Thermal Storage Performance Of Polyethylene Glycol And Phase Behavior Of 1-heptanecanol Under Nanocofinement

Phase Change Materials(PCMs)has the ability to change its physical state in a certain temperature range,and the change process of the physical properties is called phase change process.During the process,large amount of latent heat are absorbed or released by the phase change materials.According to the performance of the phase change materials,we can effectively improve the utilization rate of the energy through appropriate design,in order to meet the people's growing demand for energy.Polyethylene glycol(PEG)is a series of polymers with different molecular weights with the melting temperature ranging from 3.2 °C to 68.7 °C.PEG is considered as a promising phase change material for thermal energy storage due to its suitable melting point,high latent heat of the fusion,chemical stability,low-cost,and so on.The 1-heptanecanol is a saturated fatty alcohol with no branched chain,has rich crystalline structure,and may be produced new phase under Nanocofinement.In this study,phase change materials were filled into the porous materials by solution impregnation method to prepare the composites.We studied the thermal storage performance of the system,the main contents of this study are as follows:Based on the solution impregnation method,through the adsorption of porous materials,we prepared the phase change composites of PEG10k/SG,PEG2k/SG,C17OH/SG,C17OH/CPG and C17OH/SBA-15.Study the phase change temperature and the heat of the transition of the phase change materials by using the differential scanning calorimetry(DSC).The experimental results show that the phase transition temperature and enthalpy of the composites are decreased with the decrease of the pore size.Also,the descent range of PEG10k/ SG composite is larger than PEG2k/SG composite.The thermal cycling performance test for 10 times of the composite materials was scanned by using DSC.The results show good thermal stability of the composites.Besides,through study the supercooling of the composites,we know the supercooling increases with the decrease of pore size.Study the characteristic of the composites by using fourier transform infrared spectroscopy(FT-IR),scanning electron microscopy(SEM),X ray diffraction(XRD).The experimental results show that the structure of polyethylene glycol confined in the silica gel pores does not change.This means there is only a simple physical adsorption between the mesoporous materials and filler materials,without chemical changes occurred.