Second Law Analysis of Latent Heat Based Thermal Energy Storage Systems

This chapter concerns the second law analysis of latent heat storage using phase change materials (PCMs). The discussion covers the PCMs and the PCM-based devices and systems. The analyses on the PCMs focused on the irreversibilities of phase change processes particularly due to supercooling, and adding thermally conductive particles or matrixes to enhance the heat transfer process. The analysis of PCM-based devices and systems include three aspects: (a) key evaluation parameters for assessing the performance of latent heat storage devices, and the use of such parameters to optimize geometric designs and device configurations; (b) approaches for enhancing thermal performance of latent heat storage systems, particularly the effectiveness of the cascading use of PCMs, the PCM melting temperature range, and the PCM arrangement; and (c) key processes that give rise to major exergy losses through an exergy balance diagram.