According to manufacturing considerations, adding complexity in design may not be favorable for practical purposes. The central objective of this paper is to propose a simple type of cavities, consisting of N branches of equal cavities intruding into the symmetrical and equal divisions of a rectangular/trapezoidal heat generating body. To accomplish this, we perform an optimization process to seek for the optimal "N-branch" cavities, which minimize the peak temperature of the body with respect to the constraint of fixed volume occupied by all cavities. We show that, by utilizing the so-called cavities, which are not of a complex type at all, the heat generating body operates at the lower level of the peak temperature when compared with those cavities of complex type found in literature. Realizing that the manufacturing processes and the mathematical intricacies of the optimization process of complex cavities pose a burden, we conclude that the utilization of cavities of complex type, such as T, Y, T-Y or H-shaped cavities must be avoided. In sum, we recommend that for practical engineering applications, the so-called complex cavities must be replaced by cavities of simpler type, such as the N-branch shaped cavity, which is studied in the present work. (C) 2012 Elsevier Ltd. All rights reserved.