Aluminum Open cell heat exchanger with cell diameter 10mm were manufactured having base area measuring 100mm 45mm.It is attached to the copper Plate which is heated by a cylindrical heater inserted in copper plate. Other sides of Copper base plate are insulated so that heat flow is unidirectional and pass through the cellular structure. Results of Natural Convective heat transfer in Aluminum open cell heat exchanger heated from below are presented. Samples of Regular Aluminum Open cell cellular structure with porosity ( ) having different height are used to study the effects of Geometry on heat transfer to air. Results indicate that with Aluminum open cell cellular structure attached to the copper plate the temperature of base copper plate has been considerably reduced for different heat flux in comparison with the base case when there is only copper plate heat from below with different heat flux. So the open cell cellular structure can dissipate higher amount heat for the same temperature difference and area of base plate (copper plate).