Experimental phase change analysis of a eutectic KNO3-NaNO3 mixture surrounding a finned tube heat exchanger

Kurzfassung

Phase change materials (PCMs) enable higher thermal energy storage densities than sensible heat storage for processes operating within narrow temperature intervals. Their low thermal conductivity is commonly addressed using finned tube heat exchangers; however, experimental data remain scarce in the 150-300 °C range relevant to steam applications. This work presents a high-resolution experimental method to determine the phase distribution in the cross-section of a PCM volume using infrared thermography. The described test rig is designed for the analysis of a system using the eutectic KNO3–NaNO3 mixture with a melting temperature of 222 °C as PCM, combined with a tree-like aluminum fin structure, which should provide experimental data for the validation of numerical simulation and design tools.