Energy Conversion and Management最新文献

{"title":"Deep reinforcement learning-driven wind farm flow control considering dynamic wind","authors":"Hangyu Wang,&nbsp;Shukai He,&nbsp;Jie Yan,&nbsp;Shuang Han,&nbsp;Yongqian Liu","doi":"10.1016/j.enconman.2025.119888","DOIUrl":"10.1016/j.enconman.2025.119888","url":null,"abstract":"<div><div>Mitigating power losses caused by the wake effect is crucial for improving the efficiency of operational wind farms. Wind farm flow control represents a key approach to achieving this objective. However, dynamic wind conditions, including variations in wind speed and direction, along with environmental uncertainties, present significant challenges to effective flow control. To address these challenges, this paper proposes a wind farm flow control method via deep reinforcement learning that considers dynamic wind. Initially, dynamic wind fluctuation characteristics are extracted from LiDAR-measured data, which provides a comprehensive dataset. Subsequently, a flow control method is developed, using dynamic wind as input to maximize wind farm power output through yaw angle adjustments. Finally, the Twin Delayed Deep Deterministic Policy Gradient (TD3) algorithm is introduced to drive a control model for real-time optimization and online learning. The model is capable of addressing uncertainties through experience replay and exploration mechanisms. Simulation results demonstrate that optimization considering mean wind is effective only when the wind direction standard deviation is below 4, whereas optimization considering dynamic wind is effective across all wind conditions. Considering dynamic wind results in a 3.3% improvement in power generation compared to optimization considering mean wind.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"337 ","pages":"Article 119888"},"PeriodicalIF":9.9,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143946721","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":"Energy efficiency improvement for decarbonization in manufacturing industry: A review","authors":"Marius Naumann ,&nbsp;Moritz Ostermann ,&nbsp;Nadja Buchenau ,&nbsp;Jannik Oetzel ,&nbsp;Florian Schlosser ,&nbsp;Henning Meschede ,&nbsp;Thomas Tröster","doi":"10.1016/j.enconman.2025.119763","DOIUrl":"10.1016/j.enconman.2025.119763","url":null,"abstract":"<div><div>The imperative for industrial decarbonization is underscored by political and sustainability requirements. Energy efficiency stands as a foundational pillar in the comprehensive strategy aimed at decarbonizing industrial processes. The heterogeneity and potential interdependencies of energy use in the manufacturing industry necessitates systematic methods and tools, especially in identifying energy efficiency potentials as well as deriving, assessing and prioritizing energy efficiency measures. To address these challenges, this study aims to review existing methods that prioritize decarbonization through holistic and systematic energy efficiency initiatives based on an introduced framework for holistic energy efficiency improvement. Due to the identified lack of holistic approaches in existing methods, this study ultimately proposes directions for future research. This includes the generic and modular modeling of energy demands at different manufacturing levels to identify the technical efficiency potentials, the automated and holistic derivation of energy efficiency measures based on energy efficiency analysis, and multi-criteria assessment and prioritization approach considering interactions between measures. In summary, the development of energy efficiency improvement methods as digitalized and standardized software components for systematic implementation is proposed to support the holistic improvement of energy efficiency and contribute to informed decision-making in the context of industrial decarbonization strategies.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"338 ","pages":"Article 119763"},"PeriodicalIF":9.9,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068545","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":"Absorption-enhanced Haber-Bosch for small-scale green NH3 production. A feasibility study","authors":"Elvira Spatolisano,&nbsp;Davide Figini","doi":"10.1016/j.enconman.2025.119904","DOIUrl":"10.1016/j.enconman.2025.119904","url":null,"abstract":"<div><div>In the context of energy transition, ammonia (NH₃), traditionally used as a fertilizer, represents a promising carbon-free energy vector due to its high hydrogen density (around 17.8 wt%). Nevertheless, the huge carbon intensity of NH₃ synthesis calls for an intensification of the conventional, fossil fuel-based Haber-Bosch process. Flexibility, small-scale plants, modularity and mild operating pressures become fundamental requirements for sustainable NH₃ production, obtained by green H₂ from water electrolysers. To achieve these objectives, this work presents a feasibility study for intensifying the Haber-Bosch process, performed by Aspen Plus® V14 simulation software. Lowering the operating pressure, the NH₃ condensation downstream the reactor is replaced by NH₃ absorption in water. Performances of the novel layout are assessed by means of an energy analysis, based on pinch technology and NH₃ equivalent method. Due to the lower power requirement than the traditional scheme and the absence of thermal energy requirement, the proposed configuration is proved to be a promising pathway towards sustainable and decentralized ammonia, supporting global efforts for transition to a low-carbon future.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"337 ","pages":"Article 119904"},"PeriodicalIF":9.9,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143946678","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":"Continuous bioconversion of CO/CO2 to ethanol through bacterial fermentation in a gas–liquid separation biofilm reactor","authors":"Yun Huang ,&nbsp;Hao Liu ,&nbsp;Wentian Gan ,&nbsp;Xianqing Zhu ,&nbsp;Ao Xia ,&nbsp;Xun Zhu ,&nbsp;Qiang Liao","doi":"10.1016/j.enconman.2025.119932","DOIUrl":"10.1016/j.enconman.2025.119932","url":null,"abstract":"<div><div>Ethanol production by bacterial fermentation using carbon-containing gases is an effective way to achieve the dual carbon goal and green energy production. However, low gas mass transfer efficiency in liquid and insufficient carbon source lead to low ethanol production efficiency. To solve the problem of gas transmission limitation, polyvinylidene fluoride (PVDF), one kind of hydrophobic breathable membrane that can realize gas–liquid separation was used as the attached carrier for the bacterial biofilm in this study. By doing this, carbon-containing gases and liquid culture flow into the bio-reactor respectively from the side of PVDF membrane and biofilm to build. And most of CO/CO₂ mixed gas that passed through the PVDF membrane could be directly utilized by the attached biofilm. The mass transfer coefficient K_La (O₂) reached up to 0.035 s⁻¹, which was nearly 10 times higher than that in the bubbling bio-reactor. The utilization rate of CO gas was improved as high as 50 %. Furthermore, to improve ethanol production, the culture pH was regulated based on the requirements of the mixed bacteria at different growth stages. If the pH in the acidogenic stage was controlled at 6.0 and the later solventogenic stage at 4.5, the maximum ethanol concentration (12.9 g L^-1) was obtained. And the ethanol production rate could stabilize at a high value of 1.08 g L^-1 d^-1 during the continuous fermentation mode. Therefore, pH regulation in the gas–liquid separation biofilm reactor is one of the effective methods to adjust the bacterial metabolic activity and realize stable ethanol production. Moreover, the gas–liquid separation biofilm reactor presents an effective approach to enhance gas–liquid mass transfer and augment ethanol production within the domain of synthesis gas fermentation. Simultaneously, the scalable gas–liquid separation membrane bioreactor also establishes the foundation for the industrialization of synthesis gas fermentation.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"338 ","pages":"Article 119932"},"PeriodicalIF":9.9,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143948524","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":"Parametric analysis and multi-objective optimization of novel desalination-cooling system based on m-cycle and Humidification-Dehumidification desalination technology (HDH)","authors":"Sohrab Hanaei,&nbsp;Mahdi Deymi-Dashtebayaz,&nbsp;Sobhan Ghorbani","doi":"10.1016/j.enconman.2025.119899","DOIUrl":"10.1016/j.enconman.2025.119899","url":null,"abstract":"<div><div>The Maisotsenko Cycle (M−Cycle), recognized for its capability in air conditioning and delivering saturated air in conjunction with humidification-dehumidification (HDH) desalination technology, presents a viable solution for water desalination by leveraging atmospheric moisture. These features make it an attractive option for simultaneous cooling and freshwater production, gaining significant attention in recent research. Given the diverse parameters influencing the performance of the M−Cycle and HDH technology, optimizing the critical variables affecting their efficiency is imperative. This study models a hybrid system integrating the M−Cycle as a supplier of saturated air into an open-air, open-water HDH desalination system, combined with a compression refrigeration cycle functioning as a heat exchanger for hot water. The system also incorporates a finned plate solar air heater (FPSAH) to preheat the air. The integrated system undergoes comprehensive energy, exergy, and exergy-economic analyses. Key parameters, including ambient air temperature, relative humidity, water-to-air ratio, the performance coefficient of the moisture-adsorbing chamber, moisture extraction efficiency, and the outlet water temperature from the heat exchanger, are evaluated for their impact on system performance metrics such as efficiency, coefficient of performance (COP), exergy destruction, and associated costs. A multi-objective optimization employing the TOPSIS method is conducted to determine the optimal dimensions of the air passage channel in the M−Cycle. Additionally, the outlet temperature of the heat exchanger and the water-to-air ratio, as critical variables influencing system performance, are further optimized. The optimization reveals that the optimal dimensions for the air passage channel are a length of 68 cm and a height of 1.98 m. Furthermore, the ideal outlet temperature of the heat exchanger and the water-to-air ratio are identified as 52.59 °C and 2.2, respectively. The analysis indicates that the M−Cycle contributes the highest exergy destruction within the system, highlighting its role in determining overall system performance.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"338 ","pages":"Article 119899"},"PeriodicalIF":9.9,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068543","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":"Optimal dispatch strategy for electricity-heat integrated energy system considering multiple flexibility-enhancing methods","authors":"Zhenxiao Chong ,&nbsp;Lijun Yang ,&nbsp;Yejin Gao ,&nbsp;Xinhui Song","doi":"10.1016/j.enconman.2025.119901","DOIUrl":"10.1016/j.enconman.2025.119901","url":null,"abstract":"<div><div>With the clean transformation of the global energy structure, the exploitation of renewable energy is increasing. However, the adjustable degree of the integrated energy system and the flexibility of the load are still not fully released, leading to a low consumption level of renewable energy. To enhance the operational flexibility of integrated energy system, this paper establishes a flexibility assessment framework. On this basis, a flexible optimal dispatch strategy considering multiple flexibility-enhancing methods for integrated energy system is proposed. Firstly, oriented by the source-load matching degree of the system, a flexibility assessment framework is established by taking the adjustable region and response speed as indexes. Secondly, the hydrogen system and integrated demand response strategy are introduced into the source and load sides of the system as the flexibility-enhancing methods. Thirdly, to release the flexibility of the dynamic differences of the electricity and heat system, a two-stage hybrid timescale optimal model is established with the goals of minimizing the user cost and minimizing the system operation cost, wind curtailment cost heat load loss cost at each stage. In the simulation results, the flexibility-enhancing methods proposed in this paper improve two flexibility indexes by 17.71% and 14.58%, and the operating cost and wind curtailment cost are reduced by 8.00% and 94.20% respectively.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"337 ","pages":"Article 119901"},"PeriodicalIF":9.9,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144068046","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":"Exergoeconomic analysis and multi objective optimization of a nuclear driven integrated cooling and power cycle using response surface regression modeling coupled with genetic algorithm","authors":"Azmain Rashid Raiyan,&nbsp;Samiuzzaman,&nbsp;Yasin Khan,&nbsp;M. Monjurul Ehsan,&nbsp;Md Rezwanul Karim,&nbsp;Sefat Mahmud Siddique","doi":"10.1016/j.enconman.2025.119836","DOIUrl":"10.1016/j.enconman.2025.119836","url":null,"abstract":"<div><div>The current study explores the thermal and economic performance of an innovative combined cooling and power generation system integrating a reheat recompression main compression intercooling Supercritical CO₂ (sCO₂) cycle with a double effect absorption refrigeration cycle. To assess the effects of different input parameters on its performance, a detailed parametric study is conducted. The combined system has been modeled and proposed to harness 600 MW of thermal energy from the nuclear reactor. The dataset extracted from thermodynamic and exergoeconomic models has been utilized for response surface regression modeling (RSM) and its accuracy has been evaluated using different error matrices. Finally, multi-objective optimization has been conducted integrating the quadratic regression model with genetic algorithm (GA) on three objective functions: energy utilization factor (EUF), exergy efficiency (η_ex) and total product unit cost (c_p,tot) which provided 84 Pareto optimal datasets. Genetic algorithm and LINMAP are incorporated to select an ideal operating condition from the pareto optimal solutions. Single point optimization revealed that the novel cycle has a maximum EUF, and second law efficiency of 69.12 % and 77.07 % respectively with a minimum unit cost of 9.46 $/GJ. The cycle generates 400.4 MW of power and 116.2 MW of evaporative cooling when operated at basic design point. Key findings from this work demonstrate substantial performance enhancements in the integrated cycle compared to the conventional ones integrating the sCO₂ cycle with a single effect ARS. This research could significantly advance the harnessing of nuclear energy by optimizing advanced combined power and cooling cycles. Improving system efficiency and economic feasibility could pave the way for major advancements in nuclear power generation by introducing new areas for research and innovation.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"337 ","pages":"Article 119836"},"PeriodicalIF":9.9,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143942144","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":"A novel linear search-linear programming method for non-convex multi-objective sizing of standalone microgrids","authors":"Zishan Yin ,&nbsp;Jiashu Jin ,&nbsp;Linghong Zeng ,&nbsp;Xiyun Tang ,&nbsp;Zhuo Wang ,&nbsp;Xi Li","doi":"10.1016/j.enconman.2025.119849","DOIUrl":"10.1016/j.enconman.2025.119849","url":null,"abstract":"<div><div>Both the increased utilization of photovoltaic (PV) and the consequent expansion of energy storage, leading to higher costs, are critical factors in the development of a techno-economic microgrid. To address this trade-off, optimal sizing design of a multi-energy microgrid is essential. This paper proposes a novel linear search-linear programming method for optimizing the sizing of microgrids with diverse energy storage systems, including battery energy storage systems (BESS) and hydrogen energy storage systems (HESS). The method minimizes both the non-linear and non-convex life cycle cost and the PV curtailment rate. Simulation results demonstrate the feasibility and superiority of the proposed method, achieving enhanced computational efficiency: 52 times faster for PV/HESS microgrids, 124 times for PV/BESS, and 5 times for PV/HESS/BESS. Moreover, more comprehensive and accurate optimal configurations were identified, including 4289 PV units for both the PV/BESS and PV/HESS/BESS microgrids, and 6239 PV units along with 37 fuel cell units for the PV/HESS microgrid. Based on the advanced optimization outcomes, a techno-economic analysis shows that the PV/HESS/BESS microgrid optimally combines the advantages of both HESS and BESS, substantially improving overall system performance.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"337 ","pages":"Article 119849"},"PeriodicalIF":9.9,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143946720","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":"Comparative study of supercritical CO2 brayton cycles for solar towers plants in arid climates: Design and off-design performance","authors":"Meryame Soumhi ,&nbsp;Yassine Zalim ,&nbsp;Zakia EL Ahmadi ,&nbsp;Fayrouz El Hamdani ,&nbsp;Hicham Bouzekri","doi":"10.1016/j.enconman.2025.119902","DOIUrl":"10.1016/j.enconman.2025.119902","url":null,"abstract":"<div><div>Concentrated Solar Power plants offer significant potential for sustainable energy generation, but their efficiency is often constrained by extreme ambient conditions and limited water resources in arid climates. This study examines the design and off-design performance of simple and recompression supercritical CO₂ Brayton cycles across various power scales, focusing on their integration into CSP tower plants in Morocco. The objective is to evaluate the impact of scaling on cycle efficiency, turbomachinery design, compare the performance of both cycles and identify optimal parameters to enhance performance in challenging environments. A detailed parametric sensitivity study of both cycle configurations was conducted to determine the optimal total recuperator conductance for improving cycle efficiency. For model validation, the results were compared with the National Renewable Energy Laboratory model. The solar field design was developed using the System Advisor Model at large scale. Off-design conditions were analyzed to assess the effects of varying ambient conditions and heat transfer fluid temperatures on cycle performance. The design analysis demonstrates that scaling up significantly improves thermal efficiency for both cycle configurations. The study identified optimal recuperator conductance values for simple and recompression cycle, leading to thermal efficiencies of 40.1 % and 45 %, respectively. Validation against the SAM model showed strong agreement, with relative errors under 3 %. Solar field design results indicate that the recompression cycle requires 12 % less heliostat field area than the simple cycle. Additionally, off-design analysis revealed that the simple cycle is more adaptable to arid climates, maintaining similar efficiency as recompression cycle at higher ambient temperatures.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"337 ","pages":"Article 119902"},"PeriodicalIF":9.9,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143936498","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":"Conversion of an existing diesel depot into an on-site hydrogen refuelling station for heavy-duty vehicles: A multi-objective optimisation","authors":"Antonio Sgaramella,&nbsp;Lorenzo Mario Pastore,&nbsp;Gianluigi Lo Basso,&nbsp;Livio de Santoli","doi":"10.1016/j.enconman.2025.119916","DOIUrl":"10.1016/j.enconman.2025.119916","url":null,"abstract":"<div><div>Transport is one of the energy segments belonging to the so-called hard-to-abate sectors. Despite several EU directives promote its decarbonisation, heavy-duty mobility still shows increasing emissions, due to the continuous raise in road freight activity and reliance on low-efficiency internal combustion engines powered by fossil fuels. Hydrogen fuel cell electric trucks represent one of the most valuable solutions for the long-haul transport segment greening. However, the current lack of economy of scale and paucity of refuelling infrastructure represent a significant hint to the widespread deployment of hydrogen mobility. This paper presents a design methodology for converting a diesel depot into an on-site green hydrogen refuelling station dedicated to fuel cell electric trucks. To do so, 150 eligible capacities of photovoltaic plant, electrolyser and low-pressure storage system have been dynamically simulated in the MATLAB/Simulink environment. Thereafter, by means of a multi-objective optimization, based on Pareto Front and Utopia Point, the optimal solutions have been identified. By maximising the hydrogen production and simultaneously minimising the levelized cost of hydrogen, solar energy excess and compressor energy utilisation the components size can be determined. The main outcomes of this study show that the most suitable electrolyser/photovoltaic plant capacity ratio is 44.1%. By comparing on-site with off-site hydrogen refuelling stations, the hydrogen production, distribution and transmission cost equal to 7.70 €/kg is the break-even point between the two stations typologies. Converting diesel pumps into hydrogen refuelling stations can reduce capital expenditure by 30–50% compared to greenfield hydrogen stations.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"337 ","pages":"Article 119916"},"PeriodicalIF":9.9,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143936472","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}