Study On Preparation And Performance Of New Phase Change Materials Suitable For Thermal Insulation Of Carriages

In the 21 st century,when China entered the era of high-speed air-conditioned trains,the speed of trains continued to increase,and people's requirements for train passenger transport conditions were also getting higher and higher.Modern passenger vehicles not only need to meet the requirements of high-speed operation,but also provide comfortable and hygienic conditions for passengers.Train body tightness and heat insulation are important factors affecting the thermal load of the vehicle body.Increasing the thermal insulation performance of the enclosure structure can not only reduce the mechanical energy consumption of the air conditioning system,but also provide passengers with a more comfortable ride environment.The materials used in the envelope structure directly affect the thermal insulation performance of the vehicle body.As a new type of energy storage material,the phase change material can store and release a large amount of heat in the same volume as other materials and use it for the envelope structure.The heat insulation can reduce the thickness of the heat insulation layer,increase the space for activities in the vehicle,and at the same time reduce the energy consumption of mechanical cooling to achieve the purpose of energy saving and environmental protection.Polyethylene glycol(PEG)is an excellent polymer phase change material,which has the advantages of non-toxicity,high latent heat of phase change,stable performance,corrosion resistance,etc.However,the biggest problem is that it is easy to leak.Therefore,this paper adopts physical sharing.Therefore,to solve the problem of easy leakage of polyethylene glycol,two new types of PEG/TAMS and PEG/Meso-Onion-S composite phase change materials were prepared by physical blending and vacuum impregnation,respectively.The composition structure,thermal stability,crystallization performance and chemical properties of the composite material were studied by various testing methods.A novel shape-stabilized phase change material(PEG/TAMS),fabricated using tannic acid-templated mesoporous silica(TAMS)as a support for polyethylene glycol,was developed for thermal energy storage.The method used to synthesize TAMS was simple,cost effective,environmentally friendly and free of surfactant.The characterization resultsindicated that PEG was physically absorbed to TAMS,and TAMS had no influence on the crystal structure of PEG.According to the TGA thermograms,PEG/TAMS has excellent thermal stability and can be applied over a wide temperature range.Additionally,the DSC results suggested that PEG/TAMS has good thermal properties,and its fusion and solidification enthalpies reached 114.7 J/g and 102.4 J/g,respectively.The results indicated that PEG/TAMS has great potential for practical applications.A novel shape-stabilized phase change material(PEG/Meso-Onion-S)was synthesized using onion-like silica(Meso-Onion-S)as the matrix of polyethylene glycol(PEG).The characterization and thermal energy storage properties of PEG/Meso-Onion-S were studied.The characterization results indicated that the interaction between the PEG and Meso-Onion-S was physical adsorption,and the Meso-Onion-S had no influence on the crystal structure of PEG.Results of thermogravimetric analysis showed that the PEG/Meso-Onion-S had a good thermal stability,and no apparent weight loss was observed from 30 ? to 250 ?.The DSC results indicated that the fusion and solidification enthalpies of the PEG/Meso-Onion-S could reach 120.4 J/g and 108.56 J/g,respectively.All the results suggested that the PEG/Meso-Onion-S has immense potential for practical applications.The new stereotyped composite phase change material was applied to the heat insulation wall,and the phase change material can absorb the excess heat in the air and release it when needed.Therefore,it can lower the heat transfer temperature difference,reduce the thickness of the heat insulation layer,increase the net volume of the vehicle body,reduce the mechanical energy consumption,and prolong the cooling The life of the equipment to achieve the effect of energy saving.