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 degrees 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 intermo-lecular 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.