Investigation on thermal performance of epoxy resin encapsulated eutectic hydrated salt/expanded perlite composite phase change materials for thermal energy storage

In the field of building energy efficiency, hydrated salts are widely used as phase change materials (PCMs) to facilitate efficient energy storage and release, particularly within passive solar thermal energy systems. However, liquid phase leakage of hydrated salts is prone to occur during the phase change process, which can negatively impact overall performance. In this study, disodium hydrogen phosphate dodecahydrate (DHPD) and sodium carbonate decahydrate (SCD) were selected as PCMs to synthesize a eutectic hydrated salt (EHS) at a mass ratio of 6:4. EHS were adsorbed into expanded perlite (EP) by vacuum impregnation method to obtain EP/EHS composite phase change materials (CPCMs). Subsequently, EP/EHS CPCMs were encapsulated using a combination of epoxy resin (ER) and fly ash, resulting in the development of novel ER/EP/EHS CPCMs with a phase change temperature of 23.73 degrees C and a latent heat of 92.87 J/g. Leakage tests revealed that ER/EP/EHS(70 %) CPCMs exhibited excellent leakage resistance. In addition, compared to EHS, the supercooling of ER/EP/EHS(70 %) CPCMs decreased by 3.92 degrees C, effectively alleviated the supercooling phenomenon. After 1000 thermal cycles, the latent heat of ER/EP/EHS(70 %) CPCMs was reduced by only 10.79 %, indicating outstanding thermal cycling stability.