Characterization of Bio-Based Phase Change Materials for Solar Energy Applications
Abstract
Solar radiation is the primary energy source on Earth and plays a crucial role in decarbonizing the energy matrix, but the intermittency of this source makes energy storage indispensable, with thermal energy storage emerging as a promising technology. Among the storage types, latent thermal energy storage, employing phase-change materials, stands out due to its high energy density and nearly isothermal heat transfer, making these materials suitable for temperature management applications. Despite the predominant use of paraffins, derived from fossil fuels, bio-based phase-change materials, such as lauric acid and vegetable waxes, have emerged as sustainable alternatives. However, several compounds remain unexplored, and their thermophysical properties are still unknown. To address this gap, this study reports, for the first time, the characterization of three different compositions of commercial coconut waxes. The latent heat and phasechange temperature are determined using differential scanning calorimetry. Density and viscosity are measured as a function of temperature with specific apparatus. Lastly, the measured properties are used to comparatively asses the performance of the materials during the melting process, through the use of Rayleigh and Nusselt numbers.
Keywords
solar energy, thermal energy storage, bio-based, phase-change materials, natural waxes