Optimisation of thermal conductivity of phase change materials by using taguchi method

To date, although research on phase change materials (PCM) are still widely carried out, study on different type of phase change materials system is yet to be performed due to the complexity of mixture properties. Thus, right parameters are vital to generate a product with high quality especially with balanced thermal properties. In this study, a comprehensive approach known as Design of Experimental (DoE) has been applied efficiently on relevant stages, starting from the material formulation and processing stage until the material characterisation stage. Few control factors directly affecting thermal conductivity were chosen namely types of PCM wax, percentage weight of graphene, mixing time and speed. The optimised composition was obtained through verification experiment whereby the thermal conductivity had increased by as much as 9.4 % compared to pure paraffin. From the Analysis of Mean (ANOM) and Analysis of Variance (ANOVA), weight of graphene and types of wax had the most significant effects for the thermal conductivity with contribution percentages of 60% and 31% respectively. Results shown thermal conductivity increase proportionally with the percentage weight of graphene. Optimum results are obtained when the type of PCM is paraffin wax and percentage weight of graphene is 5wt%, while the mixing time and speed does not show any significant effect on enhancing thermal conductivity. Furthermore, melting point does not show any significant changes. However, there is a decreasing in latent heat compared to the pure PCMs. The experimental optimum result of thermal conductivity performed better than the predicted optimum results while in comparison the addition of silicone oil gives a better latent heat compared to the addition of mineral oil. This research has shown that the addition of graphene will enhance the thermal conductivity and modify the thermal properties of the PCMs