As cheap and renewable sources,the exploitation of biomass resources was of great value in phase change energy storage.In this study,hemp stems were converted into biochars with three-dimensional multi-level anisotrop...As cheap and renewable sources,the exploitation of biomass resources was of great value in phase change energy storage.In this study,hemp stems were converted into biochars with three-dimensional multi-level anisotropic pores through a temperature-controlled charring process,which were used as supports for polyethylene glycol(PEG6000)to form shape-stable composite phase change materials(ss-CPCMs).It is shown that the ss-CPCMs using anisotropic hemp-stem-derived biochar obtained at a carbonization temperature of 900℃as a support has high PEG6000 loading rate(88.62wt%),large latent heat(170.44 J/g)and favorable thermal stability owning to its high surface area and hierarchical pores.The biochar-based ss-CPCM also has good light absorption ability with a maximum solar-thermal conversion efficiency of 97.70%.In addition,the different thermal conductivities in the transverse and longitudinal directions of ss-CPCMs reflect the unique anisotropic structure.This work can not only improve the high-value utilization of biochars,but also provide the ss-CPCMs with excellent performance for solar-thermal conversion and storage systems.展开更多
基金the National Natural Science Foundation of China(51890893)Fundamental Research Funds for the Central Universities(FRF-TP-20-005A3).
文摘As cheap and renewable sources,the exploitation of biomass resources was of great value in phase change energy storage.In this study,hemp stems were converted into biochars with three-dimensional multi-level anisotropic pores through a temperature-controlled charring process,which were used as supports for polyethylene glycol(PEG6000)to form shape-stable composite phase change materials(ss-CPCMs).It is shown that the ss-CPCMs using anisotropic hemp-stem-derived biochar obtained at a carbonization temperature of 900℃as a support has high PEG6000 loading rate(88.62wt%),large latent heat(170.44 J/g)and favorable thermal stability owning to its high surface area and hierarchical pores.The biochar-based ss-CPCM also has good light absorption ability with a maximum solar-thermal conversion efficiency of 97.70%.In addition,the different thermal conductivities in the transverse and longitudinal directions of ss-CPCMs reflect the unique anisotropic structure.This work can not only improve the high-value utilization of biochars,but also provide the ss-CPCMs with excellent performance for solar-thermal conversion and storage systems.
