Search Results (822)

To quantitatively evaluate the environmental performance of a Chinese solar greenhouse (CSG) in Northern China during the autumn–winter season and explore its matching relationship with the growth requirements of autumn–winter tomato production, continuous monitoring data collected throughout the tomato growing season were analyzed. The growth period was divided into four stages: Seedling, Flowering, Swelling, and Fruiting. An indicator framework was established to analyze air temperature, solar radiation, and humidity inside the CSG. Results showed that total indoor growing degree days (GDD) reached 1326.77 °C·d by harvest, substantially higher than outdoor conditions (476.30 °C·d). Stage-wise GDD exhibited a bimodal pattern, with the Seedling and Fruiting stages contributing 37% each, whereas the Swelling stage contributed only 10.38%. Notably, the relative GDD index (RGI) revealed a stage-specific thermal mismatch, peaking at 1.64 during the Seedling stage (indicating thermal surplus) and dropping to 0.67 during the Fruiting stage (reflecting heat insufficiency in deep winter). Across all growth stages, indoor daily mean accumulated radiation ranged from 7.05 to 8.12 MJ·m⁻²·d⁻¹, and transmittance increased from 61% to 85%. Nevertheless, indoor radiation supply remained strongly constrained by the seasonal decline in outdoor radiation. Humidity regulation displayed pronounced diurnal asymmetry and stage-specific differences. Relative humidity (RH) suitability rates across the four growth stages were 57%, 16%, 12%, and 17%, respectively. Low humidity was prominent during the Seedling stage, with RH below 60% accounting for 32% of the time. High humidity dominated the Swelling and Fruiting stages, with RH above 80% accounting for 67% and 72% of the time, respectively, accompanied by frequent short-term low-humidity fluctuations. Overall, although CSGs in Northern China can effectively buffer external low temperatures during autumn–winter production, they still face challenges such as stage-specific imbalances in solar thermal energy storage and release, weak indoor light availability (especially during winter), and insufficient synergistic humidity regulation. Full article

Hybrid solar–thermal energy harvesting systems are an important advancement in renewable energy technology, enabling simultaneous production of electrical power and useful thermal energy within a single compact platform. However, their performance is often limited by poor heat transfer and inefficient mass transport of working fluids, leading to photovoltaic thermal degradation and significant exergy losses. This study aims to optimize heat and mass transport processes in a hybrid solar–thermal mechanical system to enhance energy recovery and ensure long-term operational reliability. A three-dimensional numerical model based on the finite volume method (FVM) was developed using the governing equations of continuity, momentum, and energy conservation. A Multi-Objective Genetic Algorithm (MOGA) was employed to determine optimal microchannel geometries by analyzing variable cross-section effects on flow behavior and thermal boundary layer disruption. At the Reynolds number of 2000, the optimized configuration increases the average Nusselt number by 43.5% compared to a smooth channel. Consequently, the photovoltaic operating temperature decreases by 12.6 °C, improving electrical efficiency by 9.3%. The system achieves a maximum thermal efficiency and net energy gain of 76.8%, while maintaining an acceptable 16.3% increase in pumping power. The results confirm that optimizing mass transport is essential for effective thermal regulation and improved energy conversion performance, providing a strong foundation for high-efficiency solar collector design. Full article

Türkiye’s strategic geographical location offers an exceptional opportunity for solar energy harvesting, yet optimizing large-scale investments requires rigorous pre-assessment methodologies. This study presents a comprehensive multi-criteria techno-economic analysis and real-world validation of a 13.18 MWp solar power plant (SPP) located in Kirsehir, a region characterized by high solar irradiance (1750 kWh/m²). Utilizing PVsyst software, four distinct configurations—monofacial and bifacial modules at 21° and 25° tilt angles—were systematically simulated and evaluated across varying equity-to-loan ratios using key financial indicators (NPV, IRR, PI, and Payback Period). The simulation results identified the 21° bifacial configuration, enhanced by the innovative integration of high-albedo industrial calcite (CaCO₃) waste as ground cover, as the optimal engineering solution. Crucially, the accuracy of this optimization was evaluated against 12 months of field data. While the raw measured annual production was recorded as 22,793,323 kWh, the validation was strictly based on the production adjusted for grid outages (23,499,604 kWh). Comparing this adjusted value with the simulated annual generation (22,816,114 kWh) yielded a total annual discrepancy of only 3% and a volumetrically weighted average error of 5.07%. Furthermore, to isolate model fidelity from inter-annual meteorological variability, the validation was assessed using the Performance Ratio (PR). The adjusted volumetrically weighted PR (87.43%) demonstrated a remarkably close alignment with the simulated PR (87.48%), exhibiting a marginal deviation of merely 0.05%. These performance metrics indicate a general consistency between the simulation model and operational field records across the evaluated period. Environmentally, the maximized energy yield of the 21° bifacial system facilitates the avoidance of approximately 6507.58 tonnes of CO₂ emissions annually. This research not only establishes the viability of scalable, low-cost calcite ground covers but also provides a highly robust, de-risked decision-support framework for utility-scale PV investments in similar geographic latitudes. Full article

The development of indoor photovoltaic devices for powering Internet of Things (IoT) sensors requires low-cost and sustainable components, making dye-sensitized solar cells (DSSCs) an ideal candidate for artificial light harvesting. The counter electrode plays a critical role in transferring electrons and catalyzing the reduction in the redox electrolyte. However, the traditional use of expensive and scarce platinum (Pt) limits the cost-effective, large-scale commercialization of these devices. While carbon-based materials offer a highly porous, conductive, and abundant alternative, commercial carbon pastes frequently require energy-intensive high-temperature sintering. In this study, we propose a sustainable, low-temperature, and screen-printable carbon composite counter electrode (LoT-HPC) using bio-derived hydroxypropyl cellulose (HPC) as a highly effective binder. Rheological characterizations confirm that the formulated LoT-HPC ink possesses an ideal shear-thinning profile and rapid structural recovery, ensuring excellent printability and film homogeneity. By comparing the custom LoT-HPC composite against a commercial high-temperature screen-printed graphite paste (HT-Elco) and a standard sputtered Pt-FTO electrode, we demonstrate the structural and electrocatalytic advantages of this material. When integrated into full DSSC devices and evaluated under low indoor illumination (1000 lux), the LoT-HPC cell delivers a power conversion efficiency (PCE) of 14.8% and a high short-circuit current density of 103.9 µA cm⁻². Furthermore, the custom device demonstrated exceptional operational stability, retaining 98.6% of its initial efficiency (from 14.8% to 14.6%) after 200 h of continuous light-soaking and J-V cycling under 1000 lux. Ultimately, the successful implementation of the HPC binder enables the low-temperature fabrication of sustainable carbon counter electrodes without the need for energy-intensive thermal treatments, presenting a highly scalable pathway for indoor DSSC manufacturing. Full article

Omnidirectional optical devices are essential for photodetection, thermal radiation regulation, and solar energy harvesting. However, the photonic bandgaps and defect modes of conventional one-dimensional photonic crystals (1DPCs) are constrained by the Bragg scattering condition, leading to strong angular dependence that substantially limits their practical applications over wide angle ranges. In this work, we theoretically design and experimentally verify an angle-insensitive photonic crystal defect-mode absorber based on hyperbolic metamaterials (HMMs). Leveraging the unique isofrequency dispersion of HMMs, we introduce a phase compensation mechanism into a photonic crystal composed of alternating HMM and dielectric layers. Calculations show that inserting a metallic defect layer excites a highly localized defect mode within the bandgap, whose resonant wavelength remains almost unchanged with incident angle. To simplify fabrication and enhance absorption, we reduce the number of periods and design a heterostructure containing subwavelength Ag/TiO₂ multilayers. Measurements under TM polarization over 0–70° show that the defect-mode peak shifts by only 3.5 nm, while the absorptance decreases from ~0.717 at normal incidence to ~0.292 at 70°. This study provides an effective strategy for designing and fabricating resonance wavelength angle-insensitive optical absorbers enabled by HMM-based phase compensation. Full article

This review systematically summarizes recent advances in moisture-electric generation technology from four perspectives: functional-material modification, device-structure design, multi-source energy-harvesting strategies, and practical applications. It discusses the classification and modification of moisture-responsive functional materials; analyzes how device architectures regulate ion transport, reviews the mechanisms of coupling moisture energy with solar, thermal, and mechanical energy; and summarizes representative applications of moisture-electric generators (MEGs) in power supply, self-powered sensing, and wearable electronics. The review further compares the advantages and limitations of different material and structural strategies and evaluates challenges related to output performance, environmental adaptability, long-term stability, power management, and scalable fabrication. Finally, future research directions are discussed to support the practical development of MEGs. Full article

Group III-nitride semiconductors (GaN, AlN, InN) serve as foundational materials for modern optoelectronics, high-frequency microelectronics, and next-generation energy harvesting devices. However, traditional high-temperature epitaxy (>700 °C) introduces severe thermal stress, high dislocation densities, and fundamental incompatibility with flexible substrates or CMOS back-end-of-line (BEOL) processes. Plasma-enhanced atomic layer deposition (PEALD) provides a disruptive, ultra-low thermal budget (<300 °C) pathway for atomic-scale precision growth and conformal coating. This review systematically summarizes recent frontiers in PEALD-synthesized Group III-nitrides and 2D/3D polar heterostructures. First, we dissect the microscopic nucleation kinetics, surface bond reconstruction, and impurity suppression mechanisms across diverse substrates, including Si, sapphire, quartz, metals, and flexible polymers. Next, we highlight 2D template-assisted van der Waals epitaxy on graphene and MoS2, and elucidate polarization-driven dipole interactions and band alignment engineering at 2D/3D polar interfaces (e.g., α-In₂Se₃, Janus MoSSe). Furthermore, we comprehensively discuss innovative applications in advanced photovoltaics (as electron transport and passivation layers in perovskite and quantum dot-sensitized solar cells), silicon-based microcavity lasers, high-electron-mobility transistors (HEMTs), and flexible multimodal sensors. Finally, key technological challenges—including the low-thermal-budget paradox, wafer-scale uniformity, and deposition throughput—are addressed alongside future perspectives in area-selective ALD and neuromorphic computing, presenting a cohesive blueprint from underlying physics to macroscopic system integration. Full article

Precision agriculture and sustainable farming practices require autonomous environmental monitoring systems capable of operating in remote areas with limited energy and connectivity. However, the high cost of existing professional technology remains a significant barrier to widespread adoption. This study presents the development of a solar-powered smart sensing node designed for autonomous operation that integrates TinyML and dual-mode wireless connectivity via LoRaWAN and Wi-Fi for intelligent monitoring. The system features a custom-designed cup anemometer and multispectral sensing capabilities integrated into a compact single-tower architecture. All structural components, including radiation shields and a modular PVC frame, were designed for low-cost manufacturing and mass production. A single hermetic housing protects the core control electronics and is designed to improve durability in harsh outdoor environments. A Multi-Layer Perceptron model was implemented on the edge to enable intelligent data fusion and compensation, while a dynamic sampling strategy optimized power consumption. Experimental results demonstrate the feasibility of the proposed architecture through adaptive spectral acquisition over a daily illumination cycle, embedded MLP-based sensor fusion, and telemetry-oriented data compression that substantially reduces the number of transmitted samples. The main contribution of this work is a system-level architecture that integrates sensing, embedded intelligence, solar-energy harvesting, hybrid wireless communication, and telemetry optimization into a compact, low-cost, and field-deployable prototype IoT platform for sustainable precision agriculture. Full article

Measuring the water table level is a critical factor in irrigated agriculture in arid regions, as it can significantly influence the exchange of water and nutrients with crops. This work presents the design, implementation, and field validation of an open-source, solar-powered IoT device for autonomous groundwater level monitoring, combining long-range low-power LoRa communication, a non-contact pressure-based level sensor using the trapped-air capillary method, and an efficient power management stage that seamlessly switches between solar and battery power. Unlike existing commercial leveloggers, which are costly and lack integrated wireless telemetry and solar-based autonomy, the proposed platform is presented as a fully open-source, low-cost alternative purpose-built for unattended deployment in areas without grid power or cellular coverage. The system was validated through a multi-day field trial and dedicated communication tests, demonstrating a stable power conversion efficiency of 84–90%, a five-day autonomous operation without any deep-discharge event, high linearity ($R^2$ = 0.9998) of the level module over a 0–2 m range with a resolution of approximately 1.94 mm per ADC count, and a reliable LoRa link of up to 8.51 km in an urban/suburban environment despite non-line-of-sight conditions. With an estimated hardware cost of approximately $100 USD per unit, the device represents a low-cost, low-maintenance tool capable of generating knowledge about water resources to optimize irrigation and crop management in the face of climate change. Full article

Developing efficient, stable, and low-cost photocatalysts is the key to achieving large-scale photocatalytic hydrogen production. Herein, a universal fluoride-induced sulfur vacancy engineering strategy is proposed for the full Mn_xCd_1−xS solid solution series (x = 0.1–0.9), with Mn_0.6Cd_0.4S selected as the representative optimal sample. By introducing ammonium fluoride during the hydrothermal process, controllable sulfur vacancies are generated to enable efficient separation and transfer of photogenerated charge carriers for high-efficiency hydrogen production. Impressively, the optimal fluoride-modified Mn_0.6Cd_0.4S (F-MCS) photocatalyst shows the fastest hydrogen production rate up to 8.08 mmol·g⁻¹·h⁻¹, which is 1.5 times that of pure MCS nanoparticles, as well as enhanced photochemical stability. Quantitative EDS elemental analysis verifies that 1.2 at.% fluorine is incorporated into the lattice of F-MCS, rather than being physically adsorbed as residual ammonium fluoride precursors. Experimental results reveal that the introduction of NH₄F can effectively facilitate the sulfur vacancy formation in MCS, which alters the band position of MCS nanoflakes for increased light harvesting, and serves carrier separation centers for promoting the efficient transfer of photogenerated charge carriers. This study provides valuable insights into the design of a solid solution-based photocatalyst for efficient solar-driven hydrogen production for sustainable energy applications. Full article

The building envelope is a key lever for reducing energy demand and carbon emissions in the built environment. However, conventional envelope systems remain largely static and are unable to respond effectively to changing climatic conditions. Biomimetics has emerged as a promising approach for the development of climate-adaptive envelope solutions. Nevertheless, research in this field remains fragmented across disciplines, and its evolution and technological maturity have not yet been systematically assessed. This study proposes an integrated analytical framework combining a bibliometric analysis of 2.007 Scopus-indexed documents, based on a VOSviewer keyword co-occurrence network, with a cluster-guided state of the art review, and a Technology Readiness Level (TRL) assessment of selected biomimetic envelope solutions. The TRL assessment is conducted using explicit operational criteria. The analysis identifies three main research clusters: (C1) environmental-performative, focusing on energy efficiency and envelope optimisation; (C2) material-experimental, addressing biomimetic composites and innovative materials; and (C3) technological fabrication, centred on digital fabrication, smart materials, and 4D printing. Temporal trends reveal a shift after 2018 from materials science-oriented studies towards computational design and adaptive manufacturing, providing quantitative evidence of a transition previously described mainly in qualitative terms. The review highlights a strong focus on solar-shading applications, while energy harvesting and passive thermoregulation remain comparatively underexplored. The TRL assessment shows that more than 80% of the analysed solutions are concentrated at TRL 3, indicating an early stage of technological development. The main barriers include limited material durability, non-standardised production costs, and regulatory constraints. The findings suggest that future progress will depend less on the identification of new biological inspirations and more on advancing the technological maturity and industrial scalability of existing concepts. This will require integrated developments in materials, parametric design, life-cycle assessment, and regulatory frameworks. Full article

The practical performance of building-integrated solar systems in cold climates is strongly governed by temperature-grade matching between solar energy output and space-heating demand. However, year-round field evidence comparing solar thermal collectors, photovoltaic systems, and photovoltaic/thermal systems under the same building, climatic, and heating-network boundary conditions remains limited. This study conducted a year-round field evaluation of solar collector (SC), photovoltaic (PV), and photovoltaic/thermal (PVT) systems installed in an office building in Tianjin, China. Continuous operating data collected from November 2022 to October 2023 were used to assess seasonal thermal output, electricity generation, effective heat supply, solar utilization efficiency, carbon reduction, and payback period. During the heating season, SC exhibited the strongest direct-heating capability among the investigated systems, delivering 817.50 MJ/m² of useful heat. In contrast, under the investigated system configuration without heat-pump assistance, the outlet temperature of the PVT subsystem remained below the 45 °C direct-heating threshold, and its thermal output could not be directly utilized for winter space heating. This result is specific to the investigated operating conditions and does not exclude the potential application of PVT systems coupled with heat pumps or low-temperature heating terminals. During the non-heating season, the investigated PVT subsystem simultaneously produced electricity and usable low-temperature heat, with heat and electricity accounting for 61.3% and 38.7% of its useful output, respectively, indicating its potential for combined energy harvesting. Under the investigated climatic, system, cost, and energy-demand conditions, the entropy-weighted TOPSIS assessment ranked SC highest when non-heating-season heat demand was present, whereas PV was more suitable when such heat demand was absent. Furthermore, a demand–output matching method was developed to support SC/PV area allocation for different building types. Under the investigated climatic and energy-demand assumptions, the recommended PV area ratios were 54.5%, 67.4%, and 79.7% for residential, office, and commercial buildings, respectively. These results provide field evidence for effective heat evaluation, temperature-grade matching, and component selection in solar-assisted heating systems for cold-climate buildings. Full article

Global requirement of clean, cost-effective and sustainable energy has stimulated massive research and development in photocatalytic materials that have the potential to harvest solar based energy while mitigating the environmental issues. Among various materials, perovskite oxides have emerged as a promising energy resource. Owing to the structural versatility, optical and electrical properties, chemical inertness allows the use of material of multifunctional prospects. Currently Strontium titanate (SrTiO₃), a vital perovskite oxide having a band gap nearly ~3.2 eV, is showing significant function for photocatalytic water splitting, carbon dioxide conversion and degradation of organic pollutants. Though within the UV spectrum, its intrinsic photocatalytic behavior is limited to approaches such as graphene junctions, noble-metal support, and post-synthetic heat treatment seem to promote the adsorption within visible-light. Strontium titanate also demonstrates photo charge separation efficiency, and long-term catalytic durability. Moreover, modifications and hydrothermal synthesis have proven extremely efficient for nano-based engineering, control over crystal diameter, defects, and shape, which can result in magnificent composites that can be promising substitutes. Therefore, further research is imperative regarding these material application prospects. This comprehensive review provides insights into details on the potential of nanoengineering and composite approaches to reduce the inherent limitations of perovskite oxides, especially Strontium titanate, and enabling additional applications in next-generation photovoltaic and solar energy harvesting technologies. Full article

High-efficiency perfect absorption, spanning the entire visible region, plays an increasingly significant role in applications such as solar energy harvesting, photodetection, and thermal radiation management. However, the complexity and manufacturing difficulty of the currently proposed structures hinder large-scale application. In this work, we propose a broadband perfect absorber based on a tungsten–silicon nitride–tungsten (W-Si₃N₄-W) sandwich multilayer film. We combine the unique broadband absorption capability and high-temperature stability of material W with the low-loss characteristic of material Si₃N₄. By optimizing the geometrical parameters of the structure, we successfully achieved an average absorption efficiency exceeding 94% across a wide wavelength ranging from 500 nm to 900 nm. This work paves the way for developing high-performance, stable, and broadband absorption devices. Full article

We report the study of Cur@HKUST-1 composites, obtained through one-pot infiltration of HKUST-1 with curcumin (Cur) as a guest-sensitizing molecule. Cur features a HOMO energy above the valence band (VB) of HKUST-1, enabling modulation of the electronic structure of the host framework by introducing additional energy states within the bandgap. Structural characterization, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), confirmed successful guest incorporation and preservation of HKUST-1 crystallinity. An initial Cur amount of 50% (relative to the BTC linker) was added to the synthetic mixture, and differential UV-vis analysis has shown an infiltration efficiency of 28.0%, corresponding to an infiltration degree of 14% in the Cur@HKUST-1 composite, highlighting a challenging loading process, primarily due to the size and conformations of the Cur structure. Textural analysis revealed a reduction in surface area and pore volume, consistent with a high degree of guest infiltration. Optical properties evaluated by diffuse reflectance UV-vis spectroscopy revealed new absorption bands and a notable decrease of 1.83 eV in the bandgap energy from 3.68 eV (HKUST-1) to 1.85 eV (Cur@HKUST-1) due to guest molecule infiltration. Density functional theory (DFT) calculations supported the experimental findings, showing that guest HOMOs promoted the formation of a new valence band (VB), while the original VB remains lower in energy. Density-of-states analysis confirmed that the new VB originates from 2p orbitals belonging to the guest, while the conduction band remains predominantly Cu-based from the HKUST-1 framework. Photoelectrochemical characterization revealed that the guest-modified material exhibits an enhanced photocurrent response compared to HKUST-1. Cur@HKUST-1 displayed higher stability and stronger photocurrent density, attributed to its narrower bandgap and increased charge carrier density. These results demonstrate the potential of rational guest selection to engineer band structure and improve the light-harvesting performance of MOFs in solar-driven applications. Full article