Experimental investigation of cascaded thermal energy storage systems using finned encapsulated phase change materials

• Enhanced heat transfer using finned encapsulations in TES systems. • Copper encapsulation shows highest heat transfer during charging/discharging. • Stainless steel encapsulation proves to be the most cost-effective option. • Erythritol and xylitol PCMs offer efficient energy storage at varying temperatures. • Improved TES design maximizes solar energy utilization for industrial applications. In industrial applications, large amounts of thermal energy are required for heating, drying, and processing across a wide range of temperatures. However, the reliance on conventional energy sources for these processes contributes to increased operational costs and environmental impacts. This study addresses the critical need for efficient energy storage solutions to harness and store solar energy for use during non-peak periods, especially in off-summer hours, to reduce dependence on fossil fuels and improve sustainability. The research focuses on developing an advanced thermal energy storage (TES) system utilizing phase change materials (PCMs) to store solar energy at different temperature levels. Erythritol and xylitol are selected as PCMs based on their melting points and suitability for specific temperature requirements. The PCMs are encapsulated in three materials—stainless-steel, copper, brass—with annular fins to enhance heat transfer efficiency. The system's performance is evaluated by analyzing the charging and discharging processes, as well as energy storage and release rates. The results show that copper-encapsulated annular finned containers with erythritol as PCM achieve the highest energy transfer efficiency, recording 3579.6 kJ during discharging and 3901 kJ during charging. Despite this, stainless-steel encapsulation with annular fins proved to be the most cost-effective solution for both charging and discharging phases.