Validation of numerical model for latent thermal storage operation and analysis of heat charge and discharge in TRNSYS

A convenient solution to increase energy density of conventional water thermal storage is with the use of encapsulated phase change materials that can be installed in the existing water tank through a flange. That kind of solution brings quick and pragmatic solution of energy density improvement but it leads to more complicated operation of thermal storage from state-of-charge point of view. The simulations can help in better understanding of thermal storage operating conditions. That is why the focus of present research is on simulations under different initial conditions with numerical model that was validated with measurement results. The investigation took place on water thermal storage tank with encapsulated phase change materials (PCM) that represented 30% of the thermal storage volume. The measurements of a 100 l water tank with 190 spherical capsules filled with PCM (hydrate salt mixture) were performed. The numerical model for latent thermal storages was used in TRNSYS environment and was adjusted according to the boundary and initial conditions of the experimental system and measurement conditions. The results of simulations were compared with the measurements in order to perform the validation of the numerical model. After successful validation, the simulations of different initial water temperatures to the thermal storage system were made in order to analyse its heat charge and discharge process.