辛酸/月桂酸作为相变蓄冷材料的热性能研究

THERMAL PROPERTIES OF CAPRYLIC ACID AND LAURIC ACID AS PHASE CHANGE COOL STORAGE MATERIAL

利用差示扫描量热法和低温显微技术研究辛酸、月桂酸及其二元系统的热性能,建立辛酸/月桂酸二元系统相图。实验结果表明:辛酸/月桂酸二元系统的相图较复杂,辛酸质量分数较低时发生转熔,转熔温度约为14℃,转熔点相应的辛酸质量分数为60%;辛酸质量分数较高时发生共晶,共晶熔融温度为7.44℃,相变潜热为136.43J/g,共晶点相应的辛酸质量分数为80%,该共晶熔融温度适合于空调蓄冷。辛酸/月桂酸共晶混合物经过60次、120次冻熔循环后,其共晶熔融温度、熔融热、比热未发生明显变化,具有较好的热稳定性,可用作相变蓄冷材料。

Differential scanning calorimetry （DSC） and cryomicroscope were used to investigate the thermal proper- ties of caprylic acid, lauric acid and their binary system, and the phase diagram was obtained. The experimental results showed that the phase diagram of caprylic acid/lauric acid binary system is complex. Peritectic occurs in the low concentration range of caprylic acid. The periteetic temperature is about 14℃, and the corresponding mass fraction of caprylic acid in peritectic point is 60%. Eutectic occurs in the high concentration range of caprylic acid. The eutectic melting temperature is 7.44℃, and the latent heat is 136.43J/g. The corresponding mass fraction of caprylic acid in eutectic mixture is 80%. The eutectic melting temperature is suitable for air-conditioning cool stor- age. The eutectic melting temperature, the latent heat of phase change and the specific heat of eutectic mixture have not obvious variations after 60 and 120 thermal cycles, which proves that the eutectic mixture has good thermal stability. Therefore, it can be used as phase change cool storage material.