Multi-objective optimization of an irreversible Stirling cryogenic refrigerator cycle

Abstract

The main aim of this research article is a parametric demonstration of irreversible Stirling 
cryogenic refrigerator cycles that includes irreversibilities such as external and internal 
irreversibilities. In addition, through this study, finite heat capacities of external reservoirs 
are considered accordingly. To reach the addressed goal of this research, three objective 
functions that include the input power of the Stirling refrigerator, the coefficient of performance 
(COP) and cooling load (R-L) have been involved in optimization process simultaneously. The 
first aforementioned objective function has to minimize; the rest objective functions, on the 
other hand, have to maximize in parallel optimization process. Developed multi objective 
evolutionary approaches (MOEAs) based on NSGA-II algorithm is implemented throughout 
this work. Moreover, cold-side's effectiveness of the heat exchanger, hot-side's effectiveness 
of the heat exchanger, heat source's heat capacitance rate, heat sink's capacitance rate, 
temperature ratio (T-h/T-c), temperature of cold side are assigned as decision variables for 
decision making procedure. To gain a robust decision, different decision making approaches 
that include TOPSIS, LINMAP and fuzzy Bellman-Zadeh are used. Pareto optimal frontier 
was determined precisely and then three final outputs have been gained by means of the 
mentioned decision making approaches. (C) 2014 Elsevier Ltd. All rights reserved.