双层定型相变墙体在合肥地区传热特性的数值模拟

Numerical Simulation of Heat Transfer Characteristics of Double-layer Shaped Phase Change Wall in Hefei

为探究双层相变墙体所使用的相变材料在不同季节下的相变表现,以合肥地区夏、冬两季室外温度数据为背景,基于Fluent焓-孔隙率法,对普通墙体和双层相变墙体的传热过程进行仿真计算。结果表明,在夏季工况下,外相变板的相变温度为36℃的相变墙体综合表现更好,墙体内表面热流密度与普通墙体相比降低了20.53%,平均延迟时间约为普通墙体的1.8倍。在冬季工况下,内相变板的相变温度为14℃的相变墙体内表面温度波幅较平缓,墙体内表面热流密度与普通墙体相比降低了16.25%,它的衰减倍数约为普通墙体的1.2倍。在合肥地区,使用相变温度为36℃的外相变层和相变温度为14℃的内相变层的墙体在制冷、采暖期单位面积可降低热/冷负荷分别为1.86 W、3.75 W,该种墙体具有很好的节能效果和经济效益。

In order to explore the performance of phase change materials used in double-layer phase change wall in different seasons,based on the outdoor temperature data of Hefei in summer and winter,the heat transfer processes of the ordinary wall and double-layer phase change wall were simulated with Fluent enthalpy-porosity method.The results showed that in summer,the phase change wall with the external phase change plate at 36℃ had the greatest comprehensive performance.Compared to the ordinary wall,the heat flux on the internal surface of the wall was reduced by 20.53%and the average delay time was about 1.8 times.In winter,the temperature fluctuation of the internal surface of the phase change wall with the internal phase change plate at 14℃ was smooth.Compared to the ordinary wall,the heat flux of the internal surface of the wall was reduced by 16.25%and its attenuation multiple was about 1.2 times.In Hefei,the wall using the external phase change layer with a phase change temperature of 36℃ and the internal phase change layer with a phase change temperature of 14℃ can reduce the heat/cooling load of 1.86 W and 3.75 W per unit area,respectively,in the cooling/heating periods,which is energy-saving and economic.