Experimental investigation in the selection of phase change materials based on thermal stratification effect in thermal energy storage system.

This study aims to evaluate the effects of thermal stratification on thermal energy storage (TES) systems during the charging process and choose suitable phase change materials (PCMs) for various layers. The research revealed that fiberglass insulation of 60 mm thick significantly decreased natural convection losses and increased the TES system's potential for energy recovery. For constant heat load, the charging time increased with increasing HTF inlet temperature, but remained constant for the first TES layer at a specified flow rate, resulting in increased storage capacity with minimal heat loss to the surroundings. The solar collector efficiency was shown to be dependent on solar radiation and collector efficiency, with peak efficiency seen at specified periods. The lowest melting point of PCMs at each layer 68°C, 62.7°C, 57°C, and 50°C was chosen based on temperature graphs. For comparing stratification behavior, the "MIX" number versus non‐dimensional charging time plot was effective. Additional experiments are needed to assess the selected PCMs' charging and discharging properties. [ABSTRACT FROM AUTHOR]