Performance improvement of lauric acid-1-hexadecanol eutectic phase change material with bio-sourced seashell powder addition for thermal energy storage in buildings

Organic phase change materials (PCMs) such as fatty acids and fatty alcohols are often trapped by inherent low thermal conductivity for thermal energy storage in buildings. The present study is devoted to ameliorating this problem from an innovative perspective of introducing bio-sourced additive. To promote performance of binary eutectic PCM comprising lauric acid (LA) and 1-hexadecanol (HD), the composite PCMs are developed, where the powdered seashell waste is added as thermal enhancer, and their thermo-physical properties are characterized via DSC, FT-IR, SEM, TGA, cooling curve analysis, accelerated thermal cycling test together with thermal con-ductivity measurement. Meanwhile, the impacts of two particle sizes, five mixing ratios between two different sizes and two modification approaches of seashell powder (SP) are surveyed meticulously. Experimental results turn out that 80-mesh SP and 300-mesh SP are both capable of providing greater thermal conductivity when dispersed in LA-HD eutectic PCM, and the enhancement level of thermal conduction is even higher for composite PCM containing 300-mesh SP than for composite PCM containing TiO2 powder. Besides, the thermal conduction ability is strengthened to the maximum extent when 80-mesh SP and 300-mesh SP are combined at mass ratio of 3:7, while the same situation also occurs when seashell powder is treated by high-temperature calcination. The resultant composite PCM possesses encouraging melting temperature and melting enthalpy, and its thermal stability and reliability are well approved. Therefore, we conclude that the seashell powder has the expectable competence to realize performance improvement of organic PCM for application in buildings for thermal energy storage.