Investigations on the stability of metallic cans for PCM macro-encapsulation

The storage of renewable thermal energy is becoming increasingly important. Due to the discrepancy between supply of renewable energies and demand, thermal storage systems are necessary. Macro-encapsulated phase change materials (PCM) can be used as a thermal energy storage and provide an opportunity to balance this energy discrepancy. Commercial capsule materials for PCM have either adverse material properties such as low thermal conductivity (plastics) and/or are very expensive. This paper presents initial results of the examination of the suitability of a low-cost metallic packaging material with a wax coating on the outside layer for macro-encapsulation of PCM. Two different capsule geometries were filled with a salt hydrate and subjected to thermal cycling. During the thermal cycling process, the tightness of the capsules was investigated via measurements of the electrical conductivity of the surrounding water. Additionally the thermal performance of the capsules was assessed.