Normalized Dynamic Characterization and Application of Multiple Heat Storage Materials Based on Standard Thermal Resistance

Abstract

Based on the standard thermal resistance and the heat current method, the transient heat transfer thermal resistance between the heat storage material and the heat transfer fluid is deduced. Through analog circuit analysis method, the transient heat current model and dynamic response time constant of heat storage-heat exchange processes are obtained. Based on this model, the node temperature is introduced for refining the heat transfer thermal resistance, and the transient heat current model of the third-order circuit coupled with the heat storage and heat transfer processes is obtained. Through numerical simulation verification and application comparison analysis, it is found that the normalized dynamic model based on multiple time constants is feasible to characterize the dynamic characteristics of heat storage materials, and can directly compare and analyze different heat exchange and heat storage materials. The case study found that when exchanging heat with solid heat storage materials, the dynamic heat exchange capacity of liquid metal is better than that of molten salt, while the heat exchange between air and ceramic materials reaches a steady state faster than that of water vapor and CO₂.