Energy technology最新文献

The implementation of the jet impingement technique in air-cooled building-integrated photovoltaic-thermal (BIPV/T) systems is a promising yet underexplored solution. To assess its potential, a multivariant numerical study of various geometries was carried out. The parameters were derived from an innovative integration of the BIPV/T system with an air-source heat pump. Steady-state computational fluid dynamics (CFD) simulations employed the discrete ordinate radiation and shear stress transport k–ω turbulence models. Systems with different nozzle heights and perforated jet plate positions were compared to a straight-channel reference. Both nozzle-based and perforated jet plate configurations outperformed the reference, increasing thermal efficiency by 15.9%–32.1% and 3.5%–4.1%, electrical efficiency by 13.1%–22.7% and 5.0%–5.6%, and net power output by 10.9%–23.6% and 8.4%–20.4%, respectively. Placing nozzle outlets closer to the PV roof tile rear wall improved collector performance with only minor pressure drop changes (≤19.55%). The perforated jet plate performed best when positioned 25 mm from the rear wall, as flow resistance increased parabolically (up to 13-fold). Final recommendations were based on the newly proposed electro-thermo-hydraulic performance parameter (ETHPP), reflecting energy balance and the power-to-heat cost ratio. ETHPP distributions confirm that nozzle configurations are highly justified, with values of 1.02–1.24 across all conditions, consistently outperforming the perforated jet plate variant.

Bipolar plate is one of the most important components of proton exchange membrane fuel cells, which has the basic functions of conducting electricity, supporting membrane electrode assemblies, uniformly distributing and isolating reactant gas, circulating coolant, and rapid heat dissipation. In this article, taking the micro runner flexible forming process of 316L stainless steel sheet as the research object, the influence of process parameters on the forming quality of micro flow runners is analyzed. The results show that an increase of the equipment pressure and a decrease of the soft film hardness are conducive to the improvement of the forming depth of a bipolar plate, while the holding time has a minor effect on the forming depth. Under the same loading conditions, the forming depth of a 0.1 mm thick sheet is smaller than that of a 0.075 mm sheet. An increase of the grain size reduces the difficulty of forming, and the larger the grain size, the larger the forming height and runner filling rate. However, with an increase of the grain size, the surface roughness of the bipolar plate increases and the wall thickness of some parts of the runner becomes uneven.

The microporous layer (MPL) plays a crucial role in regulating the water transport process within the gas diffusion layer (GDL) of proton exchange membrane fuel cell (PEMFC). A two-dimensional GDL model is established, and key parameters such as wettability, intrusion thickness, and porosity of the MPL are systematically analyzed based on the volume of fluid (VOF) method. This study aims to explore its effects on the distribution characteristics of liquid water, breakthrough behavior, and liquid water saturation within the GDL. The results reveal that the nonuniform wettability MPL limited the lateral diffusion of liquid water within the GDL, allowing liquid water to flow along the established path. The liquid water saturation within the GDL is reduced by 12% compared to the uniform wettability. The greater the MPL thickness, the fewer the liquid water breakthrough sites at the interface between the MPL and the macroporous substrate (MPS). There are 15 liquid water breakthrough sites at the interface at a thickness of 5 μm, and at a thickness of 45 μm, the number of breakthrough sites is sharply reduced to 2, and the time for liquid water to break through the interface is reduced by 44.8%.

Plastic waste management and the fabrication of low-cost, high-performance energy storage and glucose-sensing devices are the need of the hour. This work focuses on the deposition of nickel–phosphorus (Ni–P) thin films via an ecofriendly and cost-effective electroless deposition method on waste plastic substrates obtained from used beverage cups. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) are used to investigate the surface morphology and roughness of the deposited film, respectively, revealing uniform deposition and a root-mean-square (RMS) roughness of 67.17 ± 14.5 nm. X-ray diffraction (XRD) analysis confirmed the amorphous nature of the film. Electrochemical studies demonstrated outstanding glucose-sensing performance of the fabricated flexible electrode with a high glucose sensitivity of 1.43 mA/cm²·mM and a low limit of detection of 74.86 µM within a linear range of 0.2–2 mM, along with excellent selectivity in the presence of common interfering species. Additionally, the electrode showed impressive energy storage performance for supercapacitor applications, achieving a maximum specific capacitance of 571.43 F/g at a current density of 1 mA/cm² with exceptional stability. These findings highlight a sustainable and scalable route for transforming waste plastics into high-value functional materials for next-generation flexible electronics.

The solid polymer electrolytes (SPEs) based on a mixture of iodine (I₂), potassium iodide (KI), polyvinyl alcohol (PVA), and polymer F-127 were investigated. The compositions 0.54 PVA, 0.060 F-127, 0.40 KI, and 0.04 I₂ had the maximum room temperature conductivity (8.2891 × 10⁻⁴ mS cm⁻¹) (for 0.5 g total weight). The electrolyte's ideal mobile ion density is responsible for this increased conductivity. The Vogel–Tamman–Fulcher (VTF) relationship governs the change in conductivity with temperature. These PVA-based SPEs were employed as electrolytes in perovskite-sensitized solar cells, including 10–60 weight percent KI and I₂. The short-circuit current density (J_sc) improved with increasing KI content, boosting power conversion efficiency (η), which peaked at 40 weight percent KI at 4.74%. Characterization of I–V parameters, scanning electron micrographs (SEMs), and X-ray diffraction (XRD) analysis, along with the measurement of the photostability of the prepared solar cells constitutes part of the investigation. These findings determine the performance of PVA-based SPEs in the field of energy conversion and perovskite solar cells.

Triboelectrification-induced electroluminescence (TIEL), as an emerging light-emitting mechanism, integrates self-powering capability and low-stress activation capability. By comparison, while traditional mechanoluminescence (ML) requires a pressure threshold at the MPa level for activation, electroluminescence (EL) relies on complex external circuits. TIEL thus demonstrates significant potential in the fields of wearable devices and intelligent sensing. In this study, ZnS:Cu/PVDF/PDMS stretchable photonic composite films were engineered based on TIEL principles. Integrated with a single-electrode triboelectric nanogenerator (TENG), the system achieves optical–electrical dual-responsive characteristics with exceptional performance (1.56 μW cm⁻² optical power density, 30.1 nC charge output), durability (>3000 cycles), and stress sensitivity (0.65 V kPa⁻¹), the TIEL peak dynamic curve is distinguished from the noise region by an interval of 95 ms, and the response time is only 2 ms, enabling precise detection of weak mechanical stimuli and rapid dynamic changes. For practical validation, this photonic skin enables gesture recognition through synchronized optical–electrical signal mapping and high-security handwriting authentication through dual-modal cross-verification. The high-performance stretchable optical–electrical dual-responsive photonic skin developed in this study not only retains the intuitiveness of optical detection but also incorporates the reliability of electrical sensing, providing an innovative solution that combines high precision with enhanced security for intelligent interaction.

This paper uses numerical simulations to study the effects of six twisted-strip inserts (multipassage, perforated (PF), center-cleared (CC), single-passage), their twist direction and pitch on the heat transfer, and flow resistance of twisted elliptical tubes. Multipassage strips (5-passage most effective) boost heat transfer-Nusselt number up 1.19–1.7 times versus tubes without inserts-but sharply increase flow resistance (friction factor up 3.01–3.29 times). PF and CC strips balance heat transfer improvement with controlled resistance growth, with the latter showing optimal comprehensive performance in high-Reynolds-number regions (excellent overall performance factor values). Counter-inserted strips outperform normally-inserted ones in heat transfer but raise resistance more, with higher Nusselt numbers and friction factors at the same Reynolds number; counter-inserted CC strips perform best (Nusselt number up 1.14–1.23 times, friction factor up 2.49–2.86 times). For single-passage and CC strips, smaller twist pitch enhances Nusselt number and friction factor more regardless of insertion direction, and the normally-inserted CC strip with 150 mm pitch achieves the best comprehensive performance factor.

This study addresses the tracking of the maximal electrical power generated in series-connected hybrid photovoltaic-thermoelectric (PV-TE) energy harvesting systems in low-power applications. The integration of PV-TE technologies in a hybrid energy harvesting system enhances electricity generation from sunlight by combining the properties of PV cells with the thermoelectric effect in thermoelectric generators. However, the inherent differences in electrical characteristics between the photovoltaic cell and the thermoelectric generator pose challenges in achieving the maximum power point (MPP) for the overall hybrid system. This work reviews the potential of the “differential power processing” (DPP) approach, as well as the associated architectures, DC–DC converter topologies, and maximum power point tracking (MPPT) algorithms. The final goal of this study is to identify the most suitable solutions for low-power hybrid PV-TE systems connected in series, implementing the DPP approach.

The long-term performance and efficiency of n-type TOPCon (tunnel oxide passivated contact) solar cells are often compromised by degradation mechanisms, particularly edge recombination and environmental factors. While various passivation strategies exist, their practical application can be limited. This work introduces and systematically evaluates a scalable, low-temperature Nafionedge passivation method, uniquely demonstrating its superiority not only to untreated cells but also to conventional nitrogen treatment and a sequential nitrogen-Nafion combination. The study compared untreated cells to those treated with nitrogen, Nafion, and both, revealing that the standalone Nafion treatment is the most effective approach for performance enhancement and degradation mitigation. Critically, Nafion-treated cells achieved the highest performance, with a fill factor (FF) of 78.61% and efficiency of 21.84%. These cells also exhibited exceptional long-term stability, showing only a 6.77% reduction in performance, significantly outperforming untreated cells (12.46% reduction) and, notably, the cells treated with the combined nitrogen-Nafion process (10.66% reduction). This finding suggests that a single-step Nafion application is more effective than a multistep process involving high-temperature annealing. PVsyst simulations further validated these improvements in stability and efficiency, underscoring Nafion edge passivation as a powerful and practical strategy for optimizing the design and maintenance of durable photovoltaic systems.

In this work, nanocomposites of graphenated carbon nanotubes (g-CNTs) conformally coated with TiO₂ by atomic layer deposition (ALD) were produced. g-CNT forests were grown on silicon substrates by microwave plasma–enhanced chemical vapor deposition (915 MHz), and the density of graphene foliates was tuned by adjusting the growth time at 1050°C. TiO₂ thickness was controlled via the number of ALD cycles. The resulting electrodes comprise aligned, high-aspect-ratio nanotube arrays whose average diameter varies with the foliate thickness and the TiO₂ cycle number. Electrochemical impedance spectroscopy and cyclic voltammetry show that the TiO₂ coating improves cyclic stability and increases specific capacitance relative to pristine g-CNTs. This enhancement arises from the synergy between the high conductivity and electric double-layer capacitance of g-CNTs and the Faradaic pseudocapacitance of TiO₂. Finally, we identify a trade-off between foliate density and TiO₂ thickness that defines a tunable parameter space for optimizing g-CNT/TiO₂ electrodes.