In this study, Bio-based PCMs were prepared by the stirring of carbon nanomaterials, such as exfoliated graphite nanoplatelets (xGnP) and carbon nanotubes (CNT), in liquid Bio PCM, for high thermal conductivity. Carbon nanomaterials were added to Bio PCM at different mass fractions (1.0, 3.0 and 5.0 wt%). The microstructures were characterized using scanning electron microscopy (SEM), and showed good dispersion of Bio-based PCM composites. Fourier transform infrared spectroscopy (FT-IR) results showed good compatibility between Bio-based PCM and prepared carbon nanomaterials. The thermal conductivities of composites were significantly increased, as the carbon nanomaterials loading contents increased. Differential scanning calorimetry (DSC) analysis results indicated that Bio-based PCM/xGnP composites maintained their large latent heat values and suitable phase change temperatures, due to large surface area, and good dispersion of carbon nanomaterials. TGA analysis revealed that Bio PCM composites had good thermal durability in the working temperature ranges. Therefore, Bio PCM composites can be considered as suitable candidates for latent heat thermal energy storage, with high thermal performance. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.