共查询到18条相似文献,搜索用时 203 毫秒
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《可再生能源》2017,(2):224-231
吸热器的安全高效运行在太阳能热发电系统中起到了至关重要的作用。吸热管中熔盐出口最高温度和平均温度为太阳能热发电系统中吸热器的设计、材料的选择和运行控制提供了重要的科学依据。文章提出了基于最小二乘支持向量机(Least squares support vector machines,LSSVM)的快速预测方法,预测不同工况下吸热管中熔盐出口最高温度和平均温度。为了提高预测精度,利用猫群优化(Cat Swarm Optimization,CSO)算法求解LSSVM方法中的超参数。数值计算结果证实了LSSVM方法是可行的,从而为研究塔式太阳能吸热器的热特性以及运行控制提供一种新的有效方法。 相似文献
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针对太阳能碟式聚光器,设计了一种工质为超临界二氧化碳的圆台形腔式吸热器,建立了腔式吸热器的光热模型。采用蒙特卡洛光线追踪法分析了腔式吸热器的光学特性,并基于相关理论,将热边界条件导入Ansys Fluent软件中,对腔式吸热器的光学特性及流动传热特性进行了计算流体力学(CFD)仿真模拟,得到腔式吸热器内工质出口温度、工质流动压降、光学效率、热效率以及散热损失随着工质进口温度(100~200℃)和太阳光辐射强度(400~1 200 W/m2)的变化规律。结果表明:不同太阳光辐射强度下,吸热器的光学效率基本不变;太阳光辐射强度对腔式吸热器热效率的影响不明显;工质进口温度越高,吸热器的热效率越低;腔式吸热器散热损失中,自然对流散热损失最大,其次是辐射散热损失及导热散热损失。 相似文献
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Systems using molten salt as thermal media have been proposed for solar thermal power generation and for synthetic fuel production. We have been developing molten salt solar receivers, in which molten salt is heated by concentrated solar radiation, in the Solar Hybrid Fuel Project of Japan. A cavity shaped receiver, which is suitable for a beam-down type solar concentration system, was considered. In order to design molten salt solar receivers, a numerical simulation program for the prediction of characteristics of receivers was developed. The simulation program presents temperature distributions of a receiver and molten salt with the use of heat flux distribution of solar radiation and properties of composing materials as input data. Radiation to heat conversion efficiency is calculated from input solar power and heat transferred to molten salt. The thermal resistance of molten salt and the maximum discharge pressure of molten salt pumps were taken into account as restrictions for the design of receivers. These restrictions require control of maximum receiver temperature and pressure drop in the molten salt channel. Based on the incident heat flux distribution formed with a 100 MWth class beam-down type solar concentration system, we proposed a shape of solar receiver that satisfies the requirements. The radiation to heat conversion efficiency of the designed receiver was calculated to be about 90%. 相似文献
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蒸汽发生系统(steam generation system,SGS)是塔式太阳能热发电站的重要组成部分。采用仿真模拟软件Thermoflex对塔式太阳能热发电站的熔盐SGS进行了建模,并基于实际工程数据验证了所搭建模型的准确性。以此为基础,仿真研究了熔盐SGS的换热工质参数(给水温度、主蒸汽温度、主蒸汽压力)对熔盐SGS性能的影响,其中,水侧温度和压力的变化对熔盐侧参数(熔盐流量、熔盐SGS出口的熔盐温度)和换热设备的换热功率均存在较大影响。研究得到的不同换热工质参数对熔盐SGS性能和整个塔式太阳能热发电站的影响规律可为熔盐SGS的设计提供理论依据。 相似文献
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Thermal energy storage(TES) is an important part of concentrating solar power(CSP) plants. The primary advantage of TES in CSP plants is the ability to dispatch electrical output to match peak demand periods and reduce the levelized cost of electricity. The major challenge of the molten salt is its high freezing point, leading to additional complicating freeze protection. This paper presents the experimental results of melting process of a mixed nitrate salt with a melting temperature of 115℃ in a 20 m^3 industrial level tank. Twenty electrical heaters inside the tank are used to heat the salt with a total maximum input power of 240 kW. In order to ensure a safe and fast melting process, the whole process adopted an operating strategy of combining automatic control with manual control. The whole melting process lasted for 314 hours. The salt temperature showed the greatest increase in the first 38 hours. Finally, an economic operation mode of molten salt heat storage tank was obtained. 相似文献
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设计碟式太阳能斯特林机混凝土储热系统,并对熔融盐及混凝土传热过程进行理论分析,对混凝土储释热过程进行模拟,运用多目标遗传算法进行优化,得到以下结论:在释热过程,选取290 ℃为流体出口的有效温度临界值,有效释热时间约2.1 h时,流体出口温度约为563 K,释热效率约为71%;高温混凝土和熔融盐沿着流程方向均存在一个温跃层区域,随着时间的延长,温跃层沿着流程方向逐渐向下游偏移,当温跃层移动到出口处时,熔融盐出口温度开始下降,温跃层占据的长度越小,储热系统效率越高;随着导热系数的增加,释热效率及有效释热时间提高。通过TOPSIS对解集进行重新排序分析,最优工况是蓄热量为2885 MJ、换热系数为672 W/(m·K)及储热效率为87%。 相似文献
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Modelling and simulation of a molten salt loop of a solar tower power plant in a Modelica environment
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CSP(concentrated solar power)系统通过聚焦太阳光进行光热发电,主要工作介质包括导热油及熔盐。由于太阳能的不连续性,为了提供更稳定的能量输出,发展出了采用熔盐为储热工质进行蓄热的系统,该系统同时也提供了与其它能源系统耦合的可行性。该系统的熔盐回路主要由3个部分构成,分别为集热器、高低温储热罐和蒸汽发生器。通过对50 MW塔式太阳能的热发电系统熔盐回路的各个组件的模型进行建立,设计一套与之相应的控制系统,并针对不同工况下,各个组件及整个系统的响应进行了模拟,得出熔盐回路的瞬态响应特性。由于其熔盐回路与熔盐反应堆具有一定的相似性,本研究也可为熔盐反应堆核能综合利用中储能系统提供参考。 相似文献
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太阳能吸热器换热管蓄热数值模拟与试验研究 总被引:2,自引:0,他引:2
对以高温共晶盐LiF—CaF2为相变材料(PCM)和以干空气为工质的相变蓄热系统,采用焓方法建立了以控制体单元为对象的单管相变蓄热模型,并对系统进行了数值分析,得到了循环工质气体出口温度、相变材料容器最高温度和平均壁温等参数的瞬态变化曲线,实验研究了吸热器换热管的蓄傲热性能,分析了工质进口温度、输入热流级工质流量对工质出口温度、PCM容器平均壁温及最高壁温的影响。计算结果和试验表明单元换热管的蓄傲热性能达到了设计要求,试验结果与数值计算吻合良好。 相似文献
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This paper proposes a comprehensive thermodynamic and economic model to predict and compare the performance of concentrated solar power plants with traditional and novel receivers with different configurations involving operating temperatures and locations. The simulation results reveal that power plants with novel receivers exhibit a superior thermodynamic and economic performance compared with traditional receivers. The annual electricity productions of power plants with novel receivers in Phoenix, Sevilla, and Tuotuohe are 8.5%, 10.5%, and 14.4% higher than those with traditional receivers at the outlet temperature of 550°C. The levelized cost of electricity of power plants with double-selective-coated receivers can be decreased by 6.9%, 8.5%, and 11.6%. In Phoenix, the optimal operating temperature of the power plants is improved from 500°C to 560°C by employing a novel receiver. Furthermore, the sensitivity analysis of the receiver heat loss, solar absorption, and freeze protection temperature is also conducted to analyze the general rule of influence of the receiver performance on power plants performance. Solar absorption has a positive contribution to annual electricity productions, whereas heat loss and freeze protection temperature have a negative effect on electricity outputs. The results indicate that the novel receiver coupled with low melting temperature molten salt is the best configuration for improving the overall performance of the power plants. 相似文献