Wood‐framed binary eutectic polyethylene glycol ( BEPEG ) as phase change materials for thermal storage

Polyethylene glycol (PEG) is widely used in thermal energy storage, but leakage and lack of stability limit its further development. Wood is widely used as matrix to develop functional composites due to its porous structure and unique composition. In this study, a novel shape-stabilized eutectic phase change material for thermal storage (EPCMTS) with enhanced thermal stability and superior chemical stability was fabricated by incorporating binary eutectic PEG (BEPEG) into porous wood flour (WF). It was found that BEPEG systems composed of PEG600 and PEG1000 at different proportions showed different thermal performances. This EPCMTS at its eutectic point exhibited a melting enthalpy of 45.26 J/g, which is higher than that of incomplete eutectic materials. Its thermal stability was enhanced at eutectic point because the melting temperature of 21.83°C was lower than that of each component. Moreover, the leakage rate can be lowered to only 1.1% at a PEG600:PEG1000 mass ratio of 9:1, which indicated that WF can effectively prevent PEG from leaking. No chemical reaction was detected in both PEG eutectic and WF modification processes. This kind of wood-framed phase change material has broad application prospects in insulation building envelope.