Research On Preparation And Performance Of Paraffin/High Polymer/Metal Copper Form-Stable Thermal Energy Storage Materials

With the rapid development of economy and society, human’s demand for energy has increased sharply. Adding the global warming problem, energy conservation,emissions reduction and improve energy efficiency have become the issues we have to face up. Heat storage technology has been used in many fields such as waste heat recovery, solar thermal power generation and electronics thermal protection to balance the mismatches of energy use in space and time, thus reducing energy consumption and increasing energy efficiency.Paraffin has been widely applied to the phase change heat storage system, because of its high energy storage density, no super cooling, and cheap price etc. But the low thermal conductivity and paraffin leakage when phase change restricts the application of paraffin wax in a certain extent. One of the important ways to solve this problems is to prepare form-stable phase change materials.This paper studied two kinds of systems with high density polyethylene(HDPE) and SEBS as support materials, prepared paraffin/HDPE and paraffin/SEBS form-stable phase change materials by melting blend method and direct impregnation method respectively and compared their form-stable performances after several thermal cycles. Leakage test revealed that the high density polyethylene can keep paraffin form-stable to some extent. Some paraffin leaked because of the pore formed by high density polyethylene(HDPE) is not small enough and the density change of paraffin is bigger than that of HDPE. The network structure of SEBS can keep paraffin form leakage and paraffin/SEBS composite is powder like after preparation.Combining the advantages of HDPE and SEBS as supporting materials, paraffin/SEBS/HDPE form-stable phase change materials were prepared by blending paraffin/SEBS composite with melted HDPE. Thermal properties were analyzed by using scanning electron microscope(SEM), differential scanning calorimeter(DSC), Fourier infrared spectrum analyzer(FT IR) X-ray diffraction analysis(XRD) and thermal constant Hot Disk analyzer and the composites’ heat stability was tested by thermal cycles. The results showed that paraffin had spread in the network of SEBS uniformly and paraffin, SEBS, HPDE has good chemical compatibility. The phase change temperature and heat latent of paraffin/SEBS/HDPE is 50.56 °C and 151.6 J/g respectively. And the optimum ratio of three component is 6:1:0.5. The thermal conductivity of Paraffin/SEBS/HDPE was 0.272 W/m?K. In order to overcome the problem of low thermal conductivity, the Paraffin/SEBS/HDPE composites were injected into copper foam when the composites melt into a gel at 120 °C. Compared with paraffin/SEBS/HDPE, the thermal conductivity was increased up to 2.142 W/m?K when copper foam was embedded in the composite, indicating that copper foam can effectively improve the thermal conductivity of the composite.