Thermal conductivity and heat transfer performance enhancement of phase change materials (PCM) containing carbon additives for heat storage application

• PCMs with carbon additives including MWCNT, Graphite and Graphene are manufactured.
• The thermal conductivity of PCM is enhanced up to 21.5% in the case of Graphene of 0.1 vol%.
• Graphite is the most promising additive for heat transfer enhancement of stearic acid among three carbon additives.

In thermal storage system, a high thermal conductivity of Phase Change Materials (PCM) is required to complement the crystallization phenomenon of the PCM during the discharging process. In this study, PCM with carbon additives, Multi-walled Carbon nanotube, Graphite and Graphene, are manufactured and the thermal conductivity of the PCM is measured by the transient hot-wire method for thermal storage application. The thermal conductivity of the PCM is enhanced by adding the carbon additives, and the effect of Poly Vinyl Pyrrolidone (PVP) as a dispersion stabilizer on the thermal conductivity is evaluated. It is found that the heat transfer rate enhances up to 3.35 times in the case of Graphite at 5.0 vol%. It is finally concluded that Graphite is the most promising candidate for heat transfer enhancement of stearic acid among three carbon additives even though Graphene gives the highest thermal conductivity enhancement.