Performance Optimization Of Organic Rankine Cycle System Based On Particle Swarm Optimization And Aspen Plus Software

With the increasing of automobile ownership, large amount of petroleum resources are consumed which cause serious environmental pollution. Therefore, recovering the waste heat from vehicle internal combustion engine is an effective method for the improvement of thermal efficiency, saving fuel and reducing pollutant emission. The waste heat of internal combustion engine is released into the air mainly in the form of exhaust gas and coolant, which temperature is low and difficult to recovery. The organic Rankine cycle(ORC) system has unique advantage of recovering the low temperature waste heat, so recovering the waste heat of vehicle internal combustion engine has been widely studied by scholars.The operating performances of key part of ORC system were analyzed using Aspen Plus software under the rated condition of a vehicle diesel engine. Subsequently, the models of simple ORC system, ORC system with IHE and regenerative organic Rankine cycle(RORC) system have been built under the analyzed of the key part of ORC system. The operation performances of three ORC systems under diffirent operating parameters had been studied by sensitivity analysis. Based on the analysis results, the operating performances of three vehicle engine-ORC systems also had been analyzed. The results show that, the net power output of the simple ORC system, ORC system with IHE and RORC system can reach up to 21.20 k W, 27.60 k W and 21.75 k W, respectively. And the operation performance of ORC system with IHE is the best compared with operation performance of simple ORC system and RORC system.The variation tendency of exhaust energy rate under various operating conditions of the diesel engine was analyzed by means of experimental data. A RORC system was employed to recover the exhaust energy of the diesel engine. Operating performances of the RORC were analyzed for different working fluids under various operating conditions of the diesel engine using the particle swarm optimization. The results showed that, working fluid butane has the best thermodynamic performance among the nine selected working fluids, but it has high flammability. Therefore, the pure working fluid R124 and mixture working fluid R416 A are the best choice among the nine selected working fluids for the RORC system, considering the operating performance, safety performance and environmental protection property.Based on the variation tendency of exhaust energy rate under various operating conditons of the diesel engine, the particle swarm optimization was adopted for multi-objective and multi-parameter optimization of simple ORC system, ORC system with IHE and RORC system. The results showed that, the optimal operating parameters of the ORC system are different with the various diesel engine operating conditons and the ORC system configuration. What's more, the operation performance of ORC system with IHE is the best compared with operation performance of simple ORC system and RORC system.