基于定热源的两种有机朗肯循环系统的经济性分析

Economic analysis of two types of Organic Rankine Cycle systems based on heat source condition constraints

为了分析热源条件约束下两种有机朗肯循环系统的热力性能和经济性的差异,文章根据热力学理论,选取3种工质分别建立无内回热式有机朗肯循环系统和内回热式有机朗肯循环系统的热力模型和经济性模型。通过计算比较了两种系统的热力性能和经济性,并分析了排烟温度对系统经济性的影响。分析结果表明:当采用相同工质的两种系统的净功率相等时,所对应的排烟温度为等效排烟温度;当排烟温度高于等效排烟温度时,IORC系统的净功率高于ORC系统;当工质相同时,IORC系统的投资成本高于ORC系统,IORC系统的净功率高于ORC系统,且二者的差值较小,导致IORC系统的电力生产成本较高,经济性较低;排烟温度不受约束时,采用R123的ORC系统经济性最佳;当排烟温度不高于75℃时,采用R245fa的ORC系统经济性最佳。

In order to analyze the thermal characteristics and economic differences of the two types of Organic Rankine Cycle(ORC)systems under the constraints of heat source conditions.Based on thermodynamic theory,the thermal model of the ORC system without internal heat exchanger and the ORC system with internal heat exchanger(IORC)is established by using three working fluids,and established a system economic model,through the analysis of the thermal performance and economy of the two types of systems,the constraint relationship between the exhaust gas temperature and the economics of the two types of systems is discussed.The results show that when the net power of two systems with the same working fluid is equal,the corresponding exhaust gas temperature is the equivalent exhaust gas temperature;The net power of IORC system is higher than that of ORC system only when the exhaust gas temperature is higher than the equivalent exhaust gas temperature;In the two systems with the same working fluid,the investment cost of IORC system is higher than that of ORC system,while the net power of the IORC system is not much higher than that of the ORC system,resulting in higher levelized electricity cost of IORC system and lower economic feasibility than that of ORC system;When the exhaust gas temperature is not constrained,the economic feasibility of the ORC system using R123 is optimal;Exhaust gas temperature is not higher than 75℃,the economic feasibility of the ORC system using R245fa is optimal.