This work presents a procedure based on two-dimensional and three-dimensional spatially resolved near-infrared imaging to observe temperature and composition maps in gas solid packed beds subjected to effects of aspect ratio and nonisothermal conditions. The technique was applied to the water vapor flow in a fluidized bed and a packed bed reactor and confirmed uneven water vapor flow channeling and temperature distributions in the core packed bed and in the vicinity of the wall due to flow maldistribution. In addition, the heat uptake and local cross-mixing were experimentally ascertained.