Organic phase-change material for enhanced energy storage was prepared by adding SiO2 particles in a certain proportion into molten palmitic acid (PA) with stirring and intensive sonication at a constant temperature. The thermal properties of the SiO2/PA composite were experimentally characterized. As compared with the pure PA, the latent heat capacity of the composite with addition of 3 wt% SiO2 particles is increased by 51.7 kJ/kg, reaching 214.7 kJ/kg, which is the highest value among the composites tested with varying SiO2 ratio from 1 to 5 wt%; the thermal conductivity of the 3 wt% SiO2/PA composite is also increased by 12% at 30 oC (solid state) and 7% at 70 oC (liquid state), respectively. A water heater was built and tested with embedded capsules containing the 3 wt% SiO2/PA composite and pure PA, respectively. The lab-built phase-change water heater is much smaller in size than an ordinary household water heater in comparison and uses reduced electrical power. However, it responds faster and has a larger volume ratio of hot water output to water heater size. During the 2 turning-off test, the water heater with 3 wt% SiO2/PA can provide 2.23 times hot water of heater size; while the ordinary water heater can only provide 1.41 times hot water volume of tank size.

中文翻译：

---

使用有机相变材料增强热水器的能量储存：一项实验研究

将一定比例的SiO2颗粒加入熔融的棕榈酸（PA）中，搅拌并在恒温下进行强声波处理，制备了用于增强储能的有机相变材料。实验表征了 SiO2/PA 复合材料的热性能。与纯 PA 相比，添加 3 wt% SiO2 颗粒的复合材料的潜热容量增加了 51.7 kJ/kg，达到 214.7 kJ/kg，这是在不同 SiO2 比例下测试的复合材料中的最高值。 1至5重量％；3 wt% SiO2/PA 复合材料的热导率在 30 oC（固态）和 70 oC（液态）时也分别增加了 12% 和 7%。建造了一个热水器，并用分别含有 3 wt% SiO2/PA 复合材料和纯 PA 的嵌入胶囊进行了测试。与普通家用热水器相比，实验室制造的相变热水器的尺寸要小得多，并且使用的电能也更少。但是，它的响应速度更快，热水输出量与热水器尺寸的体积比更大。在第2次关机测试中，含3wt%SiO2/PA的热水器可提供热水器尺寸的2.23倍；而普通热水器只能提供水箱大小的1.41倍热水量。