Paper presents an idea of utilization infinite regular polyhedrons for designing heat exchange devices. The investigated prototype of the heat exchanger was consisted of twenty identical solids. Each of them was composed from eight regular hexagons. CFD simulations, reported in this paper, were used to obtain an influence of the flow domain modification on the intensification of the forced convection heat transfer in the developed device. Computational analyses clearly showed that the experimental testing of the heat exchanger prototype should be realized with include of cuboid turbulence inserts. Heat transfer performance and pressure drop obtained by experimental investigations are presented, too. The average Nusselt number and Fanning friction factor were expressed in terms of the Reynolds number. (c) 2008 Elsevier Ltd. All rights reserved.