Study On The Functionalization Of Phase Change Materials And The Phase Change Energy Storage Equipment

The energy crisis is the key problem that restricts the development and progress of human civilization,so the research and development of advanced energy materials have always been the hot topic.As a kind of advanced energy materials,phase change materials have gained the wide attention.Phase change materials have a constant phase transition temperature in phase transformation process,which can absorb or release a lot of heat.They have greater energy density than traditionally sensible heat storage materials,and the storage and release of energy are completely reversible,so they are the ideal thermal storage materials.However,the problem of liquid phase fluidity of phase change materials seriously restricts their applications.Therefore,encapsulated phase change materials are developing rapidly.Microencapsulated phase change materials?MicroPCMs?are typical encapsulated phase change materials.Although the encapsulated phase change materials can be applied on some fields,the functional phase change materials have been not grown up.The functionalization of phase change materials will have some other properties,such as photocatalysis,magnetization and so on,besides the properties of phase change materials.The main contents of this paper are the preparation and characterization of magnetic microencapsulated phase change materials,and the design of variable temperature and constant temperature energy storage equipment based on phase change materials.1.The magnetic phase change material is an important direction of the functional phase change materials.A series of magnetic MicroPCMs samples are synthesized by polymerization and coprecipitation method and the chemical composition contained Fe₃O₄ modified poly?MMA-MAA?@n-octadecane.And they were characterized by SEM for microscopic morphology,FTIR for chemical structure,XRD for crystalline structure,DSC for phase change behaviors,TGA for thermal stability,and PPMS for magnetic properties.After these characterization,the magnetic MicroPCMs exhibited excellent magnetic and phase change properties.For example,the 11 percent of content of Fe₃O₄ in the magnetic MicroPCMs still presented 20 emu·g^-1 saturation magnetization with 132 J·g^-1 enthalpy.The results fully illustrate that the magnetic MicroPCMs fulfill both application on thermal energy storage and magnetic control.2.The design of the variable temperature and phase change constant temperature energy storage equipment breaks through the traditional fixed phase change energy storage equipment and changes the output temperature without changing the phase change materials to adapt to different temperature requirements.Through the test in this paper,two conclusions are obtained:1)Different target temperature can both reach constant temperature with same phase change materials.The higher target temperature,the longer time to keep constant temperature when the heating power is same.The lower heating power,the longer time to keep constant temperature when target temperature is same.2)The device would be cooled after removing the heating power,and then the equipment can release thermal energy from the phase change materials and heat the device for a period of time.It is proved that the equipment can still keep the constant temperature at different temperatures without changing the phase change materials.