Preparation and characterization of Beewax/PEG as eutectic organic phase change materials for thermal energy storage

PCMs store latent thermal energy to maintain temperature stability by absorbing and releasing heat during phase transitions, enhancing solar collector efficiency by storing excess thermal energy. PCMs include inorganic, organic, and eutectic types; eutectics, with a consistent phase transition temperature, are ideal for controlled temperature applications. While organic eutectic PCMs (EPCMs) such as paraffin offer high storage density but can produce pollutants. Substituting petroleum-based paraffin with eco-friendly PCMs could reduce greenhouse gas emissions by 45–50 %, highlighting the demand for sustainable alternatives.

Beeswax (BW) and polyethylene glycol (PEG) were selected for this study due to their low toxicity, biodegradability, and compatibility with encapsulation techniques, which make them ideal candidates for flat-plate solar collector integration. This combination aligns with green chemistry principles, offering an environmentally friendly alternative to paraffin-based PCMs while maintaining desirable thermal properties. Additionally, BW-PEG blends show improved biocompatibility and potential for enhanced thermal stability compared to conventional organic and inorganic PCMs. A similar study [1] is considered for selection criterion.

This study represents a significant advancement by exploring the full compositional range of BW and PEG, varying from 0 % to 100 % for each component, to optimize melting points, latent heat capacities, and thermal stability for energy storage applications. Unlike existing studies, which often focus narrowly on thermal properties, this research addresses the interplay between material ratios and key properties, including biocompatibility and long-term thermal behaviour.

The primary aim is to develop and characterize BW-PEG eutectic blends tailored for flat-plate solar collectors. Detailed analyses of melting behaviour, thermal conductivity, latent heat capacity, and phase change characteristics were conducted using methods such as Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). This holistic approach establishes a foundation for sustainable PCM development, advancing beyond existing literature by integrating thermal stability and biocompatibility considerations into PCM design.