International Journal of Energy Research最新文献

Based on the first-principles calculation and grand canonical Monte Carlo (GCMC) simulation, the reversible hydrogen storage of Na-decorated silicon boron (SiB) and C-doped SiB monolayers have been investigated. For double side 4Na-decorated SiB monolayer, each Na atom can adsorb five H₂ molecules with the average adsorption energy of −0.18 eV/H₂, yielding an H₂ gravimetric density of 9.09 wt% and desorption temperature T_D of 227 K. To further improve the H₂ gravimetric density and desorption temperature, doping effect was employed to enhance the internal electric field between Na atom and SiB substrate. When two Si atoms in the SiB monolayer were replaced by C atoms, the adsorption energy for H₂ was significantly improved. The H₂ gravimetric density reaches to 10.63 wt% with the average adsorption energy of −0.22 eV/H₂. Meanwhile, the desorption temperature T_D was raised from 227 to 282 K, reaching the ideal condition near room temperature. In addition, the GCMC simulations further confirm that the H₂ gravimetric density can fully meet the latest hydrogen storage target (5.5 wt%) for both Na-decorated SiB monolayer and Na-decorated C-doped SiB monolayer. Our results indicate that both Na-modified SiB and C-doped SiB monolayers can be used as promising materials for reversible hydrogen storage.

Energy consumption has risen much more while the economy has expanded so quickly. As a result, significant environmental contamination is created, which causes public worry. Under this background, enhancing energy efficiency and lowering pollution is particularly crucial for the fulfillment of sustainable economic development. Efficiency evaluation for energy and environment is an effective measure to achieve both energy saving and emission reduction as well as sustainable social development. In this paper, energy and environmental efficiency consists of energy utilization efficiency and pollution treatment efficiency. An improved two-stage DEA model is proposed, which takes into account how stochastic and environmental factors affect decision-making units (DMUs). Finally, the author analyses the panel data of 15 cities in Southwest China from 2010 to 2018, which proves the feasibility and effectiveness of this study. The results show Southwest China’s poor energy and environmental efficiency as well as the stark differences among its cities. The scientific value revealed by this paper is as follows: (1) for the study of energy and environmental efficiency, this paper is more targeted at the differences between cities and (2) using an improved two-stage DEA model to consider the effects of stochastic factors on DMUs.

This paper presents a measurement method that utilizes object recognition technology for continuous and quantitative real-time monitoring of water levels in industrial boilers. Real-time videos of water levels were monitored using a small camera, and the YOLO algorithm, a single-stage detector, was employed to use the bounding boxes of detected objects within the video as variables, directly measuring the length ratio for each frame. The method demonstrated a high level of accuracy in water-level measurement, with an average of 99.02%, and a stable performance, with a fluctuation of 0.13% in continuous measurements. Consequently, the proposed measurement method proves feasible for quantifying continuous water levels in industrial inspection systems even in low-resource environments. These results demonstrate a new mechanism for monitoring technology, without requiring text detection, showing the potential for improving efficiency in complex boiler systems and the feasibility of reliable water-level measurement and control.

In Chile, the solar thermal regulation DS331, which utilizes a global modeling approach, governs the deployment of solar thermal systems (STSs) across highly variable climatic zones. This regulation’s one-size-fits-all approach often misrepresents the solar potential and economic feasibility in different regions. To address these limitations, we introduce a refined modular energy model that incorporates a 1D multinode stratification technique for hot water storage. This model is associated with a multiobjective optimization process using the NSGA-II algorithm, focusing on optimizing the solar collector area and storage volume to maximize solar fraction and life cycle savings (LCSs) across 20 major Chilean cities. Our results demonstrated that the optimized systems achieve solar fractions ranging from 0.92 to 1.00, significantly improving upon the current regulation’s performance, particularly in southern regions where solar radiation is lower. Notably, the optimized configurations suggested a potential reduction in collector areas by up to 20% and storage volumes by up to 15% compared to those recommended by DS331, while still exceeding the legal requirements for the solar fraction. This optimization made it possible to increase LCS by ~25%–30% across various scenarios, indicating a substantial improvement in cost-effectiveness. Based on these findings, existing solar thermal regulations should be revised to take into account local climatic and consumption data. Such adjustments would ensure more accurate sizing of STS, enhanced economic viability, and greater incentive alignment for widespread adoption. This study underlines the critical role of detailed, location-specific energy modeling in shaping effective energy policies and advancing the deployment of renewable technologies in diverse environmental contexts.

In this research, we have successfully synthesized a Ni─Fe─P/h-BN catalyst through a simple one-step electrodeposition method for efficient water splitting in a KOH electrolytic cell. Our prepared Ni─Fe─P/h-BN catalyst showcased exceptional electrocatalytic activity for the oxygen evolution reaction (OER), with an overpotential of only 210 mV at a current density of 10 mA cm⁻². Notably, this value is significantly lower compared to 248 mV observed for Ni─Fe─P/Fe without h-BN and also superior to the results reported for other catalysts. Furthermore, through the ball milling, we further enhanced the OER performance of the catalyst, achieving an impressive overpotential of 200 mV at the same density of 10 mA cm⁻². The exceptional OER performance displayed by the Ni─Fe─P/h-BN composite is attributable to the synergistic effects of Ni─Fe─P and h-BN. Furthermore, the introduction of a heterojunction between h-BN and Ni─Fe─P serves to further enhance the OER capability of the catalyst. This investigation introduces a straightforward and effective approach for fabricating cost-effective and high-performance electrocatalysts intended for water electrolysis.

In the context of the European Energy Directives for the period 2020–2035 and the perspectives for 2050, the next generations of energy systems and associated technologies for the power supply of buildings will have a significant impact on pollution and greenhouse gas emissions mitigation, generating clean electricity with financial efforts in decrease. Until recently, the processes of burning conventional fossil fuels represented the main source of thermal energy, but along with technological development, new solutions have been implemented for providing thermal energy that works based on renewable energies, and the hypothesis of heating electrification based on alternative resources is feasible. The present research article addresses the topic of Electrification of the Thermal Load by Replacing Conventional Energy with Solar Energy within a case study with practical applicability to an existing industrial production hall. This study aims to assess, within a comparative analysis, the feasibility of replacing conventional energy fossil resources with solar energy resources, with the objective of decarbonization through electrification of the heating in industrial hall workspaces. In the case study, by implementing the solar generator that has the role of taking over the building thermal load, carbon dioxide emissions are reduced by 90% compared to the heat generation using conventional fossil energy, and the costs can be reduced by around of 70% compared to the current costs charged by economic operators in the domain.

It has been recognized that fluid imbibes into the matrix and floods the oil during hydraulic fracturing; however, the mechanism of fluid imbibing into the matrix and flooding the oil remains unclear. Additionally, there is a scarcity of methods for calculating the maximum imbibition length. In this paper, we first analyzed the imbibition mechanism during hydraulic fracturing and then developed a method for calculating the imbibition length using mercury intrusion experiments, seepage theory, and numerical calculations. By comparing the proposed method calculations with experimental results and published model calculations, we verified our proposed method. Finally, we presented the influences of the maximum imbibition length. From the work, we can know that imbibition during hydraulic fracturing involves counter-current imbibition under surrounding pressure. The influence of permeability on threshold pressure gradients was found to be greater than that on capillary pressure, resulting in an increase in the maximum imbibition length with increased permeability (ranging from 0.01 to 0.2 × 10⁻³ μm²), while the time taken to achieve the maximum imbibition length decreased exponentially. When the reservoir permeability was 0.1 × 10⁻³ μm², the contact angle was 60°, and the interface tension was 50 mN/m, the maximum imbibition length was 1.8 m, and the time of achieving maximum imbibition length was 70 days. This study provided a method for evaluating the extent of imbibition.

The release of methane into the working area of coal mines can affect safety and production. Therefore, methane drainage reduces the risk of explosion and can be used as a fuel and energy source. One methane drainage method is cross-measure borehole drilling, which involves drilling boreholes from tailgate roadways to the roof or floor layers of a mined seam. In this method, determining the appropriate distance between methane drainage stations has a significant impact on increasing the efficiency of operation and reducing drilling costs and the time required for drainage operations from each station. In this paper, a new 3D numerical model is developed for methane drainage from an underground coal mine to determine the suitable distance between methane drainage stations in the cross-measure borehole method using COMSOL Multiphysics software. For this purpose, by considering the porous media flow module and the laws related to the movement of gas in the goaf, different numerical models for distances of 10, 15, 20, 25, and 30 m were simulated. The simulation results showed that by reducing the distance between methane drainage stations, the speed of gas flow in the borehole and the amount of gas removed from the boreholes in a similar period of time increase to an acceptable level. In addition, the implementation of this model in a case study showed that a distance of 10 m between drainage stations increases the efficiency of boreholes to approximately 20%. Numerical simulation in this study can provide basic support for the design of drainage boreholes and reduce the risk of gas in underground coal mines.

In the present study, we aimed to destabilize the Ti–Al system with nonmetallic oxygen. The synthesis of α-(Ti, Al)[O] starting from TiO₂, Ti, and Al was carried out through the arc melting method, resulting in three different oxygen content levels, 3.4, 10, and 20 at%. The room temperature activation of α-(Ti, Al)[O] was not successful, and the activation was performed at 300°C under 5 MPa H₂ pressure. The structural changes after hydrogenation (maximum absorption capacity of 3.74 wt% hydrogen) arose from the transformation of α-(Ti, Al)[O] to cubic (Ti, Al)[O]H_x (c-(Ti, Al)[O]H_x); nonetheless, they recovered their original lattice parameters, which are meaningfully larger than those of α-Ti, after dehydrogenation. The hydrogen storage capacities for various α-(Ti, Al)[O] compositions generally decreased with increasing oxygen (3.4 and 10 at%) and aluminum content in the alloy. In contrast, for the compositions with a higher oxygen content of 20 at%, the hydrogen storage capacity slightly increased as the Al concentration increased: Ti_0.790Al_0.010O_0.200 absorbed 2.91 wt% hydrogen, whereas Ti_0.767Al_0.033O_0.200 absorbed 3.04 wt% hydrogen. The thermogravimetric analysis showed that samples with 20 at% O released hydrogen at lower temperatures even though the major phase after hydrogenation is c-(Ti, Al)[O]H_x regardless of the oxygen content.