Experimental Validation of Switched Moving Boundary Modeling of Phase Change Thermal Energy Storage Systems

Abstract

Thermal Energy Storage (TES) devices use Phase Change Materials (PCMs) to store and release thermal energy. Control-oriented models are needed to predict the behavior of TES devices and experimental validation is necessary to demonstrate the predictive capabilities of these models. This paper presents an experimental validation of a switched Moving Boundary (MB) approach for modeling TES devices, where the dynamics of the device are captured with fewer states than traditional models. A graph-based modeling approach is used to model heat flow, while the moving boundary captures the time-varying liquid and solid regions of the TES. The model uses a Finite State Machine (FSM) to switch between four modes of operation based on the State-of-Charge (SOC) of the TES. Results show that the switched MB approach has similar accuracy and lower computational cost compared to traditional modeling approaches when predicting the SOC of an experimental TES device.