Thermodynamic analysis and multi-objective optimisation of endoreversible Lenoir heat engine cycle based on the thermo-economic performance criterion

A thermodynamic model of a steady-flow endoreversible Lenoir heat engine cycle (a 'three-point' cycle) coupled with constant-temperature heat reservoirs is established in this paper by using finite-time thermodynamic theory. The cycle consists of one isochoric heating branch, one adiabatic expansion branch and one isobaric cooling branch. A mathematical approach based on the finite-time thermodynamic is proposed to obtain thermal efficiency, the output power and the entropy generation rate throughout the Lenoir system. In this study, an irreversible Lenoir engine is analysed thermodynamically in order to optimise its performance. In this regard, the optimal values of the ecological coefficient of performance and dimensionless thermo-economic objective functions of the Lenoir heat engine are determined. Multi-objective evolutionary algorithms based on Non-dominated Sorting Genetic Algorithm II algorithm is applied to the aforementioned system for calculating the optimal values of decision variables. Decision variables considered in this paper include the ratio of fluid temperature (tau = T-H/T-L), the effectiveness of the cold-side heat exchanger, the effectiveness of the hot-side heat exchanger, the temperature of state 1 and relative investment cost parameter of the hot-side heat exchanger. Moreover, Pareto optimal frontier is applied and an ultimate optimal answer is chosen via three competent decision-making approaches comprising Linear Programming Technique for Multidimensional Analysis of Preference, fuzzy Bellman-Zadeh and Technique for Order of Preference by Similarity to Ideal Solution.