Dynamic modelling of ice-based thermal energy storage for cooling applications

The development of accurate dynamic models of thermal energy storage (TES) units is important for their effective operation within cooling systems. This paper presents a one-dimensional discretised dynamic model of an ice-based TES tank. Simplicity and portability are key attributes of the presented model as they enable its implementation in any programing language which would, in turn, facilitate the simulation and analysis of complex cooling systems. The model considers three main components: energy balance, definition of the specific heat curve, and calculation of the overall heat transfer coefficient. An advantage of the model is that it can be adapted to other types of TES units employing phase change materials. The modelling approach assumes equal flow and temperature distribution in the tank and considers two internal tubes only to represent the whole tank-significantly reducing the number of equations required and thus the computation time. Thermophysical properties of water during the phase change and of the heat transfer fluid are captured. The ice-based TES tank model has been implemented in MATLAB/Simulink. A good agreement between simulation results and experimental data available in the literature has been achieved-providing confidence in the validity of the mathematical model.