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Summary: Composite expended graphite (EG)/Ba(OH)2·8H2O form‐stable phase change material (PCM) is prepared with porous adsorption method in this study to solve the problem of the leakage risk in the application process based on barium hydroxide octahydrate. In addition, the thermal properties and stability have been measured and verified. Thermal conductivity of each group composite material was enhanced by about two to four times, while the addition has little negative effect on the other properties. With microscopic features being characterized by scanning electron microscope (SEM), the experimental result demonstrates that the composite material with 7 wt% of EG is optimal to be a saturated state between two phases. After the thermal cyclings of 100, 300, and 500 times, thermal properties did not change dramatically, which can be used as an ideal material for solar thermal storage system within finite thermal cyclings. In order to simulate the operating condition of solar energy or waste heat storage, the composite material was encapsulated in the heat storage unit with pipe bundle, and heat storage/release experiences were performed to test the performance of the material and hot water supply. The results indicate that the composite material is qualified to storage and release sufficient heat. The experimental data can provide necessary technical reference for engineering design and effect prediction in practical application. [ABSTRACT FROM AUTHOR]

With the rapid increase of the thermal power of electronic devices, phase change material(PCM) have shown great application prospects in the field of electronic thermal management. However, due to the irregular surface of the electronic device, PCM can only act on the back of the component or the outside of the package, which leads to the occurrence of heat transfer hysteresis. In order to reduce the heat transfer distance between the heat source and PCM, a new type of ER/SAT/DSP composite functional material with thermal control function was prepared in this paper to solve the key technical problem of fluid seamless packaging thermal control. The composite material is encapsulated in a fluid state and will no longer melt after solidification. Through thermophysical experiments and morphological characterization, the results show that when the mass fraction of PCM is 35%, the composite material has the best physical properties and application performance. And after 200 thermal cycles, the leakage rate is only 3.7%. Through the PTC thermal control experiment, the results show that the maximum temperature at different positions of the device for pouring the new composite was reduced by 7.4 °C and 8.1 °C, respectively, and the operation time corresponding to different temperatures was increased by 5.76 times, 5.80 times and 6.98 times, respectively. Therefore, the composite material shows a good thermal control ability for electronic components of any surface shape. [ABSTRACT FROM AUTHOR]