Influence of Particle Size Distribution of Low-Carbon Flotation Fly Ash on the Phase-Change Thermal Storage Performance

Abstract

This study investigates the influence of low-carbon fly ash particle size distribution on the thermal storage performance of its shaped phase change material (SSPCM). A multi-level particle system was employed, where fly ash particles larger than 50 μm formed the skeletal pore structure, while particles smaller than 50 μm filled the skeletal pores through different grading methods, thereby regulating the pore structure of the composite system. Using decanoic acid–stearyl alcohol eutectic phase change material as the energy storage medium, the loading capacity and thermal properties of fly ash-based composite phase change materials with different particle gradations were systematically analyzed. Results indicate that multi-size synergistic distribution promotes stable pore structure formation and enhances capillary adsorption capacity. When the phase change material loading exceeds 35%, the material's thermal leakage rate can be controlled below 2%, demonstrating excellent thermal stability. The findings demonstrate that rational control of fly ash particle size distribution can effectively enhance its phase change energy storage performance.