Phase change materials(PCMs)are popular solutions to tackle the unbalance of thermal energy supply and demand,but suffer from low thermal conductivity and leakage problems.Inspired by how honeybees store honey,we prop...Phase change materials(PCMs)are popular solutions to tackle the unbalance of thermal energy supply and demand,but suffer from low thermal conductivity and leakage problems.Inspired by how honeybees store honey,we propose artificial“honeycombhoney”for excellent solar and thermal energy storage capacity based on TiN nanoparticles decorated porous AlN skeletonsPCMs composites.The thermal conductivity of composites achieves 21.58 W/(m·K)at AlN loading of 20 vol.%,superior to the state-of-the-art ceramic-based composites.The charging/discharging time is reduced to about half of pure PCMs with shapestability and thermal reliability well maintained over 500 melting/freezing cycles.The underlying mechanism can be attributed to the combination of single-crystal AlN whiskers with few crystal defects and reduced phonon scattering,as well as vertically arranged three-dimantional(3D)heat conduction channels.A rapid and efficient solar thermal storage is also demonstrated with solar thermal storage efficiency achieving a high value of 92.9%without employing additional spectrum selective coatings.This is benefited from high thermal conductivity and full-spectrum solar absorptance of up to 95%induced by plasmonic resonances of TiN nanoparticles.In addition,by embedding LiNO3-NaCl eutectics,the phase change enthalpy of composites reaches as high as 208 kJ/kg,making high energy storage density and fast energy storage rate compatible.This work offers new routes to achieve rapid,efficient,stable,and compact solar capture and thermal energy storage.展开更多
A series of form-stable phase change materials （FSPCMs） comprising paraffin as the latent heat storage material, diurea as the supporting material and base oil as the performance improvement agent were prepared. The...A series of form-stable phase change materials （FSPCMs） comprising paraffin as the latent heat storage material, diurea as the supporting material and base oil as the performance improvement agent were prepared. The diurea was synthesized in the system of paraffin/oil directly. A series of characterization was carried out for a deep understand- ing of shape stability and material properties of diurea-FSPCMs. The results showed that paraffin and base oil were packaged in the three-dimensional supra-molecular structures network which was formed by diurea. The dropping point of the prepared FSPCMs could reach 256 ℃ and the oil separation rate was as low as 1.19% at 100 ℃ for 30 h. The results of thermal properties tests showed that the prepared FSPCMs exhibited excellent thermal stability and the FSPCMs remained solid-like state in the temperature range from 25 to 200 ℃. This study proposes a novel method to prepare high-temperature non-flowing FSPCMs composites and methods to detect the thermal stability and shape stability of FSPCMs, which is helpful in understanding the shape stability mechanism and broadening the potential application of FSPCMs.展开更多
基金the National Key Research and Development Program of China(No.2018YFA0702300)the National Natural Science Foundation of China(Nos.51820105010 and 52076106).
文摘Phase change materials(PCMs)are popular solutions to tackle the unbalance of thermal energy supply and demand,but suffer from low thermal conductivity and leakage problems.Inspired by how honeybees store honey,we propose artificial“honeycombhoney”for excellent solar and thermal energy storage capacity based on TiN nanoparticles decorated porous AlN skeletonsPCMs composites.The thermal conductivity of composites achieves 21.58 W/(m·K)at AlN loading of 20 vol.%,superior to the state-of-the-art ceramic-based composites.The charging/discharging time is reduced to about half of pure PCMs with shapestability and thermal reliability well maintained over 500 melting/freezing cycles.The underlying mechanism can be attributed to the combination of single-crystal AlN whiskers with few crystal defects and reduced phonon scattering,as well as vertically arranged three-dimantional(3D)heat conduction channels.A rapid and efficient solar thermal storage is also demonstrated with solar thermal storage efficiency achieving a high value of 92.9%without employing additional spectrum selective coatings.This is benefited from high thermal conductivity and full-spectrum solar absorptance of up to 95%induced by plasmonic resonances of TiN nanoparticles.In addition,by embedding LiNO3-NaCl eutectics,the phase change enthalpy of composites reaches as high as 208 kJ/kg,making high energy storage density and fast energy storage rate compatible.This work offers new routes to achieve rapid,efficient,stable,and compact solar capture and thermal energy storage.
文摘A series of form-stable phase change materials （FSPCMs） comprising paraffin as the latent heat storage material, diurea as the supporting material and base oil as the performance improvement agent were prepared. The diurea was synthesized in the system of paraffin/oil directly. A series of characterization was carried out for a deep understand- ing of shape stability and material properties of diurea-FSPCMs. The results showed that paraffin and base oil were packaged in the three-dimensional supra-molecular structures network which was formed by diurea. The dropping point of the prepared FSPCMs could reach 256 ℃ and the oil separation rate was as low as 1.19% at 100 ℃ for 30 h. The results of thermal properties tests showed that the prepared FSPCMs exhibited excellent thermal stability and the FSPCMs remained solid-like state in the temperature range from 25 to 200 ℃. This study proposes a novel method to prepare high-temperature non-flowing FSPCMs composites and methods to detect the thermal stability and shape stability of FSPCMs, which is helpful in understanding the shape stability mechanism and broadening the potential application of FSPCMs.
