Numerical simulation of latent and sensible concrete thermal energy storage system

A new type of concrete with PCM (Phase Change Material) thermal energy storage system is presented. The system, developed for industrial applications, is supposed to operate with temperature up to 400 °C and the PCM added mixture presents enhanced performances. A cylindric concrete module was numerically simulated, with the CFD software ANSYS Fluent, and the results were compared with previous experimental tests. A stainless-steel pipe is inserted in the center of the cylinder and the whole system is insulated. The charging stage is obtained by heating the pipe’s surfaces by Joule effect and the module is then cooled with compressed air through the pipe. Two concrete mixtures were tested, with and without PCM addition, in the same conditions, to evaluate their differences. A binary mixture of salts was used as PCMs, composed of 40% of KNO3 and 60% of NaNO3, and they were absorbed by diatomite, a porous fossil flour.