An experimental and numerical study was carried out using a model refrigerator in which heat is transferred by natural convection. This transfer takes place between a cold vertical wall and the other walls, which are exposed to heat losses. Simulations using CFD software was undertaken supposing a constant cold wall (evaporator) temperature, and laminar 3D-flow and taking into account heat transfer by radiation. Two cold wall temperatures were studied: 10°C and 0°C. Two configurations were investigated: empty model Refrigerator and model refrigerator filled with 4 blocks of hollow spheres. The comparison of air temperature profile in these 2 cases makes it possible to study the influence of product item. Temperature stratification in the vertical direction with warm zone at the top of the model refrigerator and cold zone at the bottom was observed for all cases (empty and loaded model refrigerator). Air circulates downward along the cold wall and upward along the other sidewalls. Air also circulates horizontally form the sidewalls to join the cold wall but the velocity is very low (