Optimized manufacturing process of encapsulating phase change materials in granular form using coating materials and methods

This paper focuses on the development of leak-proof phase change materials (PCM) granules, industrially. Stearic acid (SA) is chosen as the PCM material. The paper first describes the method of impregnating SA into a porous graphite matrix resulting in a composite powder. Various combinations of polymeric coating materials are chosen and their reactivity with the SA is studied. Further, the best polymeric coating was then applied to the composite powder. Three methods are discussed - matrix encapsulation, pan coating, and fluidized bed coating. The granules obtained by all three methods, after coating are then characterized. The thermal properties are compared by measuring phase change temperature, latent heat, and leakage. The melting point of the granules was found to be in the range of 63-65 ℃ indicating that PCM has not undergone any chemical degradation during the processing. Surface morphology was studied to understand the uniformity of the coating.