Preparation And Temperature Regulation Properties Of Photo/Electric Driven Phase Change Material

The use of phase change materials（PCMs）for thermal energy storage（TES）can solve the imbalance between energy supply and demand in time and space,and improve energy efficiency.Traditional solid-liquid PCMs have the advantages of high energy storage density and abundant raw materials.However,the traditional solid-liquid PCMs are faced with the problems of liquid leakage and only relying on thermal energy.The applications of PCMs in energy conversion and storage are limited.Therefore,the preparation of form-stable PCMs with multi-energy driving performance is one of the research hotspots at present.Graphene’s photo-thermal conversion property and electrical conductivity make it an ideal multi-drive filler,and a simple method can be used to produce a three-dimensional reduced graphene oxide aerogel（r GOA）,which can both prevent leakage of molten PCMs and introduce multi-drive properties.In addition,the low density of r GOA can effectively avoid the latent heat decrease caused by the excessive proportion of matrix in the composite PCMs.Therefore,r GOA can be used to prepare the form-stble PCMs with multi-energy driving characteristics.As a rigid support matrix,r GOA can provide good structural support for composite PCMs.However,it is not conducive to the installation of complex shape equipment for temperature regulation,which limits the application range of composite PCMs.Therefore,flexible composite PCMs should be prepared for flexible selection according to requirements.This thesis uses the hydrogenated styrene butadiene block copolymer（SEBS）,which has good compatibility with paraffin wax（PW）,to reduce the fluidity of PW in the molten state.And SEBS cooperation with the r GOA to construct a form-stable PCMs.By changing the ratio of SEBS and PW to explore the balance between the enhancement of form-stable and the reduction of latent heat.A series of performance analysis shows that the PW/SEBS/r GOA has both leakproof and high latent heat when SEBS accounts for 5 wt%of PW,and also has good thermal reliability.In addition,PW/SEBS₅/r GOA can change phase under the direct drive of light energy and electric energy,and has the ability to convert light energy and electric energy into heat energy and store it as latent heat.In addition,due to the photo-thermal performance and electrical conductivity of r GOA,PW/SEBS₅/r GOA has the ability to convert light energy and electric energy into heat energy and store them in the form of latent heat.In order to prepare flexible composite PCMs,sodium dodecyl sulfate（SDS）was introduced as the microbubble template,and natural latex was added to increase the flexibility and elasticity of r GO matrix wall.A flexible reduced graphene oxide matrix（LGA）with flexible bending ability and easy macroscopic morphology was prepared.PW/SEBS₅/LGA exhibits thermal flexibility at temperature higher than PW melting point due to the flexible characteristics of LGA.Further,the thermal properties of PW/SEBS₅/LGA were characterized.The latent heat of PW/SEBS₅/LGA was 215 J/g,and which only decreased 2.8%after 200 accelerated thermal cycles.The introduction of natural latex particles improves the light energy absorption of the aerogel.Therefore,PW/SEBS₅/LGA has a good thermal storage capacity driven by light energy.However,the electrical conductivity of the aerogel is reduced,which makes the electro-thermal conversion and storage capacity of PW/SEBS₅/LGA slightly weaker than that of PW/SEBS₅/r GOA.Based on the advantages of easy control of macromorphology during the preparation process of LGA,PW/SEBS₅/LGA was selected for subsequent experiments to explore the heat storage and release law and temperature regulation characteristics of PW/SEBS₅/LGA driven by light and electric energy.In addition,whether the phase change process is driven by light energy or electric energy,the air temperature can be further regulated without affecting the material heat storage only by starting convection in the exothermic stage.