车用柴油机余热回收有机朗肯循环系统方案热经济性对比分析

Thermo-economic comparative analysis of different organic Rankine cycle system schemes for vehicle diesel engine waste heat recovery

为实现对车用柴油机余热能量的充分回收,针对简单有机朗肯循环系统和双有机朗肯循环系统进行对比分析研究。根据某车用六缸柴油机的台架试验结果,在研究其变工况下余热特性的基础上,建立两种有机朗肯循环系统的热力学模型和经济模型,并对两个系统的热经济性进行了对比分析。结果表明:在柴油机整个工况范围内,双有机朗肯循环系统的净输出功率、功率提升率和有效燃油消耗率改善度均优于简单有机朗肯循环系统,最大值分别为24.38 kW、8.71%和8.01%;双有机朗肯循环系统的单位能量产出成本为0.8089 CNY·(kW·h)^(-1),比简单有机朗肯循环系统低19.26%。

In order to have a full recovery of the waste heat from a vehicle diesel engine, simple organic Rankine cycle （ORC） system and dual-loop organic Rankine cycle （ORC） system are compared and investigated. According to bench test results of a vehicle six-cylinder diesel engine, the thermodynamic models and economic models of both ORC systems are established, and the thermo-economic comparative analysis of both ORC systems are done on the basis of the study on waste heat characteristics under engine various operating conditions. The results show that, under engine entire operating conditions, net power output, augmentation proportion of power output and improvement of brake specific fuel consumption （BSFC） of the dual-loop ORC system are better than the simple ORC system, the maximum value are 24.38 kW, 8.71% and 8.01% separately; Levelized Energy Cost （LEC） of the dual-loop ORC system is 0.8089 CNY＇（kW·h）^-1 and 19.26% lower than the simple ORC system.