AbstractHeat transfer coefficients between the bed and an immersed horizontal tube in the grid‐region of a shallow gas‐solid fluidized bed were experimentally and theoretically studied. Experiments were carried out in two fluidized bed columns with inside diameters of 88 and 137 mm, respectively. The fluidized particles tested were sand, limestone and glass beads. Experimental parameters also included particle size, superficial gas velocity, tube diameter, tube location and distributor design. A mechanistic model considering the contributions of jet phase, emulsion phase and dead phase was derived for estimating the grid‐region heat transfer coefficients. Most of the model predictions were found to be within 25% of the experimentally observed