Literature offers several excellent contributions in view of hydrodynamics and heat transfer characteristics of fluidized beds. Our investigations deal with the achievable wall-to-bed heat transfer rates at a tube bundle heat exchanger immersed in a bubbling bed of Geldart Type B particles. We confirm the findings of other authors, who described the lateral distribution of bed voidage as well as horizontal and vertical particle velocity and heat transfer. The heat transfer coefficients in the core of the bed are significantly higher than they are at the walls. An adapted gas distributor with a non-uniform nozzle-grid was used to overcome the disadvantage of unevenly distributed heat transfer. While the heat transfer coefficients close to the wall are 25-50% lower than in the core region when a uniform nozzle-grid is used, the effect can be fully balanced with the modified gas distributor. We conclude that a more even lateral distribution of heat transfer rates is possible while the overall heat exchange rate remains unchanged. Nevertheless, an increased uniformity in lateral particle mixing may indicate an improvement in heat surface load and mass transfer. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.