Effectiveness-NTU Relationships of Parallel-Plate Moving Bed Heat Exchangers

Moving bed heat exchangers (MBHEs) are used in various industrial processes. Recently, analytical solutions to several MBHE heat transfer problems have been presented in the literature. In this work, the mathematical procedure by which these new solutions are used to construct effectiveness-NTU relationships is presented, for parallel-plate configurations. Expressions for both co- and counter-current orientations are outlined. Effectiveness-NTU plots are then generated, and contrasted with those of fluid-fluid systems. As expected, a functionality with respect to the Number-of-Transfer-Units and the Capacity Ratio is observed. A novel dependency with respect to the Biot number is also demonstrated, whereby effectiveness decreases with increasing Biot number, due to the increasing resistance imparted by the diffusion of energy through the solids bulk. These effectiveness-NTU plots can serve as a design platform, which engineers can use to size and rate MBHEs.