Latent thermal energy storage

Continuing the discussion on different methods and mechanisms of thermal energy storage, this chapter will jump into the details of the latent thermal energy storage (LTES) method. In an LTES, a phase change material (PCM) is the heart of the sys­tem; it receives heat and releases it at a constant temperature because the absorbed or released heat is used for changing the phase of the material (usually from solid to liquid and vice versa) instead of increasing or decreasing its temperature in a spe­cific phase. The main strength of this method over the sensible thermal energy stor­age (STES) approach, among others, is the high achievable storage density, as materials require quite a significant amount of heat to change phase compared to that required to increase their temperature. In this chapter, the fundamentals of L TES are discussed, various specific mechanisms and materials commonly used in this thermal energy storage class are introduced, the most recent scientific achieve­ments in this field are presented, and the main industrial applications of L TES sys­tems are introduced. Next, detailed mathematical models for conducting energy and exergy analysis of such units are given. To show how the presented models could be used for simulating the performance of such units, a case study analysis is described, and its results are presented. Finally, a discussion of the future perspec­tive of the L TES method and materials is presented to give a better understanding of the strengths, weaknesses, and opportunities in this field and hopefully shed some light on the research path in this specific area of thermal energy storage.