Preparation And Heat Transfer Study Of Phase Change Wood Plastic Composite Based On Shape Stabilized Fatty Acid Eutectic

Phase change material has the function of adjusting temperature and saving energy.The combination of phase change material and buildings can reduce building energy consumption.Wood plastic composites are widely used in the field of building materials because of its outstanding performances.The introduction of phase change material into wood plastic composites can provide new building materials for building energy conservation.The research on phase change wood plastic composites was carried out.The shape stabilize effects of wood flour and polyvinyl chloride microcapsule on the fatty acid eutectic were explored,respectively.The shape stabilized phase change material and microcapsule were introduced into wood plastic composite,and the phase change wood plastic composite was developed.The heat transfer mathematical model was employed to simulate and analyze the temperature regulation and energy saving function of phase change wood plastic composite used in building heating environment.The main conclusions are as follows:(1)Fatty acid eutectic was prepared.Results show that the phase change temperature of capric acid-palmitic acid eutectic is 23.5 ?.The phase transformation process is regular,the latent heat is159.8 J/g.There is just crystal reaction between capric acid and palmitic acid and no chemical change occurred.The change of phase change temperature after 1500 times of thermal cycling is less than 1 ?,and the change of latent heat is less than 3 %.(2)Fatty acid/wood flour shape stabilized phase change material was prepared.When the vacuum impregnation ratio of fatty acid to wood flour is less than 0.8:1,the mass loss is less than5 % after heating.The influence of wood flour on the phase change properties of fatty acids decreases with the increase of impregnation ratio.The compatibility between fatty acids and wood flour is good,and there is no chemical reaction between them.The hydrogen bonding improves the initial thermal degradation temperature of fatty acid/wood flour shape stabilized phase change material.(3)Wood flour/phase change wood plastic composite was prepared by introducing fatty acid/wood flour shape stabilized phase change material into wood plastic composite.The results show that when the ratio of fatty acid to wood flour is 1:1,the wood flour/phase change wood plastic composite has no mass loss after heat treatment.The compatibility among the components is good,and the shape stabilized phase change material is tightly encapsulated.The phase change temperature is 21.0 ?,and the latent heat is 32.2 J/g.Components are only physically blended,the chemical property is stable.(4)Fatty acid/polyvinyl chloride microcapsule was prepared with the evaporation temperature of 56 ?,surfactant concentration of 5 %,and shell core ratio of 1:2.Results show that the phase change temperature is 17.1 ?,the latent heat is 92.1 J/g,the encapsulation efficiency is 57.7%.The particle size of microcapsule is micron,there is only physical interaction between shell and core materials.After 500 times of thermal cycles,the change of phase change temperature is less than0.5 ?,and the change of latent heat is less than 2 J/g.The shell material can protect the core material,reduce its thermal degradation rate.(5)Fatty acid/polyvinyl chloride microcapsule was introduced into wood flour/phase change wood plastic composite to further improve its heat storage capacity,and the phase change wood plastic composite was prepared.When the content of microcapsule is 30 %,there is no obvious mass loss after heat treatment.The compatibility between the components of phase change wood plastic composite is good,the shape stabilized phase change material and microcapsule are tightly encapsulated.The phase change temperature is 20.6 ?,the latent heat is 39.1 J/g.There is no chemical reaction between the components,only physical interaction.(6)The simulation results show that the phase change wood plastic composite can realize the "peak shifting and valley filling" power consumption way,which can save electricity.In the process of heat storage and release,the indoor temperature is controlled within the suitable temperature range of human body,and the temperature regulation performance is outstanding.In conclusion,the phase change wood plastic composite prepared in this study shows good energy saving and temperature regulation effect.It has the potential to be applied in the field of building energy conservation.