Development and Prototype Testing of Low-Cost Lightweight Thin Film Solar Concentrator
Development and Prototype Testing of Low-Cost Lightweight Thin Film Solar Concentrator
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低成本轻质薄膜太阳能聚光器的开发和原型测试
DOI：
10.1115/es2016-59692
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
K. Gidanian
中科院分区：
文献类型：
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作者：
G. Ganapathi;A. Palisoc;A. Buchroithner;S. Nataraj;B. Nesmith;A. Kindler;G. Greschik;K. Gidanian
能源部SunShot计划资助了一项低成本的基于硬质泡沫的浓缩器技术开发计划，以满足75美元/m2的安装成本目标，而目前的成本为200 -250美元/m2。该项目的第一阶段侧重于设计交易和成本分析，从而产生一种成本优化的自供电自主跟踪定日镜概念，其镜面面积在100平方米范围内。在第2阶段中，开始对基于反射率为94%的ReflecTec薄膜粘合在复合泡沫基材上的反射镜模块进行30年加速测试，并在第3阶段完成。15个试样的测试表明，光学性能下降小于5%的镜面反射率以下30年的等效紫外线测试和其他滥用测试，如酸雨，鸟下降，热循环等。一个小规模的原型（3米× 2米）的定日镜设计的基础上，模块化桁架元件与可拆卸的镜子模块详细开发。在此阶段，根据风载荷要求和指向精度要求确定双轴致动器等组件的尺寸和选择。使用三个独立的商业代码- ANSYS、COMSOL和SolidWorks对具有反射镜模块的机械结构进行有限元分析，以验证由高达35 mph的结构上的风载荷引起的光学误差。结果表明，RMS偏转小于0.4 mrad的指向误差。定日镜的动态响应表明，前5个本征模式在17-20 Hz范围内。桁架和C型轨等单个结构元件在当地制造，并在实验室中与镜面组装，以进行初始配合检查和测试。九个镜面面的表面误差的特点是使用摄影测量和验证使用反向哈特曼技术，并显示在1 mrad或更小的顺序。一个三级控制器（主，网关和定日镜）的架构和建设。跟踪太阳是使用NREL的太阳跟踪算法在网关控制器中实现。为每个定日镜计算目标指向矢量，并将其无线传送到各个定日镜控制器，用于致动方位角和仰角电机。由太阳能电池板和电池组成的电源子系统为致动器和控制器板提供24V。该系统的大小可在电源不可用时为5小时的运行提供足够的电力。初始校准将使用现场摄像机进行，该摄像机跟踪位于距定日镜约52米处的目标上的太阳图像。将在平静和有风的条件下对定日镜指向进行测试，以证明其整体性能符合DOE在27英里/小时风速下4 mrad的目标。商业化的努力正在进行中，以过渡到商业部门的设计。该项目正在接近总成本目标，目前的估计约为S90-110/m^2，并且可以通过我们已经确定的膜的替代品来实现更低的成本。
A low-cost rigid foam-based concentrator technology development program was funded by the DOE SunShot Initiative to meet installed cost goals of $75/m^2 vs. current costs of ∼ $200–250/m^2. Phase 1 of the project focused on design trades and cost analyses leading to a cost-optimized self-powered autonomous tracking heliostat concept with a mirror surface area in the 100m^2 range. In Phase 2 30-year accelerated testing of the mirror modules based on ReflecTec film with 94% specular reflectivity bonded on composite foam substrate were initiated and completed in Phase 3. The tests with 15 coupons showed optical performance degradation of less than 5% in specular reflectance following 30-year equivalent UV testing and other abuse testing such as acid rain, bird dropping, thermal cycling, etc. A small scale prototype (3m×2m) heliostat design based on modular truss elements with removable mirror modules was developed in detail. In this phase components such as the dual-axis actuators were sized and selected based on wind load requirements and pointing accuracy demands were completed. Finite Element analyses for the mechanical structure with mirror modules were performed using three separate commercial codes — ANSYS, COMSOL and SolidWorks to validate the optical errors induced by wind loads on the structure up to 35 mph. Results indicated that the RMS deflections contributed to less than 0.4 mrad pointing error. Dynamic response of the heliostat indicated that the first 5 eigenmodes were in the 17–20 Hz range. The individual structure elements such as the trusses and c-rails were fabricated locally and assembled with the mirror facets in the lab for initial fit check and testing. The nine mirror facet surface errors were characterized using photogrammetry and verified using Reverse Hartmann techniques and showed to be in the order of 1 mrad or less. A three-level controller (main, gateway and heliostat) was architected and built. Tracking of the sun is done using NREL’s Sun Tracking Algorithm implemented in the gateway controller. Target-pointing vectors are calculated for each heliostat and conveyed wirelessly to the individual heliostat controllers for actuating the azimuth and elevation motors. The power subsystem consisting of solar panels and a battery provide 24V for the actuators and controller boards. The system was sized to provide adequate power for a period of 5hrs of operation when power is not available. Initial calibration will be performed with on-site camera tracking the sun’s image on a target located approximately 52m from the heliostat. Testing of the heliostat pointing under calm and windy conditions will be done to demonstrate overall performance that meet DOE targets of 4 mrad under 27 mph winds. Commercialization efforts are underway to transition the design to the commercial sector. The project is well on its way to approaching overall cost targets and current estimates are approximately S90–110/m^2 and lower costs can be achieved with alternates to the film we have identified.