共查询到18条相似文献,搜索用时 187 毫秒
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基于接收面的光斑等效法,通过MATLAB软件模拟,提出了一种优化接收器表面能流密度分布计算时间的方法,分析单台定日镜和定日镜场的光斑能流密度分布规律。通过研究光斑边缘的能流密度与光斑中心能流密度的比值来分析小尺寸定日镜形成光斑的均匀性。结果表明:提出的计算方法不需要直接算出接收面网格点所有能流密度,对比蒙特卡洛法可缩短68.47%的计算时间;上午随着太阳从东升起,光斑能量主要集中在接收面的中偏右区域;下午随着太阳向西落下,光斑能量主要集中在接收面中偏左区域;采用小尺寸定日镜得到比大型定日镜更加均匀的光斑,在夏至日正午12点时,能流密度均匀性比值可以达到0.238。 相似文献
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提出一种塔式太阳能热发电系统中定日镜调度的方法。根据太阳、定日镜和接收面的光学成像关系,考虑太阳位置、镜面反射率和能见度等因素给出了镜场光能转换效率的计算方法,同时结合定日镜场状态及热力系统所需光功率建立了镜场调度模型。该文将定日镜的调度转化为一个0-1背包问题,设计了一种混合遗传算法来对其求解。采用该调度方法可得到各时刻转换效率最高时所需调用的定日镜数量及其分布,并可调整定日镜瞄准接收靶上分布的目标点,使吸热器上能流分布均匀,降低峰值能流密度,避免过热故障。仿真算例结果表明了该方法的有效性。 相似文献
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碟式聚光器和塔式聚光器均是点聚光系统,为了用月光法间接测量塔式聚光系统的聚光比分布,适宜用聚光稳定的碟式聚光器研究不同月相的光源亮度分布对聚光比分布的影响。主要建立月光下碟式聚光器的聚光比分布计算模型,首先依据拍摄的月相灰度图像建立分块均匀的光源亮度分布模型,再基于三维激光扫描点云数据生成准确的反射镜面形;在光线追迹过程中均匀采样镜面上的反射点,且考虑聚光器的跟踪误差;镜面的光学误差与光源的亮度分布合并为等效的光源亮度分布。模拟聚光比分布与实验聚光比分布的余弦相似度α>95%,光学模型准确性高。 相似文献
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太阳能聚光系统中接收器表面能流密度分布不均匀,会对其光电转换效率以及自身结构的稳定性造成一系列不良影响。为提高接收器能流密度均匀性,文章将微元法与几何构造法相结合,提出Ⅰ型和Ⅱ型两种聚光器模型,利用Trace Pro软件对这两种聚光器的光学特性进行模拟分析,确定出最优模型,进而分析几何聚光比、跟踪误差、安装误差对该模型能流密度分布的影响。结果表明:Ⅱ型聚光器光学特性最优,当几何聚光比为20时,分别以平行光及太阳光入射,接收器上能流密度均匀分布的区域分别占接收器区域的80.18%和75.17%,其光学效率达到99%和95%。此外,随着跟踪误差和安装误差的增大,接收器能流密度均匀分布的区域都减小。本研究对聚光器的优化设计和提高聚光型太阳能系统能源利用效率具有参考意义。 相似文献
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《可再生能源》2017,(2):192-200
优化定日镜场,提高其年聚光效率是降低塔式太阳能电站投资成本的主要途径。以直接蒸汽(DSG)塔式太阳能电站的分离式吸热器为研究对象,为解决现有定日镜场设计过程复杂、耗时较长的不足,利用锥体光学法和径向间距优化法来设计定日镜场。为满足分离式吸热器蒸发段和过热段所需要的热量,采用分配、迭代计算方法得到了分离式吸热器蒸发段和过热段所对应的定日镜场。由于分离式吸热器与定日镜场之间的光热耦合方式比较复杂,因此采用计算精度较高的射线追踪法对分离式吸热器表面的热流分布进行模拟。研究结果表明:通过模拟得到的分离式吸热器所对应定日镜场的布置形式,可使该定日镜场的年聚光效率达到0.652 2,其中分离式吸热器的蒸发段和过热段分别对应了442个和182个定日镜;设计点时刻(春分12:00),分离式吸热器蒸发段和过热段接收的热量分别为35.48 MW和14.19 MW,所获得的热流分布结果可为分离式吸热器的管束布置方式和热学性能计算奠定基础。 相似文献
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In the solar tower power plant, the receiver is one of the main components of efficient concentrating solar collector systems. In the design of the receiver, the heat flux distribution in the cavity should be considered first. In this study, a numerical simulation using the Monte Carlo Method has been conducted on the heat flux distribution in the cavity receiver, which consists of six lateral faces and floor and roof planes, with an aperture of 2.0 m×2.0 m on the front face. The mathematics and physical models of a single solar ray’s launching, reflection, and absorption were proposed. By tracing every solar ray, the distribution of heat flux density in the cavity receiver was obtained. The numerical results show that the solar flux distribution on the absorbing panels is similar to that of CESA-I’s. When the reradiation from walls was considered, the detailed heat flux distributions were issued, in which 49.10% of the total incident energy was absorbed by the central panels, 47.02% by the side panels, and 3.88% was overflowed from the aperture. Regarding the peak heat flux, the value of up to 1196.406 kW/m2 was obtained in the center of absorbing panels. These results provide necessary data for the structure design of cavity receiver and the local thermal stress analysis for boiling and superheated panels. 相似文献
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Solar thermoelectric generators (STEGs) are heat engines which can generate electricity from concentrated sunlight. The non-uniform illumination caused by the optical concentrator may affect the performance of solar thermoelectric generators. In this paper, a three-dimensional finite element model of solar thermoelectric generators is established. The two-dimensional Gaussian distribution is employed to modify the illumination profiles incident on the thermoelectric generator. Six non-uniformities of solar illumination are investigated while keeping the total energy constant. The influences of non-uniform illumination on the temperature distribution, the voltage distribution, and the maximum output power are respectively discussed. Three thermoelectric generators with 32, 18 and 8 pairs of thermocouples are compared to investigate their capability under non-uniform solar radiation. The result shows that the non-uniformity of the solar illumination has a great effect on the temperature distribution and the voltage distribution. Central thermoelectric legs can achieve a larger temperature difference and generate a larger voltage than peripheral ones. The non-uniform solar illumination will weaken the capability of the TE generator, and the maximum output power decrease by 1.4% among the range of non-uniformity studied in this paper. Reducing the number of the thermoelectric legs for non-uniform solar illumination can greatly increase the performance of the thermoelectric generator. 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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Exergetic analysis and economic evaluation of central tower receiver solar thermal power plant
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This article presents the analytical evaluation of a central tower receiver solar thermal power plant with air‐cooled volumetric receiver using exergy analysis. The energetic and exergetic losses as well as the efficiencies of a typical central tower receiver‐based solar thermal power plant have been carried out under the specific operating conditions. The enhancement in efficiency of the plant from the variation in power input to constant power input achieved by thermal storage backup condition has been determined. It is found that the year round average energetic efficiency can be increased from 24.15% to 25.08% and year round average exergetic efficiency can be increased, from 26.10% to 27.10% for the selected location Jodhpur. The unit cost of electric energy generation (kWhe) is found to be INR 10.09 considering 30‐year lifespan of the solar plant along with a 10% interest rate. The present study provides a base for the development of future solar thermal power plants in India. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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针对塔式太阳能热发电站中定日镜跟踪装置的跟踪精度不高、构建成本较大等问题,提出采用将遗传算法的选择机制与吸热塔能量变化的反馈机制相结合的方式对光热电站的太阳能跟踪控制系统进行改进.在光热电站的少数几台定日镜上配备光电检测元件,并以其控制角度为基准控制其他定日镜的角度调整.采用DSP(digital signal processing)为控制核心,完成了跟踪控制器的通讯框架及控制系统的硬件电路设计.实验表明,该方案在保证光热电站整体控制精度的基础上,减少了光电检测元件安装数量和电站构建成本,并保证了视日轨迹跟踪控制时的自动调整能力. 相似文献
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Kevin Ellingwood Seyed Mostafa Safdarnejad Helga Kovacs Jake F. Tuttle 《国际可持续能源杂志》2013,32(10):937-965
ABSTRACTA dynamic model of a tower-driven, hybrid solar gas turbine power plant is presented to highlight the benefits of hybrid operation as well as the development a novel plant configuration to improve solar fraction by leveraging a packed-bed thermal energy storage (TES). Relative to solar-only plant, hybridisation increases solar-to-electric efficiency (STE) by 30%. Introduction of a passive packed-bed TES only leads to slight improvement in solar energy utilisation and displacement of solar load. A novel plant configuration, which utilises a recycle stream to charge TES, is presented to improve solar energy utilisation. The recycle stream gives freedom to manipulate the thermal capacity of flow in the tower collector to control collector exit temperature and direct excess solar energy to TES. Employment of the proposed plant configuration leads to a 10.8% and 11.3% improvement in yearly STE and solar fraction, respectively, relative to a plant not utilising such a control scheme. 相似文献
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辅助锅炉是光热电站快速、安全、高效起停和运行的关键设备,针对某100 MW塔式光热电站辅助锅炉的蒸汽参数和容量选择进行了研究。结果表明:燃煤电站的辅助锅炉选型原则不宜直接应用于光热电站,设置单独小辅助锅炉满足轴封需要以及不同时考虑SGS汽包和除氧器给水箱加热,可以提升机组运行灵活性并减小锅炉容量。这种配置在保证电站成功起停和运行的同时节省了投资,为同类工程提供了参考。 相似文献