A new combined infrared/particle image velocimetry/digital image analysis (IR/PIV/DIA) measuring technique for investigating heat transfer in gas–solid fluidized beds has been recently developed. This new technique gives insightful information and quantitative data on particle volume fractions, particle volume fluxes and temperature distributions in fluidized beds for CFD validations. The current paper compares simultaneous thermal and hydrodynamic data of a pseudo 2-D fluidized bed obtained using this new technique with results from CFD–DEM simulations. An extensive series of time-averaged volume fractions, volume fluxes and temperature distributions as well as instantaneous profiles are presented. This detailed comparison between the experimental and simulated profiles shows the capabilities of state-of-the-art CFD–DEM simulations, and pinpoints where simulation (and also measurement) techniques still can be improved.