Preparation And Performance Study Of Phase Change Energy Storage Wood Particle Composites For Rapid Heat Storage And Release

In order to solve the problems of uneven distribution of phase change materials and poor thermal conductivity of wood phase change energy storage materials,this paper uses wood particles as the carrier and polyethylene glycol（PEG）as the phase change material,and through screening the compounding ratio of PEG solution and adjusting the concentration of Fe₃O₄ particles,a rapid heat storage and release phase change energy storage wood particles composite material with room temperature phase change and high enthalpy is obtained.This has theoretical value and practical significance for the research of wood phase change energy storage materials and building energy conservation.The main research findings are as follows:（1）Phase change energy storage wood particles composites were obtained by vacuum pressure impregnation and one-step hot pressing using poplar particles as the shaped adsorbent material and single molecular weight PEG as the phase change material.The results showed that the poplar particles solved the leakage problem of the phase change material to a certain extent by physical adsorption,and the enthalpy of the composite increases gradually as the molecular weight of PEG increases.When the molecular weight of PEG is 1500,the enthalpy of the composite is the highest,reaching 145.6 J/g.However,the melting phase change temperature is 46°C,which is not suitable for human living environment.When the molecular weight of PEG is 800,the melting and freezing temperatures of WPCM800-6 are 10.05°C and 24.68°C respectively.The phase change temperature is suitable,but the enthalpy of phase change is low.（2）To solve the problem of high phase change temperature and low enthalpy of single molecular weight PEG,phase change energy storage wood particle composites were obtained by preparing binary compound solutions of PEG800 and PEG1500.The results show that the binary compounded PEG phase change energy storage wood composites have high enthalpy and suitable phase change temperature,and the enthalpy and phase change temperature of the composite gradually increase with the increase of PEG1500 content in the compounded solution.When the ratio of PEG800 to PEG1500 was 1:3,the enthalpy of melting and freezing of CWPCM-3 was 76.72 J/g and 78.74 J/g respectively,and the phase transition temperatures of melting and freezing were 27.77°C and 13.58°C respectively.The temperature test shows that the binary compound PEG phase change energy storage wood particle composites have a clear temperature constant interval during the temperature rise and fall,and has good performance of heat storage and release.（3）In order to obtain a rapid heat storage and release phase change energy storage wood particles composite material with photothermal conversion performance,Fe₃O₄ nanoparticles were introduced into the composite.The results showed that Fe₃O₄ nanoparticles significantly improved the thermal conductivity and photothermal conversion efficiency of the composite.When the addition of Fe₃O₄ is 5%,the thermal conductivity of the composite is 0.3545 W/（m*K）,which is 2.25 times that of pure wood.At the same time,the addition of Fe₃O₄ nanoparticles also improved the physical and mechanical properties of the composite,such as dimensional stability and hardness.