优化型复合定形相变材料的传热研究及在储能墙体中的应用

The latent heat energy storage technology will be one of the most effective techniques for solving the problem, which can resolve the conflict of matching energy in time and space and improve energy efficiency. In this research project, the structure and performance of the composite phase change materials could be optimized. And the super efficient innovative latent heat material will be developed. Meanwhile, the project will focus on the research of shape-stabilized phase change material, and the conventional effective thermal conductivity prediction model will be improved, and a new fractal-cavity thermal conductivity model is established by the fractal theory, which the volume change in phase transformation of phase change materials and the cavity caused by manufacturing technology is also considered. On this basis, according to the microstructure in the phase change material and its thermo physical property change, the solid/liquid phase change heat transfer process with complicated nonlinearity is solved numerically by using apparent heat capacity method and its applied research in phase change wall is researched, which reveals the mechanism how to influence thermal storage capacity and rate of latent heat materials from theory and experiment. The research of the project will achieve the technology breakthrough in super efficient innovative composite shape-stabilized phase change technology and capsulation technology, and also solve the technical bottleneck that thermal storage capacity and rate is poor. Furthermore, it will promote the extensive application of the phase change material in the building field.

采用潜热储能技术是缓解能量供求在时间和空间上不匹配的矛盾，且提高能源利用率的有效且亟待研究的途径之一。本项目尝试对复合相变材料的结构及性能进行优化，开发出高导热定形相变胶囊的革新型潜热储能材料，同时开展以该定形相变材料为研究对象，对传统的复合材料导热系数预测模型进行改进，考虑相变材料相态转变时的体积与空腔的变化，提出新型的分形-空腔理论模型，并在此基础上结合相变材料内部真实的微观结构及相变材料相变时的热物性变化，采用显热容法对其非线性特征复杂的固液相变传热过程及其在储能墙体中的应用进行探讨和研究，从理论与试验多角度揭示影响潜热蓄热材料的储存量和储存速率的作用机制。本项目的研究将实现定形相变复合高效储能关键技术和胶囊化封装关键技术的突破，解决潜热蓄热材料的储热容量与储存速率较低的技术瓶颈，促进了相变储能材料在建筑领域的广泛应用。

建筑节能是涉及人类生存环境的大课题，而潜热储能技术是解决该能源问题的重要技术手段之一，可化解能量供求在时间和空间上不匹配的矛盾，是提高能源利用率的有效方法。本课题开发出毫米级高导热定形相变胶囊的新型潜热储能材料，开展以该相变胶囊为对象的相变传热的数值研究及其在建筑墙体中的应用探讨，并辅以必要的理论分析与试验研究。结果表明加入膨胀石墨之后，定形相变胶囊内的载体基质形成了更加精细的微观结构，石蜡分布更均匀。添加了4%的高导热材料膨胀石墨之后，定形相变胶囊的导热系数提高了2倍之多，并有效提高其相界面移动速率和瞬时热流释放量。该研究解决了超高效革新性潜热蓄热的关键技术和储热容量与储存速率较低的技术瓶颈，促进了相变储能材料在多个领域特别是建筑领域的广泛应用。