Abstract:

Paraffin wax is an organic phase-change material with high heat storage density, but its low thermal conductivity and easy leakage limit its further development. To improve the thermal conductivity and anti-leakage properties of a paraffin phase-change material (PCM), Al₂O₃ fibers as the thermal conductive fillers were synthesized via a template method using natural fibers. The composite PCM was synthesized using a simple vacuum impregnation method. The microstructure, thermal conductivity, phase-change cycle stability, anti-leakage performance, and thermal response performance of Al₂O₃ fibers/paraffin PCMs were evaluated. The results show that the thermal conductivity increased linearly with the Al₂O₃ fiber content. Particularly, the α-Al₂O₃ produced via sintering at a high temperature of 1200 ?℃ exhibited higher thermal conductivity than the γ-Al₂O₃. When the mass ratio of α-Al₂O₃ reached 45% (mass), the thermal conductivity increased to 0.69 W/(m·K), which was 290% compared to pure paraffin. After 100 thermal cyclic tests, the phase-change enthalpy of the Al₂O₃ fibers/paraffin PCMs remained almost unchanged, indicating that the composite had good cycle stability. As the result of the leakage and thermal response tests, the composites filled to 30% and 45% also showed, good shape stability and heat transfer property. This will promote their practical application in thermal energy storage.

Key words: phase-change material, composites, biotemplating, heat storage, heat transfer