Numerical studies by the Galerkin finite element method are presented for the suppression of natural convection heat transfer in a horizontal porous annulus heated from the inner surface. Azimuthal partitions are employed to reduce heat transfer, and the effects of the number of partitions and their positions are examined. For a single partition, its position has a negligible effect on heat transfer in the boundary layer regime. An increase in the number of partitions is effective in suppressing natural convection, and it is found that the Nusselt number Is inversely proportional to (N + 1), where N is the number of partitions.