Study On Preparation And Thermal Properties Of Composite Phase Change Materials With Sio2 Skeleton

With the energy crisis increasing, development and application of new energy sources and energy saving technologies have received more attention, which include phase change energy storage technology. Phase change energy storage technology is that phase change materials absorb and release heat during phase transformation process,attain the purpose of energy-storage and energy-release, and solve the contradiction of energy application and time-space, achieve the purposes of fully utilizing and improvement of energy utilization ratio, to wide application prospects in building construction, solar energy, waste heat recovery and so on. According to the problems of volume change and liquid leakage of organic phase change materials during phase transformation process, put forward the solution that organic phase materials compound with silicon dioxide materials to prepare composite phase change materials.Lauric acid was imbedded into the net of silicon dioxide (SiO2) to preparing lauric /silicon dioxide phase change energy storage composite material by sol-gel method in the research, lauric acid as phase change materials and silicon dioxide as matrix materials. The structure, morphology, and thermal performance of the composite were characterized by IR, SEM and DSC. The results show that the composite phase change materials containing 69.1%(mass fraction) lauric acid has a melting temperature of 43.1℃and latent heat of 104.64J/g. Lauric acid is uniformly imbedded into the net of silicon dioxide without melted leakage from the composite frame. The thermal conductivity of the phase change material can be improved effectively by using silicon dioxide as a supporting material.Lauric /silicon dioxide phase change energy storage composite materials were prepared by low heating solid state reaction, lauric acid as phase change body materials and sodium silicate as raw materials. The structure, morphology, and thermal performance of the composite were characterized by IR, ESEM, DSC, XRD, etc. As the results, lauric acid materials are imbedded effectively when the mass ratio of sodium silicate and lauric acid materials is 2:5. The latent heat and melting temperature of the composite is 98.94 J/g and 58.6℃respectively. The thermal conductivity of composite phase change materials is improved by using silicon dioxide as coating materials.paraffin/silicon dioxide composite microcapsule materials were prepared by emulsion method using paraffin as phase body materials, TEOS as silicon raw materials, silicon dioxide imbedded paraffin microspheres by hydrolysis and polycondensation of TEOS in acid environment. The structure, morphology, and thermal performance of the composite were characterized by IR, ESEM, DSC, XRD, et al. As the results, the TEOS can hydrolyze and polycondensate on the surface of paraffin microspheres. The average diameter of composite microcapsules is 50μm approximately, and latent heat of composite microcapsules is 110.4 J/g, and malting temperature is 50.1℃.The composite phase change materials have high latent value and well thermal conductivity, and low phase transformation temperature, which can be used to room temperature energy storage and energy regeneration system.