Many-objective optimization of cross-flow plate-fin heat exchanger

This paper presents a rigorous investigation of many-objective (four-objective) optimization of cross flow plate-fin heat exchanger and its comparison with multi-objective (two-objective) optimization. Maximization of effectiveness and minimization of total annual cost, total weight and number of entropy generation units are considered simultaneously as objective functions during many-objective optimization. Multi-objective heat transfer search (MOHTS) algorithm is introduced and applied to obtain a set of Pareto-optimal points of many-objective problem. Application example of plate-fin heat exchanger is presented to demonstrate the effectiveness and accuracy of proposed algorithm. Many objective optimization results form a set of solutions in four dimensional hyper objective space and for visualization it is represented on a two dimension objective space. Thus, results of four-objective optimization are represented by six Pareto fronts in two dimension objective space. These six Pareto fronts are compared with their corresponding two-objective Pareto fronts. Different decision making approaches such as LINMAP, TOPSIS and fuzzy are used to select the final optimal solution from Pareto optimal set of the many-objective optimization. Finally, to reveal the level of conflict between these objectives, distribution of each design variables in their allowable range is also shown in two dimensional objective spaces.