Experiments were performed on a fluidized bed model with a cross section of 80*85mm and a height of 1.2m. Sand particles were used as a bed material. Measurements of specific air consumption, pressure drop, mean wall temperature, bed temperature distributions and particle sizes have been carried out. Some primary experiments were carried out at ambient temperature to study fluidization characteristics of sand particles. The measurements were taken at near room temperature and ambient pressure using three sand particle sizes dp < /sub> = 2.32, 1.60 1.10mm). Experimental results for heat transfer coefficient and aerodynamic characteristics between immersed bundles of horizontal smooth tubes and air-fluidized beds as medium and different particle sizes were reported. The results were presented as a function of specific air consumption, bed height and bed particle diameter. Empirical equations correlating the pertinent variables has been suggested. The obtained data were compared with experimental results and theoretical models from literature.