Modeling of Actively Forced Close‐Contact Melting in Latent Heat Storage Systems for Performance Evaluation

PAMM, vol. 26

Abstract

ABSTRACT Latent heat storage systems constitute a promising technology for thermal energy storage applications. They function by absorbing/releasing large amounts of energy during phase changes. A critical metric for these thermal storage systems is the charging and discharging rate. For latent heat storage systems based on a solid–liquid phase change material (PCM), it has been shown that the charging rate can be increased by actively forcing the solid PCM against a heat source. In this work, we focus particularly on the charging process of such a force‐assisted thermal storage system by presenting two methods for estimating its charging rate. The first method comprises a fully resolved coupled numerical model that accounts for fluid flow governed by the Navier–Stokes equations within the liquid PCM, as well as melting, according to a physically consistent interface condition known as the Stefan condition. The second method is an analytical model inspired by existing close‐contact melting solutions. We validate our newly proposed analytical model against the numerical results and compare it with an existing analytical model from the literature. We find that our model is in better agreement with the numerical results compared to the established analytical model. Lastly, we show that the problem can be reduced to a master curve in which the response is a function of the Stefan number alone. The implications of this finding for subsequent modeling efforts are discussed.

Authors 3

1. Jonas Bünning corresponding Aachen Chair of Methods for Model‐based Development in Computational Engineering

   RWTH Aachen University

   Affiliation as printed

   Chair of Methods for Model‐based Development in Computational Engineering (MBD) RWTH Aachen University Aachen Germany

2. Dipankul Bhattacharya Aachen Chair of Methods for Model‐based Development in Computational Engineering

   RWTH Aachen University

   Affiliation as printed

   Chair of Methods for Model‐based Development in Computational Engineering (MBD) RWTH Aachen University Aachen Germany

3. Julia Kowalski corresponding Aachen Chair of Methods for Model‐based Development in Computational Engineering

   RWTH Aachen University

   Affiliation as printed

   Chair of Methods for Model‐based Development in Computational Engineering (MBD) RWTH Aachen University Aachen Germany