Thermal properties of phase change material from coconut oil and graphene as energy storage for building applications

The aim of this study is to investigate the thermal properties of phase change material (PCM) from coconut oil as energy storage for building applications. Coconut oil is classified as organic PCM from fatty acids made from renewable feedstock. However, low thermal conductivity becomes one of the major drawbacks of organic PCMs and needs to be improved. Graphene can be an effective material to enhance the thermal performance of organic PCMs. In this study, we used coconut oil that has a latent heat capacity of 114.6 J/g and a melting point of 17.38⁰C. PCMs were prepared by sonicating coconut oil into graphene, as supporting material. The mass fractions were 0 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, respectively. The thermal conductivity test was performed using KD2 Thermal Properties Analyzer under different ambient temperatures of 5⁰C, 10⁰C, 15⁰C, 20⁰C, and 25⁰C simulated with circulating thermostatic bath. Latent heat, melting point, the freezing point were determined through DSC testing. Thermal stability was determined using TGA testing. While morphology and chemical structure were examined using TEM and FT-IR, respectively. From this study, the effect of graphene addition to coconut oil indicates fluctuating increase where the highest improvement was seen in 0.3 wt% sample at 20⁰C. Latent heat was decreased by 11% due to molecular movements within the PCM. However, TGA analysis revealed that the composite PCMs showed good thermal durability in building temperature ranges.