Effect of the mesoporous size, structure and surface on the melting and heat transport properties of solar salt

Molecular dynamics simulations combined with experimental methods were used to summarize the changes of thermophysical parameters such as bulk thermal expansion coefficient, thermal conductivity, specific heat capacity at constant pressure and melting point, which based on the radial distribution function and interaction energy. The micro-mechanisms of the melting and heat transport properties of solar salts at the nanoscale were analyzed. The simulation and experimental results show that the bulk thermal expansion coefficient of solar salt decreases with the increase of the mesopore size. At the same scale, the bulk thermal expansion coefficient of the nanopillar solar salt is smaller than that of the spherical structure solar salt in the nanopore. The raising of the scale enhances the thermal conductivity of the solar salt, but has little effect on the specific heat capacity. The thermal conductivity and specific heat capacity of the CPCM are improved with the increase of Al2O3 in the skeleton. The variation of the skeleton structure has a certain influence on the specific heat capacity of CPCM. The melting point of solar salt shows a trend of increasing and then decreasing with the raising of nanopore size. The change of the mesoporous structure affects the melting point of CPCM. The addition of the porous alumino silicate ceramic skeleton reduces the melting point of the solar salt. And the melting point of the CPCM with larger interfacial binding energy is relatively higher. •Correspondence between microscopic simulation and macroscopic thermal analysis data.•Micro analysis of scale effect on melting and heat transport proportions of CPCMs.•Micro analysis of structure effect on the melting and heat transport proportions of CPCMs.•Micro analysis of surface effect on the melting and heat transport proportions of CPCMs.