Synthesis and characterization of thermochemical storage material combining porous zeolite and inorganic salts

Abstract

Thermal energy storage (TES) has the potential to decarbonize the heating sector facilitating the penetration of renewable energy sources, in particular solar thermal energy. In this paper we present a study on thermochemical storage material (TCM) composed of inorganic salts hosted in the porous matrix of zeolite 13X with the addition of carbon material. A series of composites containing different amounts of inorganic salts - MgCl2, MgSO4 - graphite and carbon nanotubes were prepared by impregnation method. Energy storage and adsorption/desorption rates were assessed using simultaneous thermal analysis (STA) by coupling thermogravimetric (TG) and differential scanning calorimetry (DSC). Microstructure and composition were assessed through scanning electron microscopy and energy-dispersive X-ray spectroscopy. With our composite material we achieved exceptional energy density of 400 kJ/kg within the temperature range 30-150°C. Such features make the material an interesting option for thermal storage in buildings. We attribute the behaviour of the material to to the combination of large zeolite specific area coupled with the heat of sorption of MgCl2, MgSO4.