermal conversion and heat dissipation of the membrane based CPCM were investigated. The results demonstrate that this membrane-based CPCM can not only be applied in solar energy capture, storage and conversion, but also has the prospect of being applied in the fields of electro-to thermal conversion and heat dissipation.

Design of an Automated System to Optimize the Capture of Solar Energy in Photovoltaic Panels

Design of an Automated System to Optimize the Capture of Solar Energy in Photovoltaic Panels

Chitosan incorporation for improving the dimensional stability of PLA aerogel encapsulated phase change materials

Chitosan (CH) was utilized to improve the shape stability and load resistance of Polylactic acid (PLA) aerogel encapsulated PCM during phase change. Specifically, PLA aerogel with high porosity (>90 %) was prepared first, and then soaked in ethanol and subsequently CH solution, to functionalize PLA aerogel. The aerogel is used to encapsulate paraffin to obtain a shape-stable bio-based PCM. We conduct a comprehensive analysis of its anti-leakage, shape stability, and phase transition properties. The results showed that the CH-modified PCM kept a high latent heat (169.5 J/g), maintained excellent anti-leakage performance, had stronger resistance to deformation in molten state, and improved anti-leakage performance under load. Combining the convenience and environmental protection of material preparation and modification, and the excellent performance of final PCM, this material is expected to be practically applied in building temperature regulation and solar energy capture.

Temporal performance indicators for an integrated pilot-scale membrane distillation-concentrated solar power/photovoltaic system

Management of concentrate streams in inland applications has uncertain long-term environmental impacts. This study investigates an intensified solar-energy capture desalination system that integrates membrane distillation (MD) with a hybrid concentrated solar power (CSP)/photovoltaic (PV) collector to realize self-sustained zero-waste discharge for effective management of concentrate streams in inland and off-grid applications. The demonstration-scale CSP/PV system can produce up to 178 kWh of thermal energy and 4 kWh of electrical energy per day. The thermal and electrical energy from the CSP/PV system is directly supplied to the air gap MD (AGMD) pilot-scale system producing up to 288 L of distilled water per day. Experiments were performed on the hybrid AGMD-CSP/PV system to evaluate system performance under various operating conditions including AGMD and CSP flow rates, CSP system pre-heating, and AGMD vacuum pressure. Experimental results indicate that doubling the AGMD flow rate results in a 119% increase in thermal energy utilization and a 71% increase in distillate production. Compared to the winter months, operating the system in summer months when direct normal irradiance (DNI) is highest results in nearly double the distillate production (88 L in winter and 168 L in summer) and nearly three times the amount of thermal energy consumption (15 kWh in winter and 43 kWh in summer). Operating with vacuum resulted in a 34% increase in distillate production and allowing the thermal storage reservoir to preheat in the winter resulted in a 61% increase in distillate production. Overall, experimental results highlight the tradeoff between distillate production and thermal and electrical energy production and consumption under various environmental conditions and the potential for AGMD-CSP/PV to be a stand-alone desalination system.

Spatially Resolved Optical Efficiency Measurements of Luminescent Solar Concentrators.

Luminescent solar concentrators (LSCs) are able to concentrate both direct and diffuse solar radiation, and this ability has led to great interest in using them to improve solar energy capture when coupled to traditional photovoltaics (PV). In principle, a large-area LSC could concentrate light onto a much smaller area of PV, thus reducing costs or enabling new architectures. However, LSCs suffer from various optical losses which are hard to quantify using simple measurements of power conversion efficiency. Here, we show that spatially resolved photoluminescence quantum efficiency measurements on large-area LSCs can be used to resolve various loss processes such as out-coupling, self-absorption via emitters, and self-absorption from the LSC matrix. Further, these measurements allow for the extrapolation of device performance to arbitrarily large LSCs. Our results provide insight into the optimization of optical properties and guide the design of future LSCs for improved solar energy capture.

Multi-mode resonance plasmonic solar absorber based on pyramid multiary-grating

In the manuscript, a broad-band perfect absorber based on multilayer-grating and MDM film structure is proposed and numerically studied. Finite difference time domain (FDTD) simulations indicate the absorption performances are originated from Fabry–Perot (FP) resonance effect, localized, and propagating surface plasmons (LSPs and PSPs) effect. The designed absorber possesses over 95% absorption from 697 nm to 2906 nm, and an average absorption of 98.7% is achieved with TM-polarized. For TM-polarized, the designed absorber possesses over 95% between 534 nm and 2475 nm when the oblique-angle is up to 45°, while for a TE-polarized light, the corresponding average absorption remains 80.48% when the oblique-angle is up to 30°. The average absorption is larger than 94% in different environment refractive indexes (1 < RI < 1.5), which illustrates the designed absorber possesses excellent environment RI stability. Another absorber with triple layer grating of different sizes is also designed, and the absorber has more than 95% absorption between 400 nm and 2376 nm, based on the high absorption and waveband, the absorber can find potential applications in solar energy capture. It is believed the proposed work can be applied in plasmonic solar absorber design, thermal emitter, and plasmonic imaging.

Direct solar-thermal scalable-decomposition of methanol flowing through a nanoparticle-packed bed reactor under outdoor environment

Using nanoparticles to absorb sunlight and drive methanol decomposition is a potential approach of solar energy utilization, which can convert solar energy into chemical energy of syngas. But a challenge of nanoparticle solar methanol decomposition is how to design concise and efficient large-scale application method. Focusing on the key issues of energy conversion and reaction system optimization, this work analyzes the sunlight capture, flow heat transfer and catalytic reaction in the nanoparticle volumetric absorption solar methanol decomposition system by theoretical and experimental studies. And the applied scalable solar-chemical system is constructed. The results show that the reaction bed constructed by nanoparticles has advanced solar energy capture performance, and can effectively drive the methanol decomposition. Compared with the traditional system, it has the lower solar concentration ratio of 17.5 and the higher energy conversion efficiency of 35.5%, and the reaction can be started up at the temperature of 136 °C. The cumulative solar-to-fuel energy conversion in this work can reach 1.3 × 1011 J/m2 in one year of operation in Nanjing, China. This work can further guide the construction of solar-driven thermochemical systems of splitting methanol into syngas and storing solar energy.

Unveiling the Synergy of Interfacial Contact and Defects in α‐Fe2O3 for Enhanced Photo‐Electrochemical Water Splitting

AbstractPhoto‐electrochemical (PEC) water splitting is a promising method for converting solar energy into clean energy, but the mechanism of improving PEC efficiency through the interfacial contact and defect strategy remains highly controversial. Herein, reduced graphene oxide (rGO) and oxygen vacancies are introduced into α‐Fe2O3 nanorod (NR) arrays using a simple spin‐coating method and acid treatment. The resultant oxygen vacancy–α‐Fe2O3/rGO‐integrated system exhibits a higher photocurrent, four times than the pristine α‐Fe2O3. It is well evidenced that the electronic interface interaction between α‐Fe2O3 and rGO is boosted with the oxygen vacancies, facilitating electron transfer from α‐Fe2O3 to rGO. Moreover, the oxygen vacancies not only create interband states in α‐Fe2O3 that can trap photogenerated holes and thus facilitate charge separation but significantly also strengthen the adsorption of oxidative intermediates and reduce the energy barrier of rate‐determining step during oxygen evolution reaction (OER). This study demonstrates an rGO–oxygen vacancy synergistic interfacial contact and defect modification approach to design semiconducting photocatalysts for high‐efficiency solar energy capture and conversion. The generated principle is expected to be extendable to another material system.

Antenna Modification in a Fast-Growing Cyanobacterium Synechococcus elongatus UTEX 2973 Leads to Improved Efficiency and Carbon-Neutral Productivity.

Our planet is sustained by sunlight, the primary energy source made accessible to all life forms by photoautotrophs. Photoautotrophs are equipped with light-harvesting complexes (LHCs) that enable efficient capture of solar energy, particularly when light is limiting. However, under high light, LHCs can harvest photons in excess of the utilization capacity of cells, causing photodamage. This damaging effect is most evident when there is a disparity between the amount of light harvested and carbon available. Cells strive to circumvent this problem by dynamically adjusting the antenna structure in response to the changing light signals, a process known to be energetically expensive. Much emphasis has been laid on elucidating the relationship between antenna size and photosynthetic efficiency and identifying strategies to synthetically modify antennae for optimal light capture. Our study is an effort in this direction and investigates the possibility of modifying phycobilisomes, the LHCs present in cyanobacteria, the simplest of photoautotrophs. We systematically truncate the phycobilisomes of Synechococcus elongatus UTEX 2973, a widely studied, fast-growing model cyanobacterium and demonstrate that partial truncation of its antenna can lead to a growth advantage of up to 36% compared to the wild type and an increase in sucrose titer of up to 22%. In contrast, targeted deletion of the linker protein which connects the first phycocyanin rod to the core proved detrimental, indicating that the core alone is not enough, and it is essential to maintain a minimal rod-core structure for efficient light harvest and strain fitness. IMPORTANCE Light energy is essential for the existence of life on this planet, and only photosynthetic organisms, equipped with light-harvesting antenna protein complexes, can capture this energy, making it readily accessible to all other life forms. However, these light-harvesting antennae are not designed to function optimally under extreme high light, a condition which can cause photodamage and significantly reduce photosynthetic productivity. In this study, we attempt to assess the optimal antenna structure for a fast-growing, high-light tolerant photosynthetic microbe with the goal of improving its productivity. Our findings provide concrete evidence that although the antenna complex is essential, antenna modification is a viable strategy to maximize strain performance under controlled growth conditions. This understanding can also be translated into identifying avenues to improve light harvesting efficiency in higher photoautotrophs.

Optimal planning for distributed energy systems with carbon capture: Towards clean, economic, independent prosumers

A low-carbon distributed energy system integrated with solar energy and natural gas-based carbon capture has been developed and analyzed. Considering the environment, economy, and independence, a novel multi-objective planning framework combining three methods has been employed to rationalize the capacity allocation and synergetic scheduling. A real energy-consuming park with multiple loads was taken as a case for hourly simulation, to evaluate the performance and operation of the proposed system. The results indicate that 38.84% of emissions can be avoided compared to the situation without carbon capture through the lifecycle. The natural gas cost and heat sale profit constitute the majority of annual expense and revenue, respectively. The interaction level with power grid is 6.87% at the optimal operation. Furthermore, two economic improvement measures were counted, and three disposals of the captured carbon dioxide were compared. This work may help move distributed energy systems develop towards clean, economic, and independent prosumers.