基于分液冷凝主动调控非共沸工质组份的有机朗肯循环

The mid-low temperature heat driven organic Rankine cycle (ORC) is subjected to fluctuations of heat sink/source, leading to a serious issue of performance degradation. The active composition-tuning for zeotropic mixture is proposed by using liquid-separation condensation in this project, which has benefits of matching with heat transfer characteristics of heat sink/source, reducing irreversibility and improving the cycle performance for entire conditions. The novel cycle is simple and nearly energy-free during composition-tuning. The project contents include (1) investigations on the method of active designing zeotropic mixture, the matching mechanism between mixture and heat sink/source, and the requirement of composition under variable working conditions; (2) analyses on the thermodynamic, economic and reactive features of active composition-tuning unit to obtain its design principle with precise tuning; (3) discoveries on the steady and dynamic performance of the unit and ORC system, and the adaptability of this novel ORC with fluctuations of heat sink/source; (4) multi-objective optimizations of design and operation of the proposed ORC to reveal its design guideline and operating strategy. This proposed project can greatly promote the design and operation of thermodynamic cycle under variable working conditions, and provides theoretical fundamentals for efficiently and economically operating the zeotropic mixture ORC.

针对中低温有机朗肯循环（ORC）受冷热源属性波动影响运行性能严重削弱的难题，提出采用分液冷凝主动调控非共沸工质组份的思路，使其传热特性与冷热源属性匹配，降低不可逆损失，实现系统全周期综合性能的提升。新循环结构简单、组份调控过程近零能耗。研究内容如下：1）研究非共沸工质主动设计方法，揭示非共沸工质属性与冷热源属性匹配机制，获得变工况主动调控组份需求特性；2）开展基于分液冷凝的组份主动调控单元的热力、经济、变工况响应特性分析，获得组份精准调控单元设计原理；3）探索组份调控单元及组份可调ORC系统的稳态、动态热力性能，研究系统对冷热源波动的适应性；4）开展组份可调ORC系统设计-运行多目标协同优化，提出分液冷凝组份调控单元的设计准则和ORC系统运行控制策略。该项目的研究将丰富和发展热力循环变工况设计、运行策略，为非共沸工质ORC系统高效经济运行的技术路线提供理论支持。

本项目针对中低温热能驱动有机朗肯循环（ORC）系统变工况下运行性能恶化、传统手段调控能力不足的挑战，以提升ORC系统全工况综合性能为目标，构建了基于分液冷凝主动调控非共沸工质组份的ORC系统，围绕该系统开展了工质筛选、气液分离单元传热流动特性模拟和实验、系统实验验证及优化等研究；提出了基于计算机辅助分子设计的ORC系统非共沸工质筛选与设计方法，获得了工质组份与冷热源的属性匹配特性，建立了非共沸工质ORC系统全工况组份主动调控机制；开展了R245fa/R152a等混合工质的管内传热流动特性实验研究并提出了修正的传热流动关联式；开展了联箱-小孔组份分离单元流动特性模拟并获得了不同工况不同结构参数下分液冷凝联箱的组份分离特性，设计了基于分液冷凝的组份调控单元并提出了组份调控单元运行策略，实现了在ORC系统运行过程中快速调控至目标组份；搭建了分液冷凝组份调控ORC系统试验台，开展了组份调控单元及组份可调ORC系统的稳动态测试，验证了提出的组份调控单元的调控能力及组份可调ORC系统的热-经济性能优势；提出了基于时间序列聚合及多周期同步优化的ORC系统设计方法，显著提升了ORC系统的全工况性能。.发表期刊论文25篇，其中SCI检索15篇；申请发明专利5件，授权发明专利1件、实用新型专利4件；培养毕业硕士生10名、在读博士生2名、在读硕士生8名；项目负责人受邀做学术会议特邀报告3次；项目组成员参加国内会议14人次、国际会议3人次。