Energy最新文献

{"title":"Numerical study on transient critical heat flux prediction with dynamic bubble simulation under exponentially escalating heat input","authors":"Xinyan Xu ,&nbsp;Shuwen Yu ,&nbsp;Changhong Peng","doi":"10.1016/j.energy.2025.135785","DOIUrl":"10.1016/j.energy.2025.135785","url":null,"abstract":"<div><div>This paper presents the development and validation of numerical transient critical heat flux (CHF) prediction model based on the coupling of dynamic bubble simulation by Monte Carlo (MC) method and two-dimensional heat conduction model of the substrate by finite volume method. The model aims to predict the transient CHF value, estimate the dynamic heat flux and temperature distribution and evaluate various phenomena of bubble behaviors during transient boiling heat transfer process under exponentially escalating heat power input. The dynamic bubble simulation is performed by modeling and tracking bubble nucleation, bubble growth, bubble departure and bubble coalescence procedures of individual bubbles in real time based on simplified fundamental bubble parameters including nucleation site density (NSD), bubble departure diameter, bubble growth and waiting time. The heat flux partitioning model was used to evaluate different heat fluxes based on the classification of microlayer and dry spot regions. According to the dynamic heat flux boundary due to dynamic bubble behavior and exponentially escalating heat input, the thermal conductivity model was coupled to feed back the wall temperature distribution for further updates and simulation of dynamic bubble behavior. Numerical simulation results showed good agreement with transient flow boiling experimental results with escalating periods ranging from 500 ms to 5 ms, and the results showed the trend that the transient CHF value increases with decreasing escalating period as observed in experiments. Sensitivity analysis of input bubble parameters was performed and showed that the model is more sensitive to bubble departure diameter and bubble waiting time.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"323 ","pages":"Article 135785"},"PeriodicalIF":9.0,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of impurity particles on non-equilibrium condensation flow characteristics in steam turbine","authors":"Pengfei Hu ,&nbsp;Mingyang Sun ,&nbsp;Yiyuan Zhao ,&nbsp;Weifei Gu ,&nbsp;Jie Wan ,&nbsp;Qi Li","doi":"10.1016/j.energy.2025.135799","DOIUrl":"10.1016/j.energy.2025.135799","url":null,"abstract":"<div><div>In a steam turbine, the rapid expansion of steam can induce non-equilibrium condensation, which is significantly influenced by the presence of impurities. The primary purpose of this investigation is to determine the optimal particle conditions to minimize wet steam losses in heterogeneous condensation flows. First, a numerical model is improved to simulate heterogeneous condensation, focusing on the nucleation process on solid particle surface. Then, the model is applied to investigate heterogeneous condensation characteristics within the Moses-Stein nozzle and Dykas cascade. Finally, the impact of heterogeneous condensation on wet steam loss is evaluated in terms of thermodynamic loss ratio (TLR) and wetness fraction ratio (WFR). Research results indicate that heterogeneous condensation significantly suppresses condensation compared to homogeneous condensation and markedly improves distribution of flow field parameters within the nozzle. However, wetness increases with higher particle concentration and particle radius. Under optimal particle conditions, the wetness at the nozzle outlet is reduced by 8 %, effectively decreasing wet steam loss due to condensation. For the Dykas blade cascade, with a particle concentration of 1 × 10¹⁶ kg⁻¹ and a particle radius of 1 × 10⁻⁹ m, thermodynamic loss is reduced by approximately 15 %, and wetness decreases by about 5 % compared to homogeneous condensation.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"323 ","pages":"Article 135799"},"PeriodicalIF":9.0,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of hybrid active-passive solar heating system through day-ahead and real-time control","authors":"Dehan Liu,&nbsp;Jing Zhao,&nbsp;Zhe Tian,&nbsp;Yawen Li,&nbsp;Zilan Yang,&nbsp;Shilei Lu,&nbsp;Quanyi Lin","doi":"10.1016/j.energy.2025.135816","DOIUrl":"10.1016/j.energy.2025.135816","url":null,"abstract":"<div><div>Solar heating has the advantages of low-carbon and clean energy, but its operational performance is significantly influenced by solar radiation, resulting in pronounced randomness and intermittency. Therefore, this study introduces an innovative Active-Passive Hybrid Solar Heating System (A-PHSHS) that incorporates attached sunspace, solar collector, phase change thermal storage device, floor heating, and electric heater, supporting five operational modes. To address the mismatch and lag issues in different mode combinations under Rule-Based Control (RBC), a dynamic operation scheme combining predictive Day-ahead scheduling with Real-time Control (DRC) is proposed. In the day-ahead phase, the scheme plans for thermal storage during valley electricity price periods by predicting solar capacity and the building's thermal demand for the next day. In the real-time control phase, the dynamic switching of operation modes is based on the prediction of the building temperature and feedback. Experimental results show that under DRC, solar utilization rates can reach 40.61 %–46.22 %, with the cost of temperature increase between 3.77 °C/CNY·day and 8.12 °C/CNY·day. Compared to RBC, the indoor average temperature increases by 1.6 °C, solar thermal utilization rate improves by 5.4 %, energy savings reach 24.24 %, and cost savings are 38.40 %.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"323 ","pages":"Article 135816"},"PeriodicalIF":9.0,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying roles of a cleaner energy consumption structure in industrial green transformation: A multi-dimensional perspective considering spatial spillovers and transmission mechanisms","authors":"Kang Gao ,&nbsp;Xu Zhao ,&nbsp;Ran Guo ,&nbsp;Ziyu Guo","doi":"10.1016/j.energy.2025.135776","DOIUrl":"10.1016/j.energy.2025.135776","url":null,"abstract":"<div><div>Investigating the implications of advancing towards a cleaner energy consumption structure (ECS) that prioritizes the use of clean energy is crucial in China's efforts to mitigate pollutant emissions and bolster green productivity, particularly in the context of industrial green transformation (IGT). Regrettably, the intricate nexus between ECS optimization and IGT has frequently been neglected. To address this, our research integrates ECS, energy price, industrial structure, technological progress, and IGT into a unified research framework, thereby quantitatively exploring the influence of ECS optimization on IGT. Our empirical findings unveil positive spatial correlations among the relevant variables across China's provinces. Specifically, the spillover effects of IGT and the demonstration effects of clean energy strategies exert a beneficial external impact on the IGT in neighboring regions. While reducing coal consumption has a minimal impact compared to increasing primary electricity consumption, increasing natural gas consumption plays a notably more significant role in promoting IGT. Furthermore, ECS optimization can indirectly facilitate IGT by intensifying industrial R&amp;D intensity and elevating the share of employment in clean industries. However, distorted energy prices may hinder the direct benefits of ECS optimization for promoting IGT. Notably, when industrial R&amp;D intensity is considered, the relationship between ECS optimization and IGT exhibits a right-tailed U-shaped pattern. As energy price distortion decreases and industrial cleanliness improves, the positive impact on IGT becomes increasingly evident. An important finding is that the ratio of employment in clean industries to those in polluting industries must exceed a critical value of 1.5834 to achieve significant gains.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"323 ","pages":"Article 135776"},"PeriodicalIF":9.0,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the fluid cross-mixing characteristics in tube bundle channels with transverse uneven heat flux distribution","authors":"Zongkun Li ,&nbsp;Guangming Fan ,&nbsp;Jiyun Zhao ,&nbsp;Xiaobo Zeng ,&nbsp;Changqi Yan","doi":"10.1016/j.energy.2025.135794","DOIUrl":"10.1016/j.energy.2025.135794","url":null,"abstract":"<div><div>In the complex system of the Nuclear Power Plant, different reasons cause key equipment such as the core, evaporator, and heat exchanger to have uneven local heat flux distribution perpendicular to the flow direction. This leads to the fluid cross-mixing between the hot and cold zones, which is crucial for calculating local heat transfer and some other issues that are derived from cross-mixing. Therefore, the paper investigated the lateral fluid cross-mixing characteristics under non-uniform heating conditions by numerical simulation to understand the mixing mechanisms and trends. The finding demonstrated that non-uniform heating causes the uneven distribution of the fluid temperature, which in turn produces variations in the fluid viscosity and the flow resistance. Hot side fluid with high temperature has low viscosity and low flow resistance, forcing the fluid of the cold side to flow towards the hot side fluid. Additionally, the fluid cross-mixing model was developed based on the numerical simulation to provide the local velocity distribution for predicting the local heat transfer coefficient and researching other derivative issues by solving the mass, momentum, energy conservation equation, and the deduced lateral momentum equation as a supplementary equation. The model can describe the flow trend along the path, and the calculation error between the model and the Fluent is about −5.16 %∼2.14 %.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"323 ","pages":"Article 135794"},"PeriodicalIF":9.0,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143725042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of the anisotropy of gas diffusion layer on transport characteristics and performance of a PEM electrolysis cell","authors":"Zheng Miao ,&nbsp;Tianxu Jia ,&nbsp;Jinliang Xu ,&nbsp;Chao Xu","doi":"10.1016/j.energy.2025.135795","DOIUrl":"10.1016/j.energy.2025.135795","url":null,"abstract":"<div><div>The anisotropy of the porous materials imposes a substantial effect on the multi-physics transport characteristics in the gas diffusion layer (GDL). The present study developed isotropic and anisotropic three-dimensional, two-phase, non-isothermal models of the Proton Exchange Membrane electrolysis cell (PEMEC). The prediction of electrochemical kinetics is coupled with the mass and heat transfer models to derive the distribution of key parameters and investigate the impact of GDL anisotropy on PEMEC performance. It is found that the GDL anisotropy is mainly caused by the GDL deformation. The deformation reduces GDL porosity and permeability, hindering gases from escaping but enhancing the GDL heat conduction. The temperature of the isotropic GDL is about 4–6 K higher than the deformed GDL. The isotropic PEMEC model also overestimates the cell performance by about 10 % in terms of current/power density at the same cell voltages. Besides, it underestimates the non-uniformity of species concentration and local reaction rates. The local current density in the catalyst layer (CL) for both models shows a bimodal pattern, whereas the deformed GDL model exhibits a more uneven distribution. The parameter-sensitive analysis shows that the smaller contact angle, higher permeability, higher porosity, and higher temperature of the GDL benefit the PEMEC performance.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"323 ","pages":"Article 135795"},"PeriodicalIF":9.0,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143724994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimizing capacity expansion modeling with a novel hierarchical clustering and systematic elbow method: A case study on power and storage units in Spain","authors":"Milad Riyahi,&nbsp;Alvaro Gutiérrez Martín","doi":"10.1016/j.energy.2025.135788","DOIUrl":"10.1016/j.energy.2025.135788","url":null,"abstract":"<div><div>To reduce the computational complexity of Capacity Expansion Models, the planning horizon must be simplified into representative time-periods. Also, to accurately model the expansion of power and storage units, these representative time periods must reveal the mid-term dynamics of the planning horizon. In this paper, a novel hierarchical clustering algorithm is presented that retains the chronology of the original data in creating representative time periods. The proposed algorithm, first, determines the optimal number of clusters with a modified elbow method, enhanced with a stopping criterion to prevent it from running uselessly. The designed stopping criterion works based on percentage variance and runtime to determine the number of clusters systematically. Then, the proposed clustering algorithm employs a novel selection strategy based on the Euclidean distance, k-Medoid, and k-Means to determine the most proper representative vector in each cluster. In this way, it reduces the computational time of capacity expansion models while maintaining the accuracy of final answers. To evaluate its performance, the proposed algorithm is tested on energy data, including demand, photovoltaic, wind, and hydrogen generation, across hourly, daily, and weekly time periods. Also, the performance of the proposed clustering algorithm in selecting the number of clusters and clustering is compared with the results of some well-known methods on accuracy and runtime metrics. Numerical results show that the proposed clustering method selects a more appropriate number of clusters in less computational time than other systematic approaches. Moreover, findings on clustering show that the proposed algorithm achieves the highest accuracy on weekly and daily time periods compared to well-known clustering methods, with the error rate of 118 % and 52 %, respectively. Furthermore, implementation results show that the proposed clustering reduces the computational time of capacity expansion models by 84.81 % and 55.91 % on weekly and daily time periods. Additionally, this study assesses the robustness of the clustering methods through a sensitivity analysis, which shows that the proposed algorithm outperforms the others in this metric, as well.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"323 ","pages":"Article 135788"},"PeriodicalIF":9.0,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Carbon capture through solar-driven CO2 gasification of oil palm empty fruit bunch to produce syngas and biochar","authors":"Saqr A.A. Al-Muraisy ,&nbsp;Srirat Chuayboon ,&nbsp;Lais Americo Soares ,&nbsp;J.G. Buijnsters ,&nbsp;Shahrul bin Ismail ,&nbsp;Stéphane Abanades ,&nbsp;Jules B. van Lier ,&nbsp;Ralph E.F. Lindeboom","doi":"10.1016/j.energy.2025.135805","DOIUrl":"10.1016/j.energy.2025.135805","url":null,"abstract":"<div><div>Oil palm empty fruit bunch (OPEFB) is an abundant organic waste in Malaysia that is often disposed of through field burning. A previous study has shown that solar-driven steam gasification of OPEFB can produce hydrogen-rich syngas with an energy upgrade factor of 1.2 and a carbon conversion efficiency of 95.1 %. Beyond its potential as a biofuel, OPEFB can also act as a carbon sink, capturing photosynthetically stored carbon. This study explores the potential of amplifying OPEFB's negative carbon emissions through solar-driven gasification, using CO₂ as the gasifying agent. In this work, a Central Composite Design (CCD) approach was employed to assess the influence of temperature (1100–1300 °C) and CO₂/OPEFB molar ratio (1.6–3.0) on H₂/CO molar ratio and energy upgrade factor, with a constant OPEFB flow rate of 1.8 g/min. The results demonstrated that at an energy upgrade factor of 1.4, 94.9 % of the total carbon was converted into syngas with a H₂/CO molar ratio of 0.3. The maximum observed net carbon capture yield of 0.4 g C/g OPEFB was achieved at 1300 °C and a CO₂/OPEFB molar ratio of 3.0. The remaining carbon (94.4–95.7 wt %) was converted into biochar with low heavy metal content, which has potential as a soil enhancer.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"323 ","pages":"Article 135805"},"PeriodicalIF":9.0,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143735176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A hybrid technique for grid-tied photovoltaic (PV) systems utilizing a modular multilevel inverter (MMI) topology","authors":"Manimala P ,&nbsp;Sujatha Balaraman","doi":"10.1016/j.energy.2025.135826","DOIUrl":"10.1016/j.energy.2025.135826","url":null,"abstract":"<div><div>This paper proposed a hybrid strategy for grid-tied photovoltaic systems utilizing a modular multilevel inverter (MMI) topology. The novel control strategy is named the Mexican Axolotl Optimization (MAO) and Recalling-Enhanced Recurrent Neural Network (RERNN) technique (MAO-RERNN). The major purpose of this study is to develop a hybrid MAO-RERNN-based control strategy for a 31-level Modular Multilevel Inverter in grid-tied photovoltaic systems to minimize Total Harmonic Distortion (THD) and minimize the switching losses to enhance power quality through optimized switching state prediction and adaptive gate pulse generation. The controller generates gate pulses for level generator switches to produce staircase waveforms of unipolar signals and converts these signals into bipolar using polarity changer switches. MAO adjusts the gate pulses for level generator switches, producing staircase waveforms of unipolar signals, which are then converted into bipolar signals using polarity changer switches. RERNN is employed to predict and optimize the switching states of the inverter, ensuring efficient and accurate control. Implementation in MATLAB validates the performance, demonstrating superior results compared to existing methods. The proposed MAO-RERNN technique achieves a THD of 1.25 % with a 31-level inverter, showcasing its effectiveness in enhancing output quality and system robustness.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"324 ","pages":"Article 135826"},"PeriodicalIF":9.0,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic simulation and predictive control for supercritical water oxidation reactor using reactor network model","authors":"Xiaoge Zhang,&nbsp;Citao Hu,&nbsp;Hao Wang,&nbsp;Youjun Lu","doi":"10.1016/j.energy.2025.135796","DOIUrl":"10.1016/j.energy.2025.135796","url":null,"abstract":"<div><div>Supercritical water oxidation (SCWO) reactor is crucial for hydrogen production through autothermal gasification, where hydrogen oxidation provides heat for supercritical water gasification. However, the dynamic behavior and control strategies of industrial-scale SCWO reactors remain insufficiently explored. A computationally efficient reactor network model was developed to address this. Cold start and open-loop dynamic simulations were conducted to investigate the effects of variations in inlet gasification product mass flow rates, gasification product temperature, and oxygen mass flow rate. Results indicate that the fluid temperature stabilizes within 2 min, while the wall temperature takes approximately 1.1 h. Under slow disturbances, the outlet temperature exhibits quasi-static characteristics. The oxygen mass flow rate significantly influences reactor performance, and a dynamic matrix control (DMC) scheme using it as the control variable is designed to regulate the outlet temperature. The oxygen mass flow rate changes from 450.54 kg/h to 392.25 kg/h and 509.59 kg/h with outlet temperatures set at 850 °C and 950 °C, respectively, within 180 s. A comparison of disturbance rejection performance between DMC and PID controllers reveals that DMC responds faster and reduces overshoot, demonstrating superior performance. This study provides insights into the dynamic behavior and operational flexibility of SCWO reactors in engineering applications.</div></div>","PeriodicalId":11647,"journal":{"name":"Energy","volume":"324 ","pages":"Article 135796"},"PeriodicalIF":9.0,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}