Experimental validation of a lower order model for a flat-plate latent thermal energy storage heat exchanger

Abstract

Latent thermal energy storage systems have seen a large amount of interest from a broad range of applications. Design and sizing of these systems however, remains difficult as finite volume methods are limited by computational resources. Furthermore, classic heat exchanger design methods are not applicable to storage systems as these design methods are based on a steady state analysis. The present paper proposes a computationally efficient modeling method that can deal with both the transient nature of the operation of the storage system and large domain sizes. The model is based on three previously developed separate sub-models, which are connected through a space-series approach. An essential new aspect of this work is the application of the method to a flat-plate latent thermal energy storage heat exchanger, for which a large experimental data set is available, including both melting and solidification experiments. Additionally, the model incorporates heat losses, which were not considered in previous models. The model predictions of the outlet temperature are on average within 1.2 K with the measured outlet temperature with the largest deviations at the start of the (dis)charging and at the end of the phase change. Further research is needed to refine the representation of phase change dynamics and heat losses to improve predictive accuracy. Despite these limitations, the model effectively predicts outlet temperature in most cases, while requiring minimal computational effort. Unlike finite volume methods, its computational cost remains independent of system size.