一种定日镜场有效镜面面积的评估方法

以定日镜轮廓向地平面投影法计算定日镜镜面的阴影与遮挡损失。定日镜有效面积还受镜面破损、运行故障比例和镜面遮盖损失的影响,因此引入修正因子,得出一种定日镜场总有效镜面面积的评估方法。以宿迁200 kW塔式太阳能光热电站的定日镜场为例,计算定日镜场在4个典型日的阴影与遮挡效率,进而得到定日镜场的平均有效镜面面积。     

塔式电站定日镜场布置范围的理论分析

采用MALAB编程,计算了余弦效率、大气透过效率以及吸热器开口平面上的截断效率,并将这三项效率的乘积定义为地面利用效率用于限制定日镜场的布置范围,进而分析了一些参数对定日镜场布置范围的影响。分析结果表明,地面利用效率可有效限定定日镜场的布置范围。与接收塔光学高度和吸热器开口的倾斜角度相比,吸热器的开口尺寸和定日镜的整体误差大小在很大程度上限定了定日镜场的布置范围。要增大电站容量,必须增大吸热器开口尺寸。而提高定日镜的整体性能不但可提高定日镜场的光学效率,也可有效扩大定日镜场的布置范围,增大电站容量。     

塔式太阳能热发电镜场中余弦效率仿真研究

参考eSolar塔式发电站中的矩形定日镜场,通过参数设计得到密集的轴对称交错排列布置方案;建立了余弦效率的数学模型,对一天中不同时刻的太阳入射角变化趋势进行了仿真,得出位于接收塔南北区域余弦效率状况;对矩形定日镜场的余弦效率分布做了进一步研究。仿真结果验证了太阳入射角的变化趋势,并得出塔的高度对余弦效率的影响。     

反射塔底式太阳能集热装置及镜场分析

提出了塔式太阳能热发电站反射塔底式集热装置,并与传统的塔式太阳能集热装置进行了能量损失分析比较,对反射塔底式太阳能集热装置的镜场进行了建模分析。通过对反射塔底式集热装置模型及对定日镜场的分析,显示了定日镜对塔顶二次反射器面积效应的影响,推荐了定日镜的形状参数。     

塔式太阳能热发电系统镜场调度方法的研究

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。     

塔式太阳能电站聚光镜场的土地利用率研究

塔式太阳能热发电站的聚光镜场大多是由按一定规律排列的矩形定日镜组成,在相邻定日镜间无机械碰撞的情况下,聚光镜场的最大土地利用率仅为58%。文章提出了选用规则交错排列的聚光镜场布置方案,建立不同形状定日镜的土地利用模型,并计算出不同情况下的最大土地利用率。通过仿真得出,矩形定日镜和六边形定日镜在一定长宽比时可获得最大土地利用率,其中六边形定日镜的土地利用率最高,约为100%。     

太阳能热发电系列文章(5)塔式太阳能热发电的定日镜

定日镜是一种由镜面(反射镜)、镜架(支撑结构)、跟踪传动机构及其控制系统等组成的聚光装置,用于跟踪接收并聚集反射太阳光线进入位于接收塔顶部的集热器内,是塔式太阳能热发电站的主要装置之一,如图1、图2所示。     

定日镜光斑动态漂移特性的研究

以塔式太阳能热发电系统中的定日镜为研究对象,首先提出一种基于光学反射原理的定日镜反射光斑中心计算方法;然后在理想情况下分析不同塔高、不同位置、不同时刻定日镜光斑中心点的动态变化规律,进一步考虑跟踪误差对定日镜反射光斑漂移特性的影响;最后对矩形全镜场中春分日不同时刻的光斑动态漂移特性进行仿真计算并得出相应结论,为有效实现定日镜的追日聚光跟踪控制和参数校正,提高追日跟踪精度及全境场的聚光效率提供理论依据。     

小尺寸稀疏镜场能流密度分布模拟研究

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。     

我国太阳能热发电技术的一座里程碑

走进南京江宁经济技术开发区,在道路两旁一排排低矮的厂房中赫然矗立着一座高塔,分外引人注目,它就是我国第一座70kW塔式太阳能热发电示范工程中的关键部分之——接收塔；定日镜群把阳光聚焦在塔顶接收器上,接收器仿佛是一颗“人造     

浅析一种用于塔式太阳能热发电站的定日镜全自动清洗车

在塔式太阳能热发电站中,定日镜的表面清洁度与其聚光集热效率直接相关,合理的清洗策略和高效的清洗设备有助于提升定日镜镜场的平均清洁度,提高其聚光集热效率,进而提升整个太阳能热发电站的发电效率。介绍了一种定日镜全自动清洗车,其基于导航系统和镜场整体控制来完成定日镜镜场的自动清洗工作。     

THE MONTHLY-AVERAGED AND YEARLY-AVERAGED COSINE EFFECT FACTOR OF A HELIOSTAT FIELD

Analyses are given to determine the monthly-averaged and yearly-averaged daily cosine effect factor for a heliostat field. The analyses showed that this factor depends on the latitude angle of the site, the month, and the relative position of the heliostat with respect to the tower. The position of the heliostat is defined in terms of its distance from the tower as multiples of the tower height and a position angle measured from the south direction. Calculations are carried out to determine the dependence of the monthly-averaged and the yearly-averaged daily cosine effect factor on the pertinent parameters. The results are plotted on charts for each month, and for the full year. These results cover latitude angles between 0 and 45^°N, for fields with radii up to 50 tower height. In addition, the results are expressed in mathematical correlations to facilitate using them in computer applications. A procedure is outlined to use the present results to preliminary layout the heliostat field, and to predict the rated MW_th reflected by the heliostat field during a period of a month, several months, or a year.     

Design optimization of a solar tower power plant heliostat field by considering different heliostat shapes

The present study focuses on the optimization of solar tower power plant heliostat field by considering different heliostat shapes including rectangular, square, pentagon, hexagon, heptagon, octagon, and circular heliostat shapes. The optimization is carried out using an in-house developed code-based MATLAB program. The developed in-house code is validated first on a well-known PS10 Solar Thermal Power plant having rectangular heliostats shape and the resulting yearly unweighted heliostat field efficiency of about 64.43% could be obtained. The optimized PS10 heliostat field using different heliostat shapes showed that the circular and octagon heliostat shapes provide better efficiency with minimum land area. The yearly efficiency is increased from 69.65% for the rectangular heliostat shape to 70.96% and 71% for the octagon and circular shapes, respectively. In addition, the calculated field area (land area) is reduced for the case of circular and octagon heliostat shapes with a gain of about 11.10% and 10.93% (about 42.0436 × 10³ and 41.4036 × 10³ m²), respectively, in comparison with the PS10 field area.     

基于自适应引力搜索算法的定日镜场优化布置

针对塔式太阳能热发电电站中定日镜场优化布置问题,提出一种基于自适应引力搜索算法的定日镜场优化布置方法。以Campo布置规则为基础建立比目标定日镜场大1.5倍的密集型初始镜场,将定日镜所在环的半径作为输入变量并将年均效率作为镜场优化布置的评价标准。通过在引力搜索算法中引入动态调整因子α,可提高算法在高维搜索问题方面的求解能力。最后以塞维利亚Gemasolar电站的定日镜场为例进行优化布置,证明使用自适应引力搜索算法优化后的定日镜场具有更高的年均效率。     

A new code for the design and analysis of the heliostat field layout for power tower system

A new code for the design and analysis of the heliostat field layout for power tower system is developed. In the new code, a new method for the heliostat field layout is proposed based on the edge ray principle of nonimaging optics. The heliostat field boundary is constrained by the tower height, the receiver tilt angle and size and the heliostat efficiency factor which is the product of the annual cosine efficiency and the annual atmospheric transmission efficiency. With the new method, the heliostat can be placed with a higher efficiency and a faster response speed of the design and optimization can be obtained. A new module for the analysis of the aspherical heliostat is created in the new code. A new toroidal heliostat field is designed and analyzed by using the new code. Compared with the spherical heliostat, the solar image radius of the field is reduced by about 30% by using the toroidal heliostat if the mirror shape and the tracking are ideal. In addition, to maximize the utilization of land, suitable crops can be considered to be planted under heliostats. To evaluate the feasibility of the crop growth, a method for calculating the annual distribution of sunshine duration on the land surface is developed as well.     

Optimized working temperatures of a solar central receiver

Recent developments in solar tower technology, aimed at the achievement of high temperatures (above 1100 K) for the operation of advanced power conversion units (gas turbine and combined cycle), require careful analysis of their optimal operating parameters. This study presents a method of optimization for design parameters, such as the receiver working temperature and the heliostat field density. This method aims at maximizing the overall efficiency of the three major subsystems that constitute the entire plant, namely, the heliostat field and the tower, the receiver and its accompanying secondary optics, and the power block. The results of this optimization process are shown and analyzed. The principal result demonstrates that the operating temperature has an optimal value and its further increase can lower the overall efficiency of the system.     

An optimization tool to design the field of a solar power tower plant allowing heliostats of different sizes

The design of a solar power tower plant involves the optimization of the heliostat field layout. Fields are usually designed to have all heliostats of identical size. Although the use of a single heliostat size has been questioned in the literature, there are no tools to design fields with heliostats of several sizes at the same time. In this paper, the problem of optimizing the heliostat field layout of a system with heliostats of different sizes is addressed. We present an optimization tool to design solar plants allowing two heliostat sizes. The methodology is illustrated with a particular example considering different heliostat costs. Copyright © 2017 John Wiley & Sons, Ltd.     

A new method for the design of the heliostat field layout for solar tower power plant

A new method for the design of the heliostat field layout for solar tower power plant is proposed. In the new method, the heliostat boundary is constrained by the receiver geometrical aperture and the efficiency factor which is the product of the annual cosine efficiency and the annual atmospheric transmission efficiency of heliostat. With the new method, the annual interception efficiency does not need to be calculated when places the heliostats, therefore the total time of design and optimization is saved significantly. Based on the new method, a new code for heliostat field layout design (HFLD) has been developed and a new heliostat field layout for the PS10 plant at the PS10 location has been designed by using the new code. Compared with current PS10 layout, the new designed heliostats have the same optical efficiency but with a faster response speed. In addition, to evaluate the feasibility of crops growth on the field land under heliostats, a new calculation method for the annual sunshine duration on the land surface is proposed as well.     

水平轴风力机筒型塔架动态响应分析

为获得水平轴风力机塔架在时变载荷作用下的动态响应,将塔架简化成悬臂梁,利用二结点梁单元进行离散化建模,分析了塔架弯曲振动固有动力特性。在建立塔架结构动力学运动方程、计算塔架所受时变载荷的基础上,运用线性加速度法和模态叠加原理对风力机塔架的动态响应进行计算,编制了相应的计算机程序。以某1.0MW风力机塔架为例,获得了风力机在湍流风运行条件下塔架在仿真时间内的位移、速度和加速度,并与"GHBladed"软件的计算结果进行了比较,表明计算模型是可行的。