Cascaded latent heat storage for parabolic trough solar power plants
Cascaded latent heat storage for parabolic trough solar power plants
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DOI：
10.1016/j.solener.2006.09.008
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发表时间：
2007-06
期刊：
影响因子：
6.7
通讯作者：
H. Michels;R. Pitz‐Paal
中科院分区：
文献类型：
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作者：
H. Michels;R. Pitz‐Paal
当前太阳能热发电系统（SEGS）的复兴揭示了对于温度范围从250°C到500°C的经济热能存储（TES）的仍然存在的需求。抛物槽式发电厂的TES基准是直接两罐储存，因为它被用于巴斯托（美国）附近的SEGS I工厂。随着昂贵的合成导热油的引入，能够将操作温度从以前的300°C提高到400°C，直接存储技术变得不经济。级联潜热存储（CLHS）是一种可能的TES替代方案，其特点是所需的存储材料最少。使用多级相变材料（PCM）应确保存储材料的最佳利用。本文报道了以NaNO_3、KNO_3等碱金属硝酸盐为工质的梯级潜热蓄热的实验和数值模拟结果。在实际操作参数下，对垂直管壳式换热器装置进行了实验。实验结果被用于数值模型来模拟不同的CLHS配置。使用Dymola/Modelica进行模拟。这项工作的结果表明，一方面，该温度范围的CLHS设计比高达100°C的温度范围更复杂。另一方面，现有相变材料导热系数低是充分利用这一有前途的储能技术必须克服的障碍。
The current revival of solar thermal electricity generating systems (SEGS) unveils the still existing need of economic thermal energy storages (TES) for the temperature range from 250°C to 500°C. The TES-benchmark for parabolic trough power plants is the direct two tank storage, as it was used at the SEGS I plant near Barstow (USA). With the introduction of expensive synthetic heat transfer oil, capable to increase the operating temperature from former 300°C up to 400°C, the direct storage technology became uneconomical. Cascaded latent heat storages (CLHS) are one possible TES alternative, which are marked by a minimum of necessary storage material. The use of a cascade of multiple phase change materials (PCM) shall ensure the optimal utilization of the storage material. This paper reports experimental and numerical results from the investigation of cascaded latent heat storages with alkali nitrate salts like NaNO3, KNO3and others more. The experiments were conducted with vertical shell and tube type heat exchanger devices under realistic operation parameters. The experimental results were used for a numerical model to simulate different CLHS configurations. Dymola/Modelica was used to conduct the simulation. The outcome of this work shows on the one hand, that the design of CLHS for this temperature range is more complex than for the temperature range up to 100°C. And on the other hand, the low heat conductivity of available PCM is an obstacle which must be overcome to make full use of this promising storage technology.