State estimation for the thermal storage in phase change materials containing nanoparticles

Considerable amount of thermal energy can be stored when a material undergoes phase change. Paraffin, water, salt hydrates and sugar alcohols are examples of phase change materials (PCM) commonly used for thermal storage, with melting temperatures that can be suitable for several practical applications. In this work, a state estimation problem is solved by using the Particle Filter method, in a physical problem involving phase change of a material with a dispersed phase, like nanoparticles. The equations of heat and mass transfer are coupled through the interface conditions at the moving phase change boundary. A numerical technique based on the enthalpy method was implemented for the solution of the forward problem. The state estimation problem was solved in this work with simulated measurements of temperature and of the solid-liquid interface position, by using an algorithm that allows for simultaneous estimation of state variables and model parameters.