Fatty acids derived from waste cooking oil (WCO) are successfully processed as sustainable phase-change materials (PCMs) for thermal energy storage. This study investigated the conversion of WCO into fatty acid-based PCMs through hydrolysis and hydrogenation, optimizing reaction parameters to enhance thermal properties. A logarithmic model was developed to describe the relationship between hydrogenation time and the adjustment of melting point. The study also examined the correlation between WCO-derived fatty acids (WCOFAs) and their chemical structure, providing insights into optimizing hydrogenation conditions to achieve desired melting points (between 15 °C and 60 °C). The effects of different oil mixtures on thermal characteristics, such as melting point and latent heat, were analyzed to tailor WCOFA-based PCMs for industrial applications. Experimental results indicated that increasing hydrogenation time reduces carbon-carbon double bonds, increasing the melting point and latent heat, with fully hydrogenated WCOFAs exhibiting properties comparable to those of commercial PCMs (∼150 J g-1). This study highlights WCOFAs as cost-effective, environmentally friendly alternatives for thermal energy storage, contributing to sustainable waste management and resource utilization.
Wang et al. (2026) studied this question.