Porous media becomes a potential alternative for cooling technology since it has large contact surface area that strongly enhance heat transfer and exchanging energy within pore channel. A computational fluid dynamics of conjugate heat transfer and periodic boundary condition were applied in FLUENT 6.3.26. Simulations of fixed bed spheres as porous media inside pipe flow were carried out in the range of Reynolds number 5000 to 80000. Simulation methodology was validated by analytical prediction. In the range of Reynolds number 100 - 6000 is very good agreement, however in the range of Reynolds number above 6000 - 10000 just fairly agree. This is caused by the fact that in the range of Reynolds number above 6000 analytical model does not use turbulence model. Fluctuation effects are just considered as dispersion. The results shows that the fixed bed spheres for porous structure gives the highest value of the cooling effectiveness than the other porous structures except for ReD ≤ 10000, the cooling effectiveness of the discrete porous structure is higher compared to the analyzed fixed bed porous structures. At ReD = 15,000 the fixed bed spheres gives 28%, 65% and 160% higher effectiveness compared to the discrete porous structure, 60° broken ribs and 90° continuous ribs, respectively.