气动嵌管式相变墙体动态传热特性实验与数值模拟研究

Experimental Study on Dynamic Heat Transfer Characteristics of Pneumatic Embedded Phase Change Wall

将建筑围护结构与相变材料相结合被认为是减少建筑运行能耗的有效技术之一.为了解决静态储能墙体无法同时提高释冷、蓄冷速度的缺点,提出一种气动嵌管式的动态相变墙体,通过实验测试以及采用动网格技术建立并验证其数值模型,再将该模型与静态储能墙体在释冷、蓄冷方面的热工性能进行对比分析.计算结果表明,数值模拟与实验结果内表面温度平均相对误差为0.59%,内表面热流密度平均相对误差为3.55%;在释冷方面,气动嵌管式相变墙体较PCM-O墙体相变材料液化时间延长了4.167 h,累计向室内传递热量减少了32%;在蓄冷方面,气动嵌管式相变墙体较PCM-I墙体相变材料固化时间总体提高了65.8%,内表面热流密度下降速率提高了69.9%,可显著提升昼夜相变材料的融化和凝固效率.

Combining the building envelope with phase change materials is considered as one of the effective techniques to reduce the energy consumption of building operation.In order to solve the drawback that static energy storage wall cannot improve the rate of cold release and cold storage at the same time,this paper proposes a pneumatic embedded tube type dynamic phase change wall,and establishes and verifies its numerical model through experimental testing and using dynamic grid technology,and then compares the thermal performance of this model with static energy storage wall in terms of cold release and cold storage.The calculation results show that the average relative error between numerical simulation and experimental results is 1.72%for the inner surface temperature and 0.57%for the inner surface heat flow density;in terms of cold release,the liquefaction time of phase change material of pneumatic embedded tube wall is 81.8%higher and the inner surface heat flow density is 10.3%lower than that of PCM-O wall;in terms of cold storage,the curing time of phase change material of pneumatic embedded tube wall is 10.3%lower than that of PCM-I wall.The wall phase change material curing time is improved by 56.2%overall,and the decrease rate of heat flow density on the inner surface increaseds by 65.8%,which can significantly improve the efficiency of diurnal phase change material melting and solidification.