Performance assessment of thermal energy storage system for solar thermal applications

Low-temperature and solar-thermal applications of a new thermal energy storage system (TESS) powered by phase change material (PCM) are examined in this work. At varying mass flow rates (0.0119 kg/s and 0.00277 kg/s) and heat transfer fluid (HTF) temperatures (75 °C and 85 °C), three distinct PCMs-paraffin wax, fatty acid, and a cascaded combination of both-had their charging and discharging properties studied. Evaluated across a 240-minute charging and discharging cycle were key performance parameters including energy efficiency, exergy efficiency, entransy analysis, and heat transfer efficacy. According to the results, higher HTF temperatures reduce exergy efficiency because to increased entropy formation even when they raise charging rate. Moreover, thermodynamic performance of the cascaded PCM system increased heat transfer efficiency by 100% and by 30% respectively. Moreover, charging and exergy efficiencies were realized as at 85.2% and 47.5% respectively. The liquid percentage of the PCM was found to be 0.85 under a mass flow rate of 0.0277 kg/s after 200 min of charging. These findings demonstrate the possibility of cascaded PCM-based TESS to optimize solar energy storage for usage requiring high efficiency and constant heat transfer.