Effect of Multiple Storage Cycles on Heat Transfer in Bubbling Fluidized Beds for Thermochemical Energy Storage

The aim of the present work is to characterize the influence of cycling thermochemical energy storage material, i.e. CaO/Ca(OH)2, on their fluidizability and heat transfer characteristics in the fluidized bed. Previous experimental investigation in a small fluidized bed thermochemical energy storage reactor resulted in a set of particle size distributions for different numbers of storage cycles. These particle size distributions are remodelled with CaCO3 of different particle sizes based on calculated mixing fractions. Remodelled materials are subsequently experimentally investigated in a fluidization test rig, consisting of a glass column with an inner diameter of 140 mm and a total fluidized bed volume of approx. 3 L. Differential pressure measurement and a horizontally immersed overall perimeter heat flux probe are used to characterize fluidizability and wall-to-bed heat transfer between immersed cylinder and bed material. Particle size distributions are successfully obtained from the mixing process. Sauter mean diameters range from 382 μm to 27 μm. Experimental investigation in the fluidization test rig is expected to show improved heat transfer for increasing storage cycles due to a decrease in particle size. This effect is expected to be increasingly superimposed by poor fluidizability due to large contents of fines, ultimately leading to a performance degradation curve.     «

The aim of the present work is to characterize the influence of cycling thermochemical energy storage material, i.e. CaO/Ca(OH)2, on their fluidizability and heat transfer characteristics in the fluidized bed. Previous experimental investigation in a small fluidized bed thermochemical energy storage reactor resulted in a set of particle size distributions for different numbers of storage cycles. These particle size distributions are remodelled with CaCO3 of different particle sizes based on calc...     »