可再生能源下燃煤电站-碳捕集优化调度

燃煤电站集成碳捕集技术在实现碳减排的同时可以提升电站灵活性,帮助电网消纳风光;而可再生能源网络可以提供富余能量来满足碳捕集的需求,提升电站碳捕集系统的经济性能。为此,本文提出了一种可再生能源背景下超临界燃煤电站-碳捕集系统的整体优化调度方法。该方法将深度学习与启发式计算融合,综合考虑机组运行约束和电网功率平衡约束,以降低运行成本和最大消纳风光为目标,对电站-碳捕集系统整体运行优化。结果表明,碳捕集系统的引入可以消纳51%的弃风弃光量,降低35%的碳捕集成本。通过比较,自由捕集率约束模式具有最好的优化调度空间,而平均捕集率约束模式在满足电网指定碳排放要求的同时能够保证良好的经济性。     

一种新型沼气和太阳能互补的分布式能量系统

利用可再生能源,有望进一步提升分布式能量系统的热力性能,降低对化石能源的依赖,从而降低碳排放。本文基于污水处理厂的用能情况,提出一种沼气和太阳能互补的新型分布式能源系统。相比于沼气直接燃烧利用,沼气在新系统中首先参与沼气重整过程,吸收聚集的太阳能转变为更高热值的合成气,进而在冷热电子系统中进行利用。新系统实现了沼气的间接燃烧,减少了沼气燃烧过程的不可逆损失,实现了太阳能品位的提升和化学储存。本文建立了该新系统的动态热力过程模型,以西藏拉萨作为参考地域,得到了系统全年的热力性能。研究表明:相比于沼气和太阳能单独利用系统,新系统多生产299.3 MWh(7%)电能和58.7 MWh(54.9%)冷能,每年节省16340 m3(标况)(11.7%)天然气。本研究为沼气高效利用提供了一种新型技术方案。     

评估、优化分散能源的经济性和环保效益

本文建立了分散能源系统的一般化模型,根据供应与需求瞬时能量平衡的要求和电网分时电价的特点,以分散能源早期可能应用的领域-办公大楼为对象,建立了分散能源年费用最小的优化模型,并对影响分散能源经济性的一些主要因素和分散能源的环保效益进行了分析研究,在电力市场引入竞争机制的条件下,为政府、企业和分散能源的应用者提供决策帮助。     

附加碳税的综合能源系统优化调度分析

针对节能减排的能源转型发展要求,构建了结合可再生能源以及储能装置的综合能源系统模型。引入碳税将CO₂排放的环境问题转换为经济成本问题并建立以经济成本最低为目标函数的优化模型。利用改进的猫群算法对碳税为50 CNY/t的综合能源系统冬夏两季典型日优化调度,对比传统的冷热电三联产(CCHP)系统,综合能源系统的CO₂排放在夏季是CCHP系统的48.93%,冬季为50.86%;节能率在夏季可达到36.33%,冬季能达到23.65%;与没有引入碳税的综合能源系统相比,冬夏两季典型日共减少了40.28%的CO₂排放。对不同碳税下减排效果与经济性的分析,现阶段采用中等的碳税水平(50 CNY/t)更为合理。     

用于120～150℃蒸汽生产的超高温空气源自由活塞斯特林热泵性能研究

现有高温工业蒸汽主要产自于化石燃料燃烧,为减少碳排放和提高能源利用率,需提高可再生能源电力占比,同时开发一种高效、环保的电驱动超高温热泵系统代替传统化石能源蒸汽锅炉。本文针对一种用于产生高温蒸汽的电驱动空气源自由活塞斯特林热泵,基于SAGE软件对其在不同压力、频率和大温差情况下的性能进行了计算研究。研究表明,该系统在大温差供热领域性能优良;在环境温度20℃、供热温度120℃、工作频率45 Hz和平均压力8 MPa的工况条件以及1500 W的热端供热量目标下,系统整机供热系数达2.5,相对卡诺效率63.6%。     

基于遗传算法的光伏–热电耦合系统多目标优化研究

多因素共同作用下的系统优化设计是光伏–热电耦合系统研究的难点之一。本文建立了光伏–热电耦合系统与单一光伏系统的理论模型,以最高耦合效率与相对于单一光伏系统的最大效率差值为优化目标,采用多目标遗传算法,开展了耦合系统优化设计研究。结果表明,最高耦合效率与最大效率差值两个优化目标是负相关的,且其负相关性是由光伏参考效率所导致,需综合考虑系统经济性,确定最高耦合效率和最大效率差值的折中方案,从而获得耦合系统最佳设计。     

一种新型分布式冷热电联产系统热力学分析

本文对一个多能源互补功冷并供的分布式能源系统进行了热力学性能分析。该系统通过太阳能和甲醇热化学互补以及余热驱动的功冷并供,实现了燃料化学能与物理能的综合梯级利用。对系统及其参比系统进行了品位分析,结果表明系统化石能源相对节能率为35.2%,比参比的常规分布式能源系统提高13.5个百分点。本文提出的新型分布式冷热电联产系统,为多能源互补和梯级利用的能源系统集成提供了新方法。     

ORC换热设备结构与操作参数多目标同步优化

随着全球性的能源紧缺和环境问题日益严重,通过充分利用可再生能源和工业余热资源,从而提高能源利用效率是缓解能源和环境问题的重要方式。有机朗肯循环(ORC)是最有应用前景的低品位热能发电技术之一。本文针对ORC系统建立了结构参数和系统操作参数同步优化的换热设备多目标优化模型,采用R245fa为工质和板式换热器,以效率最大和比投资成本最小为目标函数。首先分析了单个变量(蒸发压力、冷凝压力、过热度、蒸发器板间距、冷凝器板间距)对系统性能的影响,然后选取了系统的运行参数(蒸发压蒸发压力、冷凝压力、过热度)和换热器的结构参数(蒸发器和冷凝器的板长、板宽、板间距)九个参数为决策变量,利用遗传算法进行ORC换热设备结构与操作参数多目标同步优化,获得多目标优化的Pareto最优前沿及对应的最优系统运行参数和最佳换热器结构参数组合。     

偏远地区离网混合可再生能源系统建模与优化

本文提出了以太阳能、风能和生物质能为能源输入的离网混合可再生能源系统建模及优化设计框架,综合考虑了偏远农村地区能源供需和用电模式的独特性。对离网混合可再生能源系统进行了建模,并给出其技术经济性评价体系。通过对中国西部某村庄的实例分析,验证了该框架及模型的有效性。结果表明,相比于电网延伸,在偏远农村地区发展离网混合可再生能源系统具有显著的经济、环境效益。     

基于天然气基分布式能源系统智能建筑能源物联网研究

针对常规建筑供能系统存在的不足,充分利用城市既有天然气一次能源供应管网优势,以提高总能系统效率为出发点,本文提出了基于天然气基分布式能源系统智能建筑能源物联网(NDES-SG),并提出了NDES-SG集成基本原则与关键科学问题。为诠释NDES-SG的集成、节能潜力以及系统评价方法,给出了一个范例系统,系统计算结果表明,与常规供能系统相比,NDES-SG实现节能达22.2%。NDES-SG概念为进一步提高能源利用效率与实现新一代的建筑能源供应系统提供了思路。     

A multi-objective design optimization strategy as applied to pre-mixed pre-vaporized injection systems for low emission combustors

This paper presents a multi-objective optimization procedure as applied to the design of the injection system of a Lean Pre-mixed Pre-vaporized combustion chamber. The optimizer drives an Artificial Neural Network in a repeated analysis scheme in order to simultaneously reduce NO_X and CO pollutant emissions. The ANN is trained with a few three-dimensional high resolution reactive viscous flow simulations, carried out with a reliable and robust CFD code. Results, obtained in a four-dimensional state space, demonstrate the validity of the overall procedure with truly moderate computational costs.     

Long-term impacts of battery electric vehicles on the German electricity system

The emerging market for electric vehicles gives rise to an additional electricity demand. This new electricity demand will affect the electricity system. For quantifying those impacts a model-based approach, which covers long-term time horizons is necessary in order to consider the long lasting investment paths in electricity systems and the market development of electric mobility. Therefore, we apply a bottom-up electricity system model showing a detailed spatial resolution for different development paths of electric mobility in Germany until 2030. This model is based on a linear optimization which minimizes the discounted costs of the electricity system. We observe an increase of electricity exchange between countries and electricity generated by renewable energy sources. One major result turns out to be that electric vehicles can be integrated in the electricity system without increasing the system costs when a controlled (postponing) charging strategy for electric vehicles is applied. The impact on the power plant portfolio is insignificant. Another important side effect of electric vehicles is their substantial contribution to decreasing CO₂ emissions of the German transport sector. Hence, electric mobility might be an integral part of a sustainable energy system of tomorrow.     

超临界CO2布雷登循环热电联供系统多目标优化

本文研究了以超临界CO₂布雷登循环为原动机的热电联供系统,对系统主要运行参数进行了分析,得到运行参数对于系统热力学性能和经济性能的影响规律。同时,以一次能源利用率和单位输出成本作为目标函数,采用多目标遗传算法对系统进行了优化;在优化结果的基础上,通过TOPSIS法决策出最优解,并与单目标最优解进行对比。结果表明,透平进口温度、透平进口压力和压缩机进口温度的增大有利于系统效率的提高;作为代价,成本也相应增加。在热电比0~4范围内,尽可能增大热电比能够最大程度上降低系统的单位输出成本,提高能源的利用率。     

燃气-蒸汽联合循环余热回收系统性能研究

燃气发电是我国城市供电的主要形式之一,针对LNG接收站一体的电厂发电模式进行研究,提出一种新型燃气-蒸汽联合循环热电联供系统,利用超临界CO₂布雷顿循环结合有机朗肯循环(ORC)辅助发电,将LNG作为冷源,对烟气余热进行三级利用。通过构建热力学和经济模型,以Aspen Plus软件模拟值为基础,结果表明:在消耗燃料1.704 kg/s(LNG)的条件下,联合循环净发电功率可达45 MW,供热量41.5 MW,余热利用率,热效率和?效率分别为88.50%,52.79%和46.69%。结合热-经济学与参数分析,利用Matlab优化后的最小单位发电成本为0.1529 CNY/kWh。考虑到碳排放价格,供电、供热、供气收益,燃料价格和设备成本,电厂每年的理想收益可达2989.5万元。     

IGCC系统多目标性能统一量化评价准则

本文探讨能够综合评估IGCC系统热力、经济和环保性能的统一量化多目标评价准则,提出采用综合性能指标(CPI)作为评价准则来评估IGCC系统的综合性能。文中对该指标进行深入分析并推导出它与热力特性参数、经济因素及环保特性等关联的系统综合性能指标方程,并在IGCC综合性能的评估与优化中首次将环保变量(CO2回收率)作为系统独立设计变量进行研究。基于新的评价准则,本文开展对回收CO2的新型IGCC系统的实例研究,揭示IGCC系统综合性能与独立设计变量的关联规律,开拓系统多目标综合优化的新方法。本文研究成果为IGCC系统综合性能的评估和设计优化提供了新的思路与准则。     

Comparaison de deux approches d'optimisation. Application à une thermopompe

Comparison between two optimization approaches. Application to a heat pump. An energy flux consists of two parts; an available part, the exergy, and a non-available part, the anergy. The functional diagram of an energetic system is a schematic representation of fluxes for these two compounds. On this diagram, we define the products and ressources of exergy and anergy for each unit of the system as interactions with the external environment and/or with an internal network using two loops: an exergy loop and an anergy loop. This internal circuit could be represented by a server managing the use of exergy and anergy by the various units of the system. We associate to the exergy and anergy fluxes, unit costs defined through an approach called decomposition [1]. This study is concerned with the comparison of results when optimization is based on an objective function, that is one side the investment cost of the system and on the other side the coefficient of performance (COP). In both cases, the work downstream consists in optimizing the unit cost of the main product of each component using the decomposition approach. We will compare the COP, the investment cost, the annual cost and the thermodynamic states of the system.     

Multi-Objective Optimization and Performance Assessments of an Integrated Energy System Based on Fuel,Wind and Solar Energies

The integrated energy system (IES) is an efficient method for improving the utilization of renewable energy. This paper proposes an IES based on fuel, wind and solar energies, following an optimization study focused on determining optimal device capacities. The study included gas turbines, wind turbines, solar photovoltaic panels, ground source heat pumps, absorption chillers/heaters, batteries, and thermal storage. Objectives were incorporated into the optimization model for the overall performance of the IES; these included the primary energy saving rate, annual cost-saving rate, and carbon dioxide emission reduction. Then, the nondominated sorting genetic algorithm II was employed to solve the optimization problem for multiple objectives. Ultimately, the verification and sensitivity analyses of the optimization method were achieved by a case study of hospital buildings in Harbin. The optimization results indicated a primary energy saving rate, annual cost saving rate, and carbon dioxide emission reduction rate of 17.3%, 39.8%, and 53.8%, respectively. The total installed capacity for renewable energy generation accounted for 64.5% of performance optimization. Moreover, the price of natural gas affected the economic indicators of the IES–but failed to impact energy consumption indicators.     

一种基于多目标约束的互连线宽和线间距优化模型

优化线宽和线间距已经成为改善系统芯片性能的关键技术.本文基于互连线线宽和线间距对互连延时、功耗、面积和带宽的影响,提出了基于多目标优化方法实现优化线宽和线间距的思路,并利用曲线拟合方法得到了多目标约束的解析模型.Hspice验证结果显示,该解析模型精度较高,平均误差不超过5%,算法简单,能有效弥补应用品质因数方法的缺陷,可以应用于纳米级互补金属氧化物半导体系统芯片的计算机辅助设计.     

耦合太阳能和地热能的冷热电联供系统优化

天然气和可再生能源互补是一种并行解决环境污染和克服可再生能源不稳定的有效方式,本文提出一种耦合太阳能和地热能的混合冷热电联供(CCHP)系统。基于以电定热(FEL)和以热定电(FTL)运行策略,提出了地源热泵出力比依照逐时电价和季节而变化的运行模式;以一次能源节约率、费用年值节约率以及二氧化碳减排率为目标函数,建立CCHP系统优化模型,运用多目标遗传算法对系统配置及运行策略进行了寻优求解。结果表明:该混合CCHP系统在FEL模式能够实现最优的综合性能.     

Directional Design of Materials Based on Multi-Objective Optimization: A Case Study of Two-Dimensional Thermoelectric SnSe

The directional design of functional materials with multi-objective constraints is a big challenge,in which performance and stability are determined by a complicated interconnection of different physical factors.We apply multi-objective optimization,based on the Pareto Efficiency and Particle-Swarm Optimization methods,to design new functional materials directionally.As a demonstration,we achieve the thermoelectric design of 2D SnSe materials via the above methods.We identify several novel metastable 2D SnSe structures with simultaneously lower free energy and better thermoelectric performance in their experimentally reported monolayer structures.We hope that the results of our work on the multi-objective Pareto Optimization method will represent a step forward in the integrative design of future multi-objective and multi-functional materials.