摘要
针对谷电转化为热能存储在相变材料中难以被提取的问题,建立了相变蓄热谷电利用装置热性能实验平台。遴选出十二水硫酸铝铵作为相变材料,压铸铝电加热板作为热源,管壳式蓄热箱体作为换热结构。实验中关注了蓄放热过程中PCM的温度趋势及影响因素,重点探究了HTF流量、串联盘管数目及HTF流向3类工况对构建的蓄热装置的放热性能的影响。实验结果表明:PCM的温升趋势主要受距离热源的距离、相变材料初温、温差引起的自然对流效应大小等3个因素的影响;放热过程中,采用水流自下而上的顺连方式及减小流量增加串联盘管数都能提升放热性能,7管顺连,2L·min-1子工况的有效释能时间和,较7管顺连,3 L·min~(-1)子工况分别提升97%、39.7%。有效放热效率分别为179.2min、 91.3%
The thermal energy is difficult to extract when the electricity energy is conversed into heat, which limits the application of heat storage by utilizing off-peak power. The research platform of thermal performance of latent heat storage system was built with the aluminum alloy hexahydrate selected as PCM, die-casting aluminum electrical heating plate as the heat source, shell-tube thermal storage box as the heat transfer structure. The experiment focused on the temperature change of PCM and the influencing factors in the process of heat charging and heat discharging. It shows that there are main reasons for the different temperature rise of the PCM in the circumferential and axial direction: the distance of PCM from the electricity heat plate, the initial temperature of PCM and the natural convection effect. The emphasis was put on the heat discharging process, where the effects of three variable operating conditions on the heat release performance of the thermal storage device were discussed. The results show that the heat performance could be enhanced when the condition of heat transfer fluid flowing from the bottom of the pipe was adopted. In addition,reducing the water flow rate and increasing the number of coil could also gain a higher performance.When pumping water from the bottom of every coil to the top side, the effective release time and efficiency of the 2 L-min~(-1) sub-condition are 179.2 min and 91.3% respectively, which are respectively increased by 97% and 39.7% compared with the equipment operating under the flow rate of3 L·min-1.
引文
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