以R123和R245fa为循环工质的车用余热回收系统的(火用)分析

针对以R123和R245fa为循环工质的车用有机朗肯循环余热回收系统，结合重型车用柴油机的试验数据针对系统进行焖（火用）分析.分析结果表明对于R123系统，在不同的发动机转速下，系统焖（火用）效率随着蒸发压力和发动机负荷增大逐渐增大，但是增长速率均逐渐减小.对于R245fa系统，在不同的发动机转速下，系统焖（火用）效率随着蒸发压力的增大先增大后减小，随发动机负荷的增大逐渐增大.蒸发器是提升中温有机朗肯循环系统系统焖（火用）效率的关键，合理选择及设计系统蒸发器将能够有效提高系统焖（火用）效率. 

Exergy Analysis of a Vehicle Waste Heat Recovery System with R123 and R245fa as Working Fluids

Using experimental data of the heavy-duty diesel engine, the system exergy analysis was carried out for a vehicle waste heat recovery system which was an organic rankine cycle (ORC) with R123 and R245fa as working fluids. Results show that under different engine speeds, the R123 system exergy efficiency increases with the increase of evaporation pressure and engine load, but the increase rate decreases gradually. Under different engine speeds, the R245fa system exergy efficiency increases first and then decreases with the increase of evaporation pressure, and increases with the increase of engine load. An evaporator is the key point to improving the system exergy efficiency. An appropriate evaporator for the system can improve the system exergy efficiency effectively.