High temperature horizontal rock-bed thermal energy storage: modeling and performances

The aim of this thesis is to illustrate the rock-bed thermal energy storage technology, starting from its possible position and usefulness in the current energy environment, going into its working principle and finally to its modelling through the program COMSOL Multiphysics. In support to this, a real setup of the battery is taken into account and was provided for measurements and observations in one of the laboratories at the Denmark University of Technology (DTU). A particular attention is given to the horizontal configuration of this energy storage and to the application at high temperature, both characteristics of the laboratory battery. With the experimental data were taken from it, a first model is built in order to recreate those real conditions faithfully. This first model is used as a validation of the capability of the program COMSOL Multiphysics to simulate correctly the behaviour of this kind of thermal energy storage and it is then exploited as a base for multiple models. In these, the same horizontal configuration is carried on, but various parameters are changed, including the dimensions, with the purpose of evaluating the performances of the battery, build efficiency curves and thus obtain a general overview on this technology.