高效梯级相变蓄冷填充床的传热流动耦合机理及其在空调蓄冷过程中的动态特性研究

The phase change cold storage packed bed has been got wide attention in the research on cold storage technologies in air-conditioning systems. According to the performance optimization of a phase change cold storage packed bed and the improvement of energy efficiency of air-conditioning in the process of cold storage, the red blood cell bionic structure is supposed to be used to effectively improve the heat transfer efficiency of a phase change cold storage package and optimize the flow characteristics of heat transfer fluid inside a phase change cold storage packed bed. And then, the cascade cold storage mode is utilized to build a phase change cold storage packed bed to further enhance the heat transfer efficiency and exergy efficiency of a cold storage system. Therefore, both theoretical and experimental methods will be used in this project to deeply study the coupling mechanism of heat transfer and flow of an efficient cascade cold storage packed bed as well as its dynamic characteristics in the process of cold storage in an air-conditioning system. The research contents mainly include: a) red blood cell shape phase change cold storage package and its dynamic heat transfer characteristics in the process of cold charging and discharging; b) the coupling mechanism of heat transfer and flow as well as cold storage performance of a cascade cold storage packed bed based upon red blood cell shape phase change cold storage packages; c) the matching design of a cascade phase change cold storage packed bed as well as its dynamic characteristics and control characteristics during cold storage of an air-conditioning system. As a result, the theoretical foundation will be supplied for the purpose of the efficient construction of a phase change cold storage packed bed and its reasonable application in an air-conditioning system. Besides, such a novel idea will be exploited by way of the profound development and efficient utilization of cold storage technologies in air-conditioning systems.

相变蓄冷填充床在空调蓄冷技术的研究中得到广泛关注。针对相变蓄冷填充床的性能优化问题及其在蓄冷过程中空调能效的提升问题，本项目设想利用红细胞形仿生结构有效提高相变蓄冷封装体的传热效率，并优化相变蓄冷填充床内部传热流体的流动特性；在此基础上采用梯级蓄冷模式构建相变蓄冷填充床进一步提升蓄冷系统的传热效率和火用效率。为此，本项目将从理论和实验两方面对高效梯级相变蓄冷填充床的传热流动耦合机理及其在空调蓄冷过程中的动态特性进行深入研究，内容主要包括：红细胞形相变蓄冷封装体及其蓄冷/释冷过程的动态传热特性；基于红细胞形相变蓄冷封装体的梯级相变蓄冷填充床传热流动耦合机理及蓄冷性能；梯级相变蓄冷填充床匹配设计及其在空调蓄冷过程中的动态特性和控制特性。为相变蓄冷填充床的高效构建及其在空调系统中的科学应用提供理论依据，也为空调蓄冷技术的深入发展和高效利用开辟新的思路。

相变蓄冷填充床具有蓄冷密度高、蓄冷过程温度恒定等优点，在空调蓄冷技术的研究中得到广泛关注。但传统相变蓄冷填充床普遍采用球形的相变蓄冷封装单元，该结构比表面积小，不利于内部相变传热。其次，传统单级相变蓄冷器在蓄冷品位及能效上也有进一步提升的空间。针对以上问题，本课题提出相变材料的红细胞(RBC)形封装形式，构建了梯级相变蓄冷填充床，并对填充床的传热流动耦合机理及其在空调蓄冷过程中的动态特性进行了研究。研究内容主要包括：红细胞形相变蓄冷封装体及其蓄冷过程的动态传热特性研究；红细胞封装单体堆积模式及其对填充床传热流动耦合特性与蓄冷性能的影响；梯级相变蓄冷填充床的匹配设计及其在空调蓄冷过程中的动态特性。实验及数值模拟结果表明，RBC形相变材料封装体传热性能相比球形封装体提升约68%；基于RBC形封装体的相变蓄冷填充床蓄冷速率相比于球形封装体填充床提升了40%以上；梯级相变蓄冷填充床㶲效率比单级蓄冷填充床提升了5%以上，传热性能提升11%-35%。本课题基于仿生学原理，创新性地提出红细胞形相变蓄冷封装体结构，揭示了相变蓄冷填充床的流动传热耦合机理，显著提升相变蓄冷填充床的传热特性及蓄冷性能，为相变蓄冷填充床的高效构建及其在空调系统中的科学应用提供理论依据。