Multi-objective optimization of fin-and-tube evaporator for a diesel engine-organic Rankine cycle (ORC) combined system using particle swarm optimization algorithm

• Published in: Energy conversion and management 2017-11, Vol.151, p.147-157
• Main Authors: Liu, Hongda, Zhang, Hongguang, Yang, Fubin, Hou, Xiaochen, Yu, Fei, Song, Songsong
• Format: Article
• Language: English
• Subjects: Algorithms; Design; Design optimization; Diesel; Diesel engine; Diesel engines; Evaporation; Fin-and-tube evaporator; Heat recovery; Heat recovery systems; Multiple objective analysis; Objective function; Optimization algorithms; Organic Rankine cycle; Particle swarm optimization; Pressure; Pressure drop; Rankine cycle engines; Waste heat recovery
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2017.08.081

•A mathematic model with phase change of fin-and-tube evaporator is established.•The effect of key geometrical parameters on optimization objectives is analyzed.•PSO algorithm is employed for optimization based on the fin-and-tube evaporator.•Optimal design of the evaporator is achieved for the specific operating condition. In this paper, a mathematical model of fin-and-tube evaporator of ORC system used for waste heat recovery of a diesel engine is established. Particle swarm optimization (PSO) algorithm is applied for the multi-objective optimization of the fin-and-tube evaporator. Key geometrical parameters such as the inlet radius of the tube side, the inlet radius of the shell side, fin height, fin thickness and fin spacing are selected as decision variables. Total annual cost, volume of tube bundle, and exhaust pressure drop are considered as optimization objectives (objective functions). The linear weighted method is used to assign a weight coefficient to each objective function. Calculation results obtained by MATLAB R2010a clearly show a contradictory relationship among the objective functions. For a specific operating condition of the diesel engine, multi-objective optimization of the fin-and-tube evaporator is performed, and the optimal design is obtained. Compared with the results of the original design, the multi-objective optimization results are more satisfactory, the volume of tube bundle is increased by 6.49%, meanwhile the total annual cost is decreased by 71.46% and exhaust pressure drop is reduced by 27.6%. The PSO algorithm based fin-and-tube evaporator design method is beneficial to improving the performance of the diesel engine-organic Rankine cycle (ORC) combined system.