A novel bio-based polyurethane/wood powder composite as shape-stable phase change material with high relative enthalpy efficiency for solar thermal energy storage

A novel bio-based polyurethane (PU)/wood powder (WP) composite is prepared as a shape-stable phase change material (SSPCM) for solar thermal energy storage (TES) applications. Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), polarizing microscope (POM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and accelerated thermal cycling testing were performed to examine the chemical composition and structure, crystalline performances and thermal performances. The results indicate that, with only 3.0 wt% WP content, the PU/WP composites presented remarkable performance on phase change behaviors and thermal stability during PEG solid-liquid phase transition region. The maximum latent heat for PU/WP SSPCMs during melting and freezing process are 134.2 J/g and 132.4 J/g, respectively, and the relative enthalpy efficiency reaches 98.7%. At the same time, the obtained PU/WP SSPCMs exhibited reliable light-thermal conversion and temperature-regulated performance. Thus, the novel bio-based PU/WP SSPCMs displayed a high potential application as solar light absorber in the field of solar thermal energy storage and temperature regulation.