Thermal stress analysis of PCM encapsulation for heat recovery of high temperature waste heat

For efficient heat recovery of high temperature waste heat in the form of latent heat, the stable utilization technology of encapsulated phase change material, PCM, without leak was studied. In the experiments, lead pellets were selected as a PCM, then encapsulated by a nickel film based on an electroplating method, and next were tested by cyclic heating for practical use. At the same time, thermal stress model was developed, validated by the measured data and implemented to study the effect of the film thickness on the strength of capsules. The results of the cyclic test showed that the obtained PCM has enough strength by increasing the film thickness or decreasing PCM diameter. The developed stress model also well predicted the relationship between the film thickness and PCM diameter for estimating the required thickness of the Ni layer. The developed methodology will be useful for designing the encapsulation of any PCMs.