【摘要】 针对相变蓄热材料实际应用中的周期性释热情况,本文采用响应面法设计实验方案,对一种基于圆环形赤藻糖醇/膨胀石墨复合相变材料的间接式蓄热器进行周期性释热实验。利用蓄热材料的释热量、释热动力、有效能利用率对蓄热单元的释热性能进行分析。结果表明:当间歇时间为20 min,材料累计释热时间为40 min,总释热功率、斯蒂芬数、火用效率均随着运行时间的增加存在极值,其中火用效率极值出现时间相对于总释热功率和斯蒂芬数要滞后22%,综合考量3个评价指标得出运行时间7.7min为最佳结果。更多还原

【Abstract】 For the problem of periodic heat release in the practical application of phase-change thermal storage materials,a response surface method was used to design an experimental program on an indirect heat accumulator,based on a circular erythritol/expanded graphite composite phase-change material.The performance evaluation of the thermal storage unit was carried out through the total heat release,potential heat,and effective energy utilization of the thermal storage material.The results showed that when the intermittent time was 20 min and the cumulative heat release time of the material was 40 min,with the increase in running time,the total heat release,Stephen number,and exergy efficiency had extremum values.In addition,the appearance time of the extremum of the exergy efficiency was 22% lagged behind those of the total heat release and Stephen number.It was concluded that the running time of 7.7 min is the best value that simultaneously satisfies the optimization of the three evaluation indicators.更多还原