High-temperature porous phase change heat storage ceramsite: the crucial impact of pore structure

Abstract

Phase-change heat storage technology contributes to balancing supply and demand, thereby enhancing overall system efficiency and stability. However, phase change materials may leak or corrode theirs containers during the phase change process, necessitating encapsulation to improve thermal and structural stability. This study employed a porous adsorption method to investigate the effects of different pore structure designs on high-temperature porous phase change heat storage ceramsite, achieved by controlling the content and distribution of the pore-forming agent. To further suppress leakage, a silica sol coating technique was introduced for surface modification. The results showed that as the pore-forming agent content increased, the adsorbance of the non-structurally designed porous ceramsites gradually increased, reaching a maximum at a sintering temperature of 1050 ℃. A sample composed primarily of fly ash with 30 % fine coal powder achieved an adsorbance of 124 %, a phase transition temperature of 146.09 ℃, a latent heat of 54.91 J/g, a thermal storage density of 379.29 kJ/kg, and a compressive strength of 4.46 MPa. Atmospheric encapsulation using JN-40 silica sol yielded the best results, reducing the leakage rate to as low as 1.36 %. Therefore, through the integration of pore structure optimization and surface modification, high-temperature porous phase change heat storage ceramsite exhibits enhanced performance, offering robust support for the advancement of new energy technologies.