Research on the performance of heat storage devices under different melting point phase change materials in industrial waste heat utilization

Phase change heat storage technology can provide effective solutions for temporal and spatial mismatch in the utilization of industrial waste heat and achieve efficient heat transportation. However, in view of the diverse characteristics of industrial waste heat, it is urgent to conduct research on the utilization of waste heat at different temperatures. Building upon existing theories, this paper innovatively establishes a numerical model for multi-melting-point phase change heat storage materials (PCM), taking into account both temperature of the heating surface and melting points of the heat storage materials. The melting process of the selected materials was simulated and the results were discussed. The coupled thermal performance of different heating surfaces and melting point temperatures was quantitatively clarified based on the analysis of the results of numerical models. The research results show that different heating surfaces have remarkable influence on the melting efficiency. At the melting point of 50?, under the heating surface at 75?, the complete melting time is only 3360 seconds, which is 31% of the complete melting time when using a heating surface at 60?. Furthermore, when the heating surface temperature reaches a certain level, the influence brought by melting point gradually diminishes. Evolution diagrams of the temperature field visually demonstrates the positive correlation between the intensity of natural convection and the heat transfer temperature difference. Finally, it was found that latent heat mainly determines the heat storage capacity of PCM and choose materials with appropriate melting points can improve the heat storage rate. By conducting research on the new type of heat storage device with multiple heating surfaces and multiple melting points, this study provides guidance for optimizing the heat utilization efficiency in practical engineering applications.