A 2D numerical analysis of rectangular duct with packed bed is carried out for modified Reynolds number (Re_m) ranging from 630 to 14400 with steel balls of diameter (D_p) 5, 9 and 13 mm and bed porosity (ε) of 0.2, 0.5 and 0.8 under local thermal non equilibrium (LTNE) and local thermal equilibrium (LTE) conditions by using COMSOL 6.0 multiphysics CFD software. Effect of varying the Re_m on convective heat transfer coefficient (CHTC) and pressure drop for different ball diameters and bed porosity is studied with water as heat transfer fluid (HTF) under steady state and then the results are compared with finned and empty duct. CHTC is substantially increased in packed bed duct and it is almost 4 times and 11 times more than that of finned and empty duct respectively at the cost of pressure drop. Size of packing material and bed porosity controls the CHTC in packed bed. It increases with decrease in ball diameter and bed porosity. Packing material conductivity has greater influence on CHTC in packed bed. Overall, the performance of packed bed duct is much improved as compared with empty and finned structures for the given geometry specifications with respect to operation, maintainance and cost point of view. Packed bed option has a potential to replace the costlier finned structures and can be successfully used for heat exchange devices.