中文摘要：

应用有机朗肯循环（ORC）进行低温余热的回收,不但注重其热力学性能还要考虑其经济性。本文分别选取R125和R143a作为超临界ORC的工质,采用EES软件,应用四种综合性指标对超临界ORC参数包括膨胀机进口压力、冷凝温度和换热器夹点温差进行了优化。结果表明,在工业锅炉中常见的排烟温度423.15 K的条件下,采用F4作为综合指标进行优化时,获得的循环参数最好,适宜作为超临界ORC的优化指标;以F4作为目标进行优化,超临界ORC膨胀机进口参数和冷凝温度都存在优化值;当蒸发器和冷凝器夹点温差固定其中一个时,另外一个可能存在优化的状况;当蒸发器和冷凝器夹点温差之和固定为某一值时,蒸发器和冷凝器夹点温差存在优化的分配。

英文摘要：

Not only thermodynamic performance but also economic performance should be taken into consideration when organic Rankine cycle（ORC） is applied for the recovery of low temperature exhaust heat.In this paper,a comprehensive performance indicator F4 was proposed based on existing thermodynamic and economic indicators.This indicator could reflect both thermodynamic and economic performance of supercritical ORC and was compared to the single indicator.The parameters of supercritical ORC including the expander inlet pressure,condensation temperature and the pitch point temperature difference of heat exchangers are optimized with four integrated indexes adopting R125 and R143 a as working fluid,respectively.The results show that,under the temperature of 423.15 K which is the common temperature in exhaust gas of industrial boiler,the proposed comprehensive index F4 is suitable for the optimization of supercritical ORC system.When F4 is regarded as the index,there are optimal values for the expander outlet parameters and condensation temperature.When the evaporator pinch point temperature difference is fixed at 10 K,there exist optimal condenser pinch point temperature differences for supercritical ORC.When the coupled pinch point temperature difference is fixed at 10 K,there exist an optimal evaporator pinch point temperature difference for supercritical ORC.That means there exists an optimal distribution of the coupled pinch point temperature difference.