Carbonized-wood based composite phase change materials loaded with alumina nanoparticles for photo-thermal conversion and energy storage

The integration of photo-thermal conversion and thermal energy storage is an efficient way to improve the solar energy utilization. Phase change material (PCM) with excellent thermal storage ability is often used in solar energy storage systems. However, PCMs suffer from liquid leakage, low thermal conductivity and insensitivity to light. This work used sol-gel and high-temperature calcination to modify the carbonized-wood (CW) by alumina nanoparticles loaded in the pores to improve the above issues. The combined microscopic and macroscopic test results showed that the modified carbonized-wood provided a good support structure for the paraffin wax (PW) to prepared carbonized-wood based composite phase change materials (CCPCMs). The CCPCMs exhibit noticeable hydrophobicity as well. The thermophysical properties of the CCPCMs were tested and the results showed that the CCPCMs possessed excellent encapsulation rate (85.98 %–91.65 %), enthalpy of phase transition (166.3–176.6 J/g), and good thermal reliability. By high-temperature carbonization and loading of alumina nanoparticles, the photo-thermal conversion efficiency of CCPCMs was optimized to 95.13 % and the surface overheating was weakened. In the simulation experiment of glass chamber, CCPCMs can store heat while maintaining the uniformity of the chamber's temperature. In conclusion, the novel CCPCMs developed in this work are highly promising in the field of solar thermal utilization and storage.