The use of graphite foams for simultaneous collection and storage of concentrated solar energy
The use of graphite foams for simultaneous collection and storage of concentrated solar energy
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DOI：
10.1016/j.carbon.2015.11.071
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发表时间：
2016-04
期刊：
影响因子：
10.9
通讯作者：
Heinrich Badenhorst;N. Fox;Ashraf Mutalib
中科院分区：
文献类型：
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作者：
Heinrich Badenhorst;N. Fox;Ashraf Mutalib
使用低成本的局部沥青材料和可膨胀石墨制备不同组成和密度的石墨泡沫，用于太阳能捕获。泡沫具有高石墨化度，但表现出精细的马赛克纹理。一个小的氧化处理（6%的质量损失）是必要的，以完全打开泡沫孔。随着密度降低，观察到泡沫表面积的大幅降低。尽管如此，由于通过泡沫的循环增加，测量到太阳能捕获效率的增加。通过改变泡沫的几何形状和浓度比，它被证明，接收器的大小可以减少75%，在相同的效率。具有最低密度的泡沫用于测试使用相变材料的同时能量捕获和存储概念的热性能。相变材料的熔化时间减少了46%，而能量存储密度仅减少了18%。此外，还发现泡沫复合材料由于消除了不一致熔化，导致了更理想的相变行为。该复合材料可以在恒定温度下有效地捕获、存储和释放热能，而无需任何额外的要求。
Graphite foams of varying composition and density were prepared using a low cost, local pitch material and expandable graphite for use in solar energy capture. The foams have a high degree of graphitization but exhibit a fine mosaic texture. A small oxidative treatment (6% mass loss) was necessary to fully open the foam pores. As the density is reduced a large decrease in the foam surface area was observed. Despite this, an increase in solar energy capture efficiency was measured due to increased circulation through the foam. By varying foam geometry and the concentration ratio it was demonstrated that the receiver size can be reduced by 75% at the same efficiency. The foam with the lowest density was used to test the thermal performance of a simultaneous energy capture and storage concept using a phase change material. The melting time of the phase change material is reduced by 46% whilst only reducing the energy storage density by 18%. In addition it was found that the foam composite resulted in more ideal phase transition behaviour due to the elimination of incongruent melting. The composite can effectively capture, store and discharge thermal energy, at a constant temperature, without any additional requirements.