基于开-闭耦合式斯特林机构的液化空气储能方法研究

Compared with traditional compressed air energy storage(CAES) system, liquid air energy storage(LAES) system has a broader application. Because of its high energy density, LAES can be used in the large-scale storage of renewable energy..Liquid air has a 200 centigrade temperature difference with ambient atmosphere, and it can be used to achieve the storing and releasing energy via the conversion between electrical power and cryogenic energy. During the operating process of traditional LAES system, energy circulates by means of ‘electrical –cryogenic –expansive –electrical’. While generating electrical energy, liquid air converts its cryogenic energy into expansive energy by pumping, and continues to convert to electrical energy via expander. The bottleneck of the technique lies in the low conversion efficiency between cryogenic energy and expansive energy. Researchers used to improve efficiency by increasing the working pressure, which requires high in sealing. It also results in very complex structure and a large budget. .In this project, an ‘electrical –cryogenic –electrical’ energy storage method is proposed. Stirling engine is introduced to take place of expander, taking solution of the low efficiency of ‘heat-expansive energy’ conversion by leading in direct conversion from cryogenic energy into electrical energy. During the period of gasification, part of cryogenic can spontaneously convert into expansive energy. Based on the method above, an open-closed coupled Stirling heat-power conversion mechanism is proposed, achieving the coupled conversion from cryogenic energy and pressure energy to electrical energy. The proposed novel can not only improve energy storage efficiency and reduce working pressure, but also simplify structure and cut the costs, therefore improving the promotion of LAES technique.

液化空气储能相比传统压缩空气储能以其储能密度高的优点，适用于可再生能源的大规模储存，具有广阔的应用前景。.液化空气与大气环境存在温差（200℃）而具备冷能，液化空气储能是通过电能与冷能的相互转换实现蓄电和发电。传统基于“电能-冷能-压力能-电能”的储能流程，发电时液化空气经泵的加压，冷能转换为压力能，经膨胀机压力能转换为电能，其瓶颈在于“冷能-压力能”环节压力能转换率低，传统通过增加工作压力来提高效率，对系统的耐压和密封要求高、系统复杂、成本高。.本项目提出了“电能-冷能-电能”的储能方法，引入斯特林热机代替膨胀机，实现冷能向电能的直接转换，以避免低效的“冷能-压力能”环节。由于气化时部分冷能自发转换为压力能，提出了开-闭耦合式斯特林热功转换机构，以实现冷能和压力能向电能的耦合转换。从而达到提高储能效率，降低系统工作压力，简化系统结构，降低成本的目的，有助于液化空气储能技术的推广应用。

液化空气储能作为压缩空气储能的一个重要研究方向，将压缩空气液化，可将储能密度提高一个数量级，适用于可再生能源的大规模储存。液化空气与大气环境存在温差（200℃）而具备冷能，通过电能与冷能的相互转换可实现蓄电和发电。适用于太阳能、风电等可再生能源的大规模储存，应用前景广阔。.目前，液化空气储能系统在液化空气气化时不储存释放的冷量，导致储能效率低（<20%），投资回收期长（10年），还不能投入商业应用。本项目提出了开-闭耦合式斯特林热功转换机构，引入了基于多孔材料的回热器结构，实现冷能的蓄存和释放，以实现液化空气中冷能和压力能向电能的耦合转换，从而提高了液化空气系统热功转换效率。.针对多孔材料在流体中产生的扰动，引起的流体传热特性和阻力特性变化的问题，建立了气-液界面固相扰动下的两相流动力学模型，研究了多孔材料扰动下的两相流换热特性和流体阻力模型，测量了温度、压力以及传热系数等传热和阻力特性参数，验证了上述动力学模型应用于模拟多孔材料传热和阻力的正确性。.针对新型热功转换系统动力学特性不明的问题，建立了耦合冷端模型、热端模型以及回热器模型等子模型的系统动力学模型，模拟了不同负载、转速下系统的动力学特性，分析了气体工作压力、工作温度、活塞扫气比、相位超前角、多孔材料质量和回热器等因素对系统效率的影响。.为了开展基于斯特林循环的液化空气储能应用研究，建立了液化空气斯特林热功转换机构及其实验平台。设计和制作了系统的原理验证样机，验证了将上述系统动力学模型应用于分析系统特性的正确性，验证了基于多孔材料的回热器结构对效率的提升作用，为液化空气热功转换系统的设计和效率的优化奠定了基础。为提高储能效率提供了新的思路和可行技术途径。.取得成果：.（1）在重要学术期刊、国际学术会议上发表学术论文10篇，其中SCI 3篇；.（2）申请发明专利6项，其中已授权4项；.（3）获得2017年国家科技进步奖二等奖（个人排名第4）。.（4）培养博士3名，硕士5名。