Binary decanoic acid/polyethylene glycol as a novel phase change material for thermal energy storage: Eutectic behaviors and energy conservation evaluation

This work developed a novel decanoic acid/polyethylene glycol binary eutectic (DA-PEG) phase change material (PCM) for thermal energy storage, wherein the mass ratio of DA and PEG was 1:1. DSC results indicated that DA-PEG eutectic had a suitable phase transition temperature of 22.9 °C for building thermal comfort, and its latent heat of 173.9 J/g was relatively large. Moreover, DA-PEG eutectic PCM had a superior crystallinity as compared to pure PEG, which was confirmed by the results in terms of supercooling degree, relative exothermic capacity and crystallization kinetics. ATR-FTIR and Raman spectra were used to reveal the mechanism behind. It turned out that the improved crystallization behaviors of PEG were achieved by the promoting effect of the intermolecular hydrogen bonding between DA and PEG on the ordered arrangement of PEG long chain. Furthermore, DA-PEG eutectic PCM presented good thermal and chemical stability in long-term use. Besides, energy and environmental assessment suggested that DA-PEG eutectic exhibited high cost performance and great potentials for energy conservation and emission reduction used in solar passive building.