Renewable approaches to building heat: exploring cutting-edge innovations in thermochemical energy storage for building heating

Thermochemical energy storage (TCES) emerges as a promising solution for building heating, offering superior energy storage density compared to conventional methods like sensible or latent heat. This approach not only enhances energy management but also strengthens energy security, reduces greenhouse gas emissions, and supports Net -Zero energy initiatives. Salt hydrate -based TCES technology is praised for its impressive energy storage density and potential for long-term preservation with minimal heat loss. Despite extensive research, achieving commercial viability requires further refinement, prompting studies to address technical limitations. This review delves into recent advancements in long-term thermochemical energy storage using salt hydrates, exploring both material and system aspects. Various thermochemical materials, including pure salt hydrates, mixed hydrate salts, and custom composites, undergo assessment alongside their thermal performance. Highlighted are optimal composites like CaCl2@expanded perlite, boasting 30 % salt content and achieving a high energy density of 2166 kJ/kg at 20 degrees C and 80 % RH. Another noteworthy composite, MgSO4-MgCl2@porous carbon, with 60 % salt content, demonstrates a high energy density of 1840 kJ/kg at 30 degrees C and 60 % RH. Despite significant progress in this research domain, substantial efforts are still required to address challenges related to technology upscaling and the techno-economic reliability of TCES systems.