This work aims at the mathematical modeling of a parabolic trough concentrator, the numerical resolution of the resulting equation, as well as the simulation of the heat transfer fluid heating process. To do this, a t...This work aims at the mathematical modeling of a parabolic trough concentrator, the numerical resolution of the resulting equation, as well as the simulation of the heat transfer fluid heating process. To do this, a thermal balance was established for the heat transfer fluid, the absorber and the glass. This allowed us to establish an equation system whose resolution was done by the finite difference method. Then, a computer program was developed to simulate the temperatures of the heat transfer fluid, the absorber tube and the glass as a function of time and space. The numerical resolution made it possible to obtain the temperatures of the heat transfer fluid, the absorber and the glass. The simulation of the fluid heating process was done in one-hour time steps, from six in the morning to six in the afternoon. The results obtained show that the temperature difference between the inlet and the outlet of the sensor is very significant. These results obtained, regarding the variation of the temperatures of the heat transfer fluid, the absorber and the glass, as well as the powers and efficiency of the parabolic trough concentrator and various factors, allow for the improvement of the performances of our prototype.展开更多
The phasor data concentrator placement(PDCP)in wide area measurement systems(WAMS)is an optimization problem in the communication network planning for power grid.Instead of using the traditional integer linear program...The phasor data concentrator placement(PDCP)in wide area measurement systems(WAMS)is an optimization problem in the communication network planning for power grid.Instead of using the traditional integer linear programming(ILP)based modeling and solution schemes that ignore the graph-related features of WAMS,in this work,the PDCP problem is solved through a heuristic graphbased two-phase procedure(TPP):topology partitioning,and phasor data concentrator(PDC)provisioning.Based on the existing minimum k-section algorithms in graph theory,the k-base topology partitioning algorithm is proposed.To improve the performance,the“center-node-last”pre-partitioning algorithm is proposed to give an initial partition before the k-base partitioning algorithm is applied.Then,the PDC provisioning algorithm is proposed to locate PDCs into the decomposed sub-graphs.The proposed TPP was evaluated on five different IEEE benchmark test power systems and the achieved overall communication performance compared to the ILP based schemes show the validity and efficiency of the proposed method.展开更多
Conventional concentrator photovoltaics(CPV)face a persistent trade-off between high efficiency and high cost,driven by expensive multi-junction solar cells and complex active cooling systems.This study presents a com...Conventional concentrator photovoltaics(CPV)face a persistent trade-off between high efficiency and high cost,driven by expensive multi-junction solar cells and complex active cooling systems.This study presents a computational investigation of a novel Multi-Focal Pyramidal Array(MFPA)-based CPV system designed to overcome this limitation.The MFPA architecture employs a geometrically optimized pyramidal concentrator to distribute concen-trated sunlight onto strategically placed,low-cost monocrystalline silicon cells,enabling high efficiency energy capture while passively managing thermal loads.Coupled optical thermal electrical simulations in COMSOL Multiphysics demonstrate a geometric concentration ratio of 120×,with system temperatures maintained below 110℃ under standard 1000 W/m2 Direct Normal Irradiance(DNI).Ray tracing confirms 95%optical efficiency and a concentrated light spot radius of 2.48 mm.Compared with conventional CPV designs,the MFPA improves power-per-cost by 25%and reduces tracking requirements by 50%owing to its wide±15°acceptance angle.These results highlight the MFPA’s potential as a scalable,low-cost,and energy-efficient pathway for expanding solar power generation.展开更多
为支撑数字孪生流域建设与智慧水利发展,针对当前水文模型物理机制薄弱、功能单一、适应性不足及多模型松散耦合效率低等问题,本研究基于中国水利水电科学研究院自主研发的模型体系,研发了集成气象预报-流域产汇流-洪水预报-水库调度全...为支撑数字孪生流域建设与智慧水利发展,针对当前水文模型物理机制薄弱、功能单一、适应性不足及多模型松散耦合效率低等问题,本研究基于中国水利水电科学研究院自主研发的模型体系,研发了集成气象预报-流域产汇流-洪水预报-水库调度全链条、通用化的流域产汇流及洪水预报模型软件平台(Runoff Yield and Concen⁃tration in Watersheds and Flood Forecast Model,Sky-RyCF)。该软件以“自然-社会”二元水循环理论为主线,通过标准化接口深度融合了数值气象预报、分布式产汇流、时空变源产流、一二维水动力洪水演进、社会水循环及多目标调度等核心模块,构建了支持多模型耦合集成与可视化建模的一体化平台。应用结果表明:在永定河“23·7”特大洪水复盘模拟中,卢沟桥洪峰预报值4540 m^(3)/s(实测4650 m^(3)/s),泛区淹没面积模拟误差≤2.0%;在松花江流域水资源评估中,主要水文站月径流模拟Nash效率系数均大于0.7,定量揭示了水资源演变规律。该模型具有物理机制强、功能完备、智能通用等特点,实现了水循环多过程的精细化模拟与业务化应用,为水利“四预”(预报、预警、预演、预案)工作和智慧水利业务提供了核心技术支撑。展开更多
文摘This work aims at the mathematical modeling of a parabolic trough concentrator, the numerical resolution of the resulting equation, as well as the simulation of the heat transfer fluid heating process. To do this, a thermal balance was established for the heat transfer fluid, the absorber and the glass. This allowed us to establish an equation system whose resolution was done by the finite difference method. Then, a computer program was developed to simulate the temperatures of the heat transfer fluid, the absorber tube and the glass as a function of time and space. The numerical resolution made it possible to obtain the temperatures of the heat transfer fluid, the absorber and the glass. The simulation of the fluid heating process was done in one-hour time steps, from six in the morning to six in the afternoon. The results obtained show that the temperature difference between the inlet and the outlet of the sensor is very significant. These results obtained, regarding the variation of the temperatures of the heat transfer fluid, the absorber and the glass, as well as the powers and efficiency of the parabolic trough concentrator and various factors, allow for the improvement of the performances of our prototype.
基金supported by the National Key Research and Development Program of China(2023YFB 2906403).
文摘The phasor data concentrator placement(PDCP)in wide area measurement systems(WAMS)is an optimization problem in the communication network planning for power grid.Instead of using the traditional integer linear programming(ILP)based modeling and solution schemes that ignore the graph-related features of WAMS,in this work,the PDCP problem is solved through a heuristic graphbased two-phase procedure(TPP):topology partitioning,and phasor data concentrator(PDC)provisioning.Based on the existing minimum k-section algorithms in graph theory,the k-base topology partitioning algorithm is proposed.To improve the performance,the“center-node-last”pre-partitioning algorithm is proposed to give an initial partition before the k-base partitioning algorithm is applied.Then,the PDC provisioning algorithm is proposed to locate PDCs into the decomposed sub-graphs.The proposed TPP was evaluated on five different IEEE benchmark test power systems and the achieved overall communication performance compared to the ILP based schemes show the validity and efficiency of the proposed method.
文摘Conventional concentrator photovoltaics(CPV)face a persistent trade-off between high efficiency and high cost,driven by expensive multi-junction solar cells and complex active cooling systems.This study presents a computational investigation of a novel Multi-Focal Pyramidal Array(MFPA)-based CPV system designed to overcome this limitation.The MFPA architecture employs a geometrically optimized pyramidal concentrator to distribute concen-trated sunlight onto strategically placed,low-cost monocrystalline silicon cells,enabling high efficiency energy capture while passively managing thermal loads.Coupled optical thermal electrical simulations in COMSOL Multiphysics demonstrate a geometric concentration ratio of 120×,with system temperatures maintained below 110℃ under standard 1000 W/m2 Direct Normal Irradiance(DNI).Ray tracing confirms 95%optical efficiency and a concentrated light spot radius of 2.48 mm.Compared with conventional CPV designs,the MFPA improves power-per-cost by 25%and reduces tracking requirements by 50%owing to its wide±15°acceptance angle.These results highlight the MFPA’s potential as a scalable,low-cost,and energy-efficient pathway for expanding solar power generation.
文摘为支撑数字孪生流域建设与智慧水利发展,针对当前水文模型物理机制薄弱、功能单一、适应性不足及多模型松散耦合效率低等问题,本研究基于中国水利水电科学研究院自主研发的模型体系,研发了集成气象预报-流域产汇流-洪水预报-水库调度全链条、通用化的流域产汇流及洪水预报模型软件平台(Runoff Yield and Concen⁃tration in Watersheds and Flood Forecast Model,Sky-RyCF)。该软件以“自然-社会”二元水循环理论为主线,通过标准化接口深度融合了数值气象预报、分布式产汇流、时空变源产流、一二维水动力洪水演进、社会水循环及多目标调度等核心模块,构建了支持多模型耦合集成与可视化建模的一体化平台。应用结果表明:在永定河“23·7”特大洪水复盘模拟中,卢沟桥洪峰预报值4540 m^(3)/s(实测4650 m^(3)/s),泛区淹没面积模拟误差≤2.0%;在松花江流域水资源评估中,主要水文站月径流模拟Nash效率系数均大于0.7,定量揭示了水资源演变规律。该模型具有物理机制强、功能完备、智能通用等特点,实现了水循环多过程的精细化模拟与业务化应用,为水利“四预”(预报、预警、预演、预案)工作和智慧水利业务提供了核心技术支撑。
