Thermal energy storage in microencapsulated phase change materials in fluidized bed for solar energy applications

Fluidized beds are used in chemical industries for effective heat and mass transfer applications. They can also be used in thermal energy storage (TES) to offer fast and efficient way of exploiting renewable energy sources. Microencapsulated PCMs can serve as TES medium and as the fluidized phase in these applications. There are few experimental studies that investigated using fluidized bed for thermal energy storage. These studies show that properties of microencapsulated PCMs need to be adjusted for use in fluidized bed. Among the microcapsule properties that are important in this application are dimensions, thermal conductivity, thermal stability and durability. In this paper, the performance of an experimental air-fluidized bed of microencapsulated PCM as a thermal storage system is being investigated at different storage temperatures of 55°C and 65°C. The results show that the use of microencapsulated FDMs corresponding to A-type and C-type particles according to the Geldart scheme is possible in TED. The fluidization process did not affect the morphology of the microencapsulated FDMs. Storage and recovery could be accomplished very fast at efficiencies reaching 81%.