Department of Materials Science and Physical Chemistry, Universitat de Barcelona, Martí i Franqués 1, 08028 Barcelona, Spain.
Departament de Química Inorgànica i Orgànica, Secció de Química Orgànica, Universitat de Barcelona, Martí i Franqués 1, 08028 Barcelona, Spain.
Molecules. 2021 Feb 12;26(4):982. doi: 10.3390/molecules26040982.
The use of adequate thermal energy storage (TES) systems is an efficient way to achieve thermal comfort in buildings reducing the cooling and heating demand. Besides, deploy phase change materials (PCM) to meet and enhance the TES needs is highly effective and widely studied. In this paper, a study of the degradation of two fatty acids is presented, capric and myristic acids, in order to evaluate whether their thermo-physical properties are affected throughout time during service. This was carried out by means of two different types of thermal treatments: degradation at constant temperature (thermal stability test), 60 °C during 100 h and 500 h, and degradation with heating and cooling cycling (thermal cycling stability), between a temperature range from 15 °C to 70 °C with 0.5 °C/min ramp during 500 and 1000 cycles. Despite no significant changes were measured for myristic acid, experimental results revealed a decrease of melting enthalpy of 6.6% in capric acid thermally treated for 500 h. Evidences of chemical degradation were found that might explain the decrease in thermophysical properties during use.
使用足够的热能储存（TES）系统是在建筑物中实现热舒适、减少冷却和加热需求的有效方法。此外，部署相变材料（PCM）来满足和增强 TES 的需求是非常有效的，并且得到了广泛的研究。本文研究了两种脂肪酸，即癸酸和肉豆蔻酸的降解情况，以评估它们的热物理性能在使用过程中是否会随时间而变化。这是通过两种不同类型的热处理来实现的：恒温下的降解（热稳定性测试），在 60°C 下进行 100 小时和 500 小时；以及加热和冷却循环下的降解（热循环稳定性），在 15°C 至 70°C 的温度范围内，以 0.5°C/min 的斜坡速率进行 500 次和 1000 次循环。尽管肉豆蔻酸没有测量到明显的变化，但实验结果显示，经过 500 小时热处理的癸酸的熔融焓下降了 6.6%。发现了化学降解的证据，这可能解释了在使用过程中热物理性能的下降。
