采用蚁群算法的中温余热有机朗肯循环性能参数优化

Parametric Optimization of Organic Rankine Cycle for Middle-Grade Waste Heat Recovery by Ant Colony Algorithm

鉴于当前针对有机朗肯循环(ORC)和工质的研究大都选取特定循环和工质作为研究对象,缺乏对变工况下工质与系统匹配问题的系统研究,使用蚁群优化算法,以基本有机朗肯循环(BORC)、内回热有机朗肯循环(IHORC)为研究对象,计算比较了不同ORC系统在最佳工况下的系统性能,总结了不同临界温度的工质与不同热源工况的相互匹配关系。结果表明:在相同热源温度下,与BORC系统相比,IHORC系统具有较高的火用效率;根据BORC系统性能参数随热源温度的变化规律,总结出了所考查的工质各自对应的原则可用温度区间;当热源温度接近该区间上限值时,系统获取的热量火用增加,净输出功增加,工质的热力学性能得到了充分发挥;采用临界温度较高的工质时,冷凝器可能真空运行引起运行不稳定,系统经济性下降;按照工质可用温度上限与热源温度尽量相近的标准,可确定与不同热源温度区间相匹配的最佳工质。

The investigation was conducted on the matching criterion between working fluids and cycles under variable working conditions for the organic Rankine cycle （ORC）.The ant colony algorithm was applied to examine the performance of the basic ORC （BORC） and the ORC with an internal heat exchanger （IHORC） under the different operating conditions （i.e.,working fluid and heat source temperature）.On the basis of the results calculated,a matching criterion between the working fluids having different critical temperatures and the heat source temperatures was achieved.The results show that the IHORC displays higher exergy efficiency than the BORC.The BORC system has a higher thermal efficiency and output net power when the heat source temperature reaches the upper limit of the region; when a working fluid with high critical temperature is adopted,the condenser runs at negative pressure,reducing the stability and economy of the system.At a given heat source temperature,the working fluid can be selected according to its optimum temperature region.