Mixed variable optimization of thenumber and composition of heat interceptsin a thermal insulation systemMichael Kokkolaras

In the literature, thermal insulation systems with a xed number of shields used as heat intercepts have been optimized with respect to the temperatures and locations of the shields. The number of shields and the type of insulators that surround them were chosen by parametric studies. This was because such categorical variables, which refer to a particular choice from a list of \categories", could only be treated as xed parameters by the optimization methods employed. Here, we show that advances in optimization algorithms make it possible to optimize directly with respect to mixtures of continuous and categorical decision variables. We report mixed variable results for two models from the engineering literature, and in one case, we obtain a 65% reduction in the objective function over the previously published result. The main purpose of this paper is to show that the mixed variable optimization algorithms can be applied prootably to a broad class of optimization problems in engineering that could not be solved with earlier methods. (2000), Mixed variable optimization of the number and composition of heat intercepts in a thermal insulation system, TR00-21,