ALGORITHMIC EFFICIENCY OF SIMULATED ANNEALING FOR HEAT-EXCHANGER NETWORK DESIGN

Heat exchanger network synthesis by simulated annealing, a new multivariable optimization method based on the mathematical theory of Markov chains, has recently been reported by Dolan et al. (Foundations of Computer-Aided Process Operations, CACHE, Elsevier, New York, 1987; AICHE Jl 35, 725, 1989). Two aspects of the algorithm strongly affect computation time: the evaluation of the change in cost between different randomly generated states and the annealing temperature schedule. This paper describes a new implementation of the simulated annealing algorithm that efficiently treats the first aspect through the use of a linked-list data structure to calculate changes in cost directly, resulting in a speed increase of two orders of magnitude over earlier implementations of the algorithm. The second aspect is addressed through the use of the annealing schedule of Aarts and van Laarhoven (Phillips J. Res. 40, 193, 1985). This new implementation of the algorithm is used to generate a new low-cost solution to the 7SP4 problem.