Stearic acid/boron nitride as a composite phase change material for thermal energy storage

Stearic acid (SA) as a phase change material (PCM) can solve the problem of solar energy mismatch in time and space. However, the low thermal conductivity limits its development. To improve the thermal conductivity of SA in thermal energy storage systems, a novel SA/boron nitride (BN) composite PCM was prepared by melting the blending method. Different physical parameters were measured to assess the comprehensive performance of SA/BN. SA/BN thermal properties, microstructure, crystal structure, and chemical stability are characterized using different instrumentation. Results demonstrated that the prepared SA/BN shows a lower melting temperature and a higher solidification temperature compared to SA. Meanwhile, when the loading amount of SA is 88 wt%, the crystallinity and melting enthalpy was 84.36 % and149.34 J·g−1. The thermal conductivity of SA/BN is 2.82 times higher compared to pure SA, which is 0.96 W·m−1·K−1. Furthermore, SA/BN displays excellent cycling stability and thermal stability, the melting and solidification enthalpy changed by 2.89 % and 2.18 % for 50 cycles. The weight loss of SA/BN occurs between 200 and 350 °C, which means that the SA/BN-12 is suitable for building heating.