Composite reactants of calcium chloride combined with functional carbon materials for chemical heat pumps
Composite reactants of calcium chloride combined with functional carbon materials for chemical heat pumps
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DOI：
10.1016/j.applthermaleng.2006.02.032
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发表时间：
2008-03
影响因子：
6.4
通讯作者：
K. Fujioka;K. Hatanaka;Y. Hirata
中科院分区：
文献类型：
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作者：
K. Fujioka;K. Hatanaka;Y. Hirata
反应器床层的强化传热是气固化学热泵发展的重要课题之一。研究了氯化钙与膨胀石墨（EG）、活性炭纤维（ACF）的复合反应物对甲醇工质与氯化钙反应的促进作用。我们测量的有效热导率以及体积和空隙率在反应周期的变化。EG复合床的有效导热系数大于未处理氯化钙床的60%。由于膨胀石墨的体积结构，EG复合材料的总空隙率大于0.8。当通过压缩床层将总空隙率降低到0.78以下时，有效热导率急剧增加，比未处理的氯化钙床层的有效热导率高10倍。相反，ACF复合床的有效导热系数略小于氯化钙床，压缩对其影响不大。这些复合颗粒床的体积和总空隙率仅随反应的甲醇的量轻微变化，而不含碳材料的氯化钙床的体积和总空隙率受反应的影响很大。
Enhancement of heat transfer in the reactor bed is one of the most important subjects for developing gas–solid chemical heat pumps. This study deals with composite reactants combining calcium chloride with expanded graphite (EG) and activated carbon fiber (ACF) to promote the reaction between calcium chloride and working fluid of methanol. We measured variations of effective thermal conductivity as well as volume and void fraction during reaction cycles. Effective thermal conductivity of the EG composite bed was larger than 60% that of untreated calcium chloride bed. Because of the bulky structure of expanded graphite, the overall void fraction of EG composite was larger than 0.8. When the overall void fraction was reduced below 0.78 by compressing the bed, the effective thermal conductivity was sharply increased up to 10 times higher than that of untreated calcium chloride bed. On the contrary, the effective thermal conductivity of ACF composite bed was slightly smaller than that of calcium chloride bed and no remarkable change was brought about by compression. The volume and the overall void fraction of these composite particle beds varied only slightly with the amount of methanol reacted, while those of calcium chloride bed without carbon materials were largely influenced by reaction.