Energy Conversion and Management最新文献

{"title":"The effect of impurities in captured CO2 on the distribution of liquefaction and purification costs","authors":"Rikke C. Pedersen ,&nbsp;Ebbe H. Jensen ,&nbsp;Isaac A. Løge ,&nbsp;Brian Elmegaard ,&nbsp;Jonas K. Jensen","doi":"10.1016/j.enconman.2025.119839","DOIUrl":"10.1016/j.enconman.2025.119839","url":null,"abstract":"<div><div>Carbon Capture, Utilisation, and Storage is an unavoidable tool in reducing greenhouse gas emissions from energy and industrial sectors. Shared transport infrastructures are necessary to implement the technology on large-scale at acceptable costs. The CO₂ quality varies with different emitters, and if these should use a common infrastructure, it is important to understand the economic effects of the impurities throughout the Carbon Capture value chain. The captured CO₂ is typically purified and liquefied using a conditioning system prior to transportation. This study performs an exergoeconomic analysis of a conditioning process considering four different feed gas compositions. The system was modelled using a chemical process modelling tool, and energy and economic analyses were performed. Exergy was used as a basis for distributing the costs associated with reaching the liquid state and the correct quality, respectively. It was found, that the various feed gas compositions did not significantly affect the costs directly associated with liquefaction, which remained at 18<!--> <!-->EUR/(t<!--> <!-->CO₂) to 21<!--> <!-->EUR/(t<!--> <!-->CO₂). Removal of the incondensable gases accounted for between 0.1<!--> <!-->EUR/(t<!--> <!-->CO₂) to 18.7<!--> <!-->EUR/(t<!--> <!-->CO₂) and depended on the feed gas composition. Higher costs associated with water removal through cooling and higher losses during the distillation process were observed when more impurities were present in the feed gas. This resulted in increased purification costs. The results show that quality requirements from off-takers and transport operators can impose economic drawbacks for emitters. It emphasises the relevance of considering which CO₂ sources are best suitable for different off-takers when impurity constraints are imposed.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"336 ","pages":"Article 119839"},"PeriodicalIF":9.9,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143912002","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":"Large-scale fluidized-bed CH4 pyrolysis reactor for simultaneous COx-free H2 and carbon production: Multi-objective optimization and artificial intelligence modeling of different process schemes","authors":"Ali Bakhtyari ,&nbsp;Masoud Mofarahi ,&nbsp;Adolfo Iulianelli","doi":"10.1016/j.enconman.2025.119885","DOIUrl":"10.1016/j.enconman.2025.119885","url":null,"abstract":"<div><div>The present study is devoted to the development, multi-objective optimization, and artificial intelligence modeling of turquoise H₂ and carbon production through the thermal decomposition of CH₄ also known as pyrolysis. With a kinetic model of reaction and deactivation on the Fe/Al₂O₃ catalyst particles, a mathematical model was derived for a fluidized-bed pyrolysis reactor with a perfectly mixing continuous stirred tank reactor assumption, which is then applied to a genetic algorithm optimization procedure to explore the best performance of the two reactor designs (adiabatic and well-heated). The optimization strategy included two plans for the best operating conditions and processing time. In both optimization plans, the well-heated reactor was superior in terms of higher conversions and product yields, as well as more stable catalysts. This was managed due to the instantaneous heating of the reaction area by molten salt flowing in the shell side of the reactor. The mathematical model was in the next section combined with an artificial intelligence computation approach inspired by neural networks. Extended databanks that included 3840 runs at varied operating conditions in each pyrolysis reactor were then analyzed by Pearson approach to determine the effective input variables and construct the input layer of single- and double-layer perceptron neural networks. The impacts of train function and hidden layer(s) size were also investigated rigorously. Although single-layer neural networks failed to describe the systems in question efficiently, the double-layer modes that benefitted from the <em>trainbr</em> and <em>trainbfg</em> functions could represent the outputs (average temperature, conversion, H₂ yield, and carbon yield) of both systems precisely. Statistical parameters, errors analysis, as well as kernel density and histogram analyses, revealed that the calculations of best models can be dependable. Through a comparison between the models’ outputs and the target variables, it was also revealed that the double-layer network can detect even very small alterations in the operating variables.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"336 ","pages":"Article 119885"},"PeriodicalIF":9.9,"publicationDate":"2025-05-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143907011","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 3D-printed full-soft regenerative elastocaloric cooler","authors":"Kun Wang,&nbsp;Kurt Engelbrecht,&nbsp;Christian R.H. Bahl,&nbsp;Rasmus Bjørk","doi":"10.1016/j.enconman.2025.119811","DOIUrl":"10.1016/j.enconman.2025.119811","url":null,"abstract":"<div><div>Elastocaloric cooling employing soft elastomers represents a path to reduce the climate impacts associated with conventional vapor compression refrigeration. The use of soft elastomers enhances efficiency, flexibility, and cost-effectiveness of elastocaloric systems, while significantly reducing the driving force for promising low-stress elastocaloric cooling. This study presents fully 3D-printed soft elastomeric regenerators featuring parallel plate and square channel designs, operating under 5.5–7.7 MPa. The 3D-printed elastomer exhibits an adiabatic temperature change of 2.3 K upon unloading at 600% strain. The 3D-printed elastomers were used to build a regenerative elastocaloric cooler featuring automatic fluid compensation to address large strain-induced volume changes in fluid channels, which resulted in enhanced cooling performance. The cooler achieves a 4.7 K temperature span (regeneration ratio: 2.04) in a square-microchannel regenerator and delivers a maximum specific cooling power of 1850 W/kg. Utilizing additive manufacturing for rapid prototyping of microchannel regenerators, this work demonstrates a scalable and commercially viable approach to low-force elastocaloric cooling.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"336 ","pages":"Article 119811"},"PeriodicalIF":9.9,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904352","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":"Optimized energy management in Grid-Connected microgrids leveraging K-means clustering algorithm and Artificial Neural network models","authors":"Peter Anuoluwapo Gbadega,&nbsp;Yanxia Sun,&nbsp;Olufunke Abolaji Balogun","doi":"10.1016/j.enconman.2025.119868","DOIUrl":"10.1016/j.enconman.2025.119868","url":null,"abstract":"<div><div>The increasing integration of renewable energy sources (RESs) in grid-connected microgrids necessitates advanced energy management strategies to enhance efficiency, reliability, and sustainability. This study proposes an optimized energy management framework leveraging the One-to-One-Based Optimizer (OOBO) for microgrid scheduling, combined with K-means clustering and Artificial Neural Networks (ANNs) for load forecasting. The proposed method dynamically schedules distributed energy resources (DERs), battery energy storage systems (BESS), and diesel generators while minimizing operational costs and carbon emissions. Simulation results demonstrate that the OOBO-based optimization achieves a 20–48% reduction in operational costs and a 25–38% decrease in carbon emissions, outperforming conventional methods such as Particle Swarm Optimization (PSO), Genetic Algorithm (GA), and Differential Evolution (DE). The comparative analysis highlights the superior convergence speed of OOBO, reducing computational time by 30–45%, making it suitable for real-time applications. Furthermore, the study evaluates three scenarios: reliance solely on a diesel generator, optimization without BESS, and optimization with BESS, where BESS integration led to a 38% reduction in emissions compared to diesel generator-only configurations. The novelty of this work lies in the synergistic integration of OOBO, AI-driven forecasting models, and adaptive resource scheduling, ensuring optimal cost savings and energy efficiency. The results confirm the scalability and robustness of the proposed framework, making it a promising solution for future multi-microgrid and multi-energy system applications. These findings provide a strong foundation for sustainable energy transitions, reducing dependence on fossil fuels and enhancing grid stability.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"336 ","pages":"Article 119868"},"PeriodicalIF":9.9,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143904300","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":"On the performance of a compact-array OWC device with airflow-pathway shared configurations: An experimental study","authors":"Zhen Liu ,&nbsp;Xiaoxia Zhang ,&nbsp;Heqiang Ni ,&nbsp;Lei Ding ,&nbsp;Ziqian Han","doi":"10.1016/j.enconman.2025.119862","DOIUrl":"10.1016/j.enconman.2025.119862","url":null,"abstract":"<div><div>Building on foundational studies of the compact oscillating water column array device called the “Ring-type AIsled Networking BDB-OWC”, this study proposes merging modules to share common chambers and airflow pathways, aiming to enhance performance and reduce costs by minimizing turbine requirements. A 1:10 scale model was tested under four merging configurations in regular wave scenarios within a wave tank. Key metrics − free-surface elevations, air pressure variations in merged versus individual modules, airflow rates through orifices, and energy-harvesting performance − were compared. Time-history data revealed phase differences and their influences on performance, while statistical analyses highlighted distinctions across merging plans and unmerged configurations. Experimental results demonstrate that merging alters pneumatic damping characteristics, influencing free-surface elevations and air volume transport. Merging near-end modules facing forward incident waves enhanced overall performance, whereas merging far-end modules under oblique waves reduced power capture. The merged modules achieved a peak capture width ratio of 0.38 under possible underestimations from the incident wave power calculations, 1.46 times that of individual modules.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"335 ","pages":"Article 119862"},"PeriodicalIF":9.9,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143908334","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":"Maximizing solar photovoltaic efficiency with Mist Cooled sandwich bifacial panels under extreme hot climate conditions","authors":"Zafar Said ,&nbsp;Fahad Faraz Ahmad","doi":"10.1016/j.enconman.2025.119865","DOIUrl":"10.1016/j.enconman.2025.119865","url":null,"abstract":"<div><div>A novel sandwich bifacial photovoltaic panel system with integrated mist cooling is proposed to enhance energy generation per unit area in photovoltaic installations. Traditional bifacial photovoltaic panels effectively utilize ground reflections. Still, they often encounter high operating temperatures, leading to thermal degradation. This new design features a back-to-back arrangement of two mono-facial photovoltaic panels, incorporating mist cooling between them. This innovative design significantly increases energy density while effectively mitigating thermal degradation. Experimental investigations were conducted under actual outdoor conditions representative of extremely hot climates, with the United Arab Emirates chosen as a specific case study. The experimental results show that the energy yield from the sandwich bifacial photovoltaic panel was 26.05 % higher than that of a standard monofacial photovoltaic panel operating without cooling. For the rear-facing photovoltaic surface temperature, a reduction of 34.03 % is observed for the front surface, and 14.81 % is recorded for the rear surface with mist cooling. The corresponding temperature reduction for the front-facing panel was 20.48 % on a sunny day and 13.18 % on a cloudy day, and the reduction in the rear surface was 9.61 % and 16.02 %, respectively. Such thermal enhancements are expected to yield power gains of 37.14 % on sunny days and 46.02 % on cloudy summer days compared to conventional mono-facial photovoltaic panels. The system demonstrated an annual energy output of 45.34 kWh/m² more than mono-facial systems, corresponding to an annual economic gain of $5.48/m². This approach represents one very efficient and practical way to improve the photovoltaic performance without compromising the already-occupied ground surface.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"335 ","pages":"Article 119865"},"PeriodicalIF":9.9,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143900102","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 analysis of scenarios of data center waste heat utilization for district heating networks of different generations","authors":"D. Romanov,&nbsp;I. Chakraborty,&nbsp;S. Holler","doi":"10.1016/j.enconman.2025.119856","DOIUrl":"10.1016/j.enconman.2025.119856","url":null,"abstract":"<div><div>The growth of global telecommunication infrastructure offers significant opportunities for harnessing data center waste heat. This study focuses on analyzing and comparing several scenarios — business as usual (BAU), data center waste heat recovery (WH), and WH complemented by a shallow borehole thermal energy storage addressing the mismatch between heat demand and waste heat production (WH + BTES) — under various district heating (DH) temperatures representing different generations of DH networks. The north campus in Göttingen serves as a case study. We used a customized Python model, incorporating the pygfunction package and a regression-based heat pump model, to assess the thermal response factors (g-functions) of geothermal borehole fields and to perform the analysis. The results demonstrate that around 70 % of the considered heating and cooling demand can be covered in the WH scenario and additionally about 20 % in the WH+BTES scenario. Currently, the WH scenario is economically most promising, while the WH+BTES scenario allows for higher CO₂ savings. The sensitivity analysis further indicates that storing waste heat could become economical if the BTES capital cost were reduced by 35 % and the ratio of DH price to electricity price increased to 2.5 times the current value. For the WH scenario, the range of marginal waste heat prices was determined using Monte Carlo simulations. The average values obtained are 48, 56, 90, 93 €/MWh_wh for the DH design supply temperatures of 120, 95, 70, 48 °C, respectively. Thus, low-temperature district heating operators can expect larger profits if waste heat prices are constant for all network temperatures.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"334 ","pages":"Article 119856"},"PeriodicalIF":9.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143895555","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":"Multi-degree-of-freedom decoupled mechanism for improving energy harvesting performance of wave energy converter","authors":"Yongxing Zhang ,&nbsp;Zhicong Huang ,&nbsp;Jing Bian ,&nbsp;Junwei Liu ,&nbsp;Ning Su","doi":"10.1016/j.enconman.2025.119850","DOIUrl":"10.1016/j.enconman.2025.119850","url":null,"abstract":"<div><div>The multi-degree-of-freedom wave energy converter (MDWEC) has attracted much attention due to its potential to efficiently harvest wave energy. However, current designs of MDWECs seldom consider coupled motions between the floating body and the power take-off (PTO), resulting in a loss of energy harvesting efficiency. To bridge this research gap, this paper explores the decoupled mechanism of active drive mechanical structures used for the MDWEC energy harvesting scenario. This decoupled mechanism enables the operating axes of PTOs to align one-to-one with the motion degree-of-freedom (DOF) of the floating body, thereby overcoming the energy harvesting efficiency limitations of the MDWEC caused by the coupled motion. To illustrate this idea, a novel multi-DOF decoupled wave energy converter (MDD-WEC) is presented according to real wave site conditions. A multi-physical-domain numerical model is developed. According to the Froude criterion, the reduced-scale prototype is constructed, and the numerical model test is performed in a wave tank. The proposed structure’s motion response amplitudes obtained from wave tank experiments and numerical simulations under two irregular wave conditions showed relative errors below 5 %, confirming the numerical model’s accuracy. Based on this, multi-PTO parameter analysis is subsequently performed to reveal the effects of different PTO configurations on the energy harvesting performance of the MDD-WEC. Benefiting from this characteristic, each PTO in the MDD-WEC can be independently optimized to absorb more wave energy according to wave conditions. The performance comparison results demonstrated that, compared with the point absorber WEC and the parallel configuration WEC with multi-DOF, the proposed MDD-WEC increases the capture width ratio (CWR) by 72.5 % and 39.3 % under regular wave conditions, respectively, and by 60.8 % and 32.9 % under irregular wave conditions.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"334 ","pages":"Article 119850"},"PeriodicalIF":9.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143895556","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":"Machine learning optimization of integrating an advanced thermal-electrochemical plant with an oxy-biogas fuel plant employing a CO2 capture process","authors":"Milad Feili ,&nbsp;Pejman Nourani ,&nbsp;Maghsoud Abdollahi Haghghi ,&nbsp;Ammar M. Bahman","doi":"10.1016/j.enconman.2025.119871","DOIUrl":"10.1016/j.enconman.2025.119871","url":null,"abstract":"<div><div>This study addresses boosting biogas utilization through oxy-fuel combustion and integrating an innovative multigeneration system. This system allows advanced thermal-electrochemical integration for electric power, cooling, heat, and liquefied hydrogen generation. This approach reduces energy loss and incorporates a CO₂ capture unit. Hence, the integrated subsystems include an oxy-biogas combustion power plant, a supercritical-CO₂ power plant, an organic Rankine cycle, an NH₃-H₂O combined coolant and power cycle, a solid oxide electrolysis cell, and a Claude hydrogen cycle. The study presents a complete examination covering thermodynamic, sustainability, and economic perspectives and detailed parametric assessments, showing the combustion temperature as the most influential parameter. Subsequently, an optimization process is conducted, employing a multi-objective strategy utilizing machine learning techniques based on artificial neural networks and multi-objective grey wolf optimization. Considering the tri-objective scenario with the exergy efficiency, net present value, and total unit cost of products as objective functions, their optimal values are calculated at 47.75 %, 17.72 M$, and 28.13 $/GJ, respectively. Under the tri-objective optimization scenario, the total exergy destruction equals 4630 kW, with the combustion chamber as the most important contributor. Also, the sustainability index and payback period are found at 1.92 and 17.7 M$, respectively. Besides, these conditions exhibit liquefied hydrogen output of 2.9 m³/day, costing 3.37 $/GJ. This research highlights that the integration of oxy-biogas fuel combustion with the designed multigeneration system can enhance biogas utilization, achieving improved thermodynamic efficiency and economic performance while supporting the sustainable production of high-value energy products.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"335 ","pages":"Article 119871"},"PeriodicalIF":9.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143900101","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":"Solar-driven artificial tree desalination with enhanced stability and performance via structural and materials optimization","authors":"Zihao Zhu ,&nbsp;Yahong Yu ,&nbsp;Yingzong Liang ,&nbsp;Xianglong Luo ,&nbsp;Jianyong Chen ,&nbsp;Zhi Yang ,&nbsp;Ying Chen","doi":"10.1016/j.enconman.2025.119847","DOIUrl":"10.1016/j.enconman.2025.119847","url":null,"abstract":"<div><div>This study presents a novel solar-driven desalination artificial tree device designed to enhance sustainable freshwater production through a series of structural and material optimizations. A well-tuned draw solution is developed to improve system stability, enabling effective long-term operation with an evaporation layer featuring nanopores smaller than 100 nm. This enhancement allows for the use of a thinner anodized aluminum oxide membrane, reducing thermal resistance and facilitating efficient mass and heat transfer. The device structure is optimized into a compact, horizontal configuration, with a reduced air gap thickness to minimize vapor diffusion resistance and maximize sunlight absorption from multiple angles. As a result, the five-stage device achieves a steady-state water yield of 1.78 kg m^-2h^-1 under 1 kW m^-2 light intensity with a 3.5 wt% NaCl solution—a 17.88% improvement over the pre-optimization design. The device exhibits stable freshwater production over multiple cycles, with an ion rejection rate approaching 99.9% and salinity levels well below the WHO.</div></div>","PeriodicalId":11664,"journal":{"name":"Energy Conversion and Management","volume":"334 ","pages":"Article 119847"},"PeriodicalIF":9.9,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143895779","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}