Parametric optimization and performance analysis of ORC (organic Rankine cycle) for diesel engine waste heat recovery with a fin-and-tube evaporator

• Published in: Energy (Oxford) 2015-11, Vol.91, p.128-141
• Main Authors: Yang, Fubin, Zhang, Hongguang, Bei, Chen, Song, Songsong, Wang, Enhua
• Format: Article
• Language: English
• Subjects: Condensation; Diesel engine; Diesel engines; Engines; Evaporation; Heat recovery; Heat transfer; Optimization; Organic Rankine cycle; Parametric optimization; Rankine cycle; Thermodynamic analysis; Waste heat recovery
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2015.08.034

This paper presents the parametric optimization and performance analysis of ORC (organic Rankine cycle) system using GA (genetic algorithm) for recovering exhaust waste heat of a diesel engine. First, the effects of three key parameters, including evaporation pressure, superheat degree and condensation temperature on the system performances are conducted with POPA (net power output per unit heat transfer area) and EDR (exergy destruction rate) as objective functions. The optimal evaporation pressure, superheat degree and condensation temperature corresponding to the maximum POPA and the minimum EDR are provided under engine various operating conditions. Subsequently, as a key component of the ORC system, the performance of a fin-and-tube evaporator used in this ORC system is evaluated. The results show that the optimal evaporation pressures are mainly influenced by the engine operating conditions, whereas the superheat degree and the condensation temperature present a slight variation over the whole operating range. Furthermore, the PPTD (pinch point temperature difference) in the evaporator may occur at different positions with the variation of engine operating conditions. At engine maximum rated power point, the ORC system can achieve maximum POPA of 0.74 kW/m2, and the ratio of maximum effective heat transfer area to actual area of the evaporator is 69.19%. •Parametric optimization and performance analysis of an ORC for diesel engine waste heat recovery are conducted.•The GA (genetic algorithm) is adopted for multi-objective optimization of ORC system.•The effects of main operating parameters on the performance of ORC system are analyzed.•The optimal operating parameters of ORC system over the whole operating range of diesel engine are identified.•The performance of a fin-and-tube evaporator used in ORC system is examined.