Development of a Quasi-2d Variable Resistance-Capacitance Model for Phase Change Material Storage Tanks

A latent heat thermal energy storage (LHTES) system, which uses phase change materials (PCMs) as thermal storage medium, has attracted interests over the past decades due to its high energy storage density. However, a computationally efficient heat transfer model, which is essential for real-time prediction of the thermal performance of LHTES systems, is still lack. Thus this paper presents the development and validation of a computationally efficient dynamic model for PCM storage tanks. The proposed model is built in the form of a thermally variable resistance-capacitance (VRC) network in quasi two-dimension, thus titled as quasi-2D VRC model. Different from available models in previous literature, (i) the parameters of the quasi-2D VRC model can be specified according to the thermal properties of the used materials and the configuration of thermal storage tanks, not driven by operational data; (ii) it can be used to simulate both full and partial charging/discharging processes; and (iii) its computational efficiency can be improved significantly. The accuracy of the quasi-2D VRC model was validated using two published experiments, and its computational efficiency was validated through comparing with other numerical simulation methods. Due to its computational efficiency and accuracy in modelling the thermodynamics in full and partial charging/discharging processes, the proposed model could find applications in real-time prediction, simulation and control of PCM storage tanks