热电制冷系统热端相变材料控温过程调控及冷热端耦合传热特性研究

Thermoelectric cooling (TEC) systems are important equipment which can cool down the portable instrument precisely in high-tech field. However, the hot side of the TEC system will generate a large amount of heat during its operation process, leading to a rise in the hot side’s temperature and a significant drop in the coefficient of the system’s performance. Phase change material (PCM) can absorb thermal energy passively with negligible changes in its temperature. Taking advantage of this, the TEC system with its hot side thermally controlled by PCM-based module not only can present stabilized and decreased temperature of the hot side but also ensure small sizes and energy conversation of the system. A further improvement of the thermal management performance of the PCM-based module for the hot side is urgently needed, especially when it comes to the increase of the operation efficiency of the TEC system, development of the TEC technology and realization of stable, high efficient and energy-saving cooling in high-tech field. .This project focuses on TEC system integrated with PCM-based module. An experimental setup is established to study the heat transfer process between the PCM-based module and the system’s hot side when the hot side is exposed to complicated locations of the thermal resistances and different heat fluxes. Multiple thermophysical properties of PCM which may have significant impacts on the thermal management function of the PCM module are determined. A theoretical model describing the heat transfer behaviors of the TEC system is developed. By using this model, the effects of the PCM properties on the operation performance of the TEC system are studied and how these effects perform is analyzed in details. A strategy of optimization of the TEC system’s cooling performance by properly controlling the thermophysical properties of the PCM is derived. The studies conducted in this project will provide theoretical guidance for the design and practical application of the TEC systems.

热电制冷系统是为尖端技术领域提供移动精准制冷的重要设备。然而，热电制冷系统的运行涉及热端的放热升温，制约了其制冷性能。利用相变材料的自发恒温吸热特性，构建热端相变控温型热电制冷系统，不但能稳定和降低热端温度，还能保证系统的结构紧凑和运行节能可靠。如何有效调控热端的相变控温传热过程进一步提升系统性能，对推进热电制冷技术发展，实现尖端技术领域稳定、高效、低能耗制冷具有重要意义。. 本项目针对热端相变控温型热电制冷系统，设计并搭建相变控温模块与热端传热实验装置，研究确定在热端复杂热阻构成及热流条件下对热端控温过程起主导影响的相变材料关键热物性能因素，建立热端相变控温与冷端制冷耦合动态传热理论模型，利用模型研究相变材料的关键热物性能因素对系统制冷性能的影响规律并揭示机理，提出通过合理选择调控相变材料热物性来提升系统运行性能的策略，为热电制冷系统的设计和运行优化提供指导。

本项目以相变材料技术为基础，旨在为热电制冷系统提供稳定、高效、低能耗的热端温度控制方案。为此，本项目制备并筛选出系列具有高相变潜热（150J/g）、低体积变化率（无量纲体积变化率仅为0.0025）、高热稳定性和相变温度符合热电制冷系统热端控温需求的定形相变复合材料（相变温度范围为30~40ºC）。结合实验测试与人工神经网络模型拟合计算，获得材料的各项热物性能的调控规律及材料的最佳制备工艺方法。在相变复合材料的导热性能调控方面，提出通过提高多孔导热强化介质的含量与复合体系的压缩密度可使复合材料体系在径向方向上获得指数型的导热性能提升。基于所获相变复合材料，本项目构建相变控温模块，建立模块的传热数值模型，结合实验与模型计算结果共同揭示材料的热物性对模块传热控温性能的内在影响机制，并基于此提出控温模块的控温效果主要受复合材料体系的导热性能和相变储能容量共同控制。本项目设计并搭建基于相变复合材料的热端相变控温型热电制冷系统，研究材料的热物性参数变化引起的控温模块传热性能改变对热电制冷系统制冷效果产生的传导性影响，并揭示影响机理。在热端相变控温型热电制冷系统的结构设计上，提出需结合热管技术将热电制冷芯片与控温模块相隔离以减小模块散热对冷端产生的影响。在热电制冷系统的运行方案上，提出针对轴向和径向具有导热性能差异的相变复合材料，由其所构建的控温模块采用径向方向作为热电制冷系统热端的主要热传输通道方向可使制冷系统获得较低的冷端温度，采用轴向方向作为传热通道方向可使制冷系统的制冷系数较长时间内维持在较低水平。