Anchoring phase change interface enhances solar thermal energy storage.

Area of Science:

• Materials Science
• Renewable Energy Engineering
• Nanotechnology

Background:

• Solar thermal energy storage using phase change materials (PCMs) is crucial for decarbonization but suffers from declining charging rates due to interface recession.
• Conventional PCMs face challenges with increasing thermal resistance as the solid-liquid interface moves away from the heat source.

Purpose of the Study:

• To develop a novel solar thermal energy storage system that overcomes the limitations of diffusion-limited charging.
• To achieve rapid, efficient, and continuous solar thermal charging by anchoring the phase change interface.

Main Methods:

• Fabrication of core-shell composite phase change particles (CPCPs) with a photothermal MnFe2O4 shell and a high-conductivity MgO/h-BN/NaCl-KCl core.
• Utilizing a dynamic circulation system to continuously renew the irradiated surface of the CPCPs.
• Characterization of particle properties including solar absorptance, thermal conductivity, and energy storage density.

Main Results:

• CPCPs achieved a solar absorptance of 91.1% and an effective thermal conductivity of 6.84 W m−1 K−1.
• The system demonstrated a solar thermal storage efficiency of 49.7%, a 26-fold improvement over conventional methods.
• A charging power of 0.54 kW was achieved under 1.08 kW solar input, showcasing continuous energy storage.

Conclusions:

• The developed CPCPs and dynamic circulation system enable a paradigm shift to an "interface-anchoring" mode for solar thermal energy storage.
• This approach significantly enhances charging efficiency and rate, offering a promising solution for sustainable energy solutions.
• The study highlights the potential for scalable and efficient solar thermal energy storage through innovative material design and system engineering.