低温相变蓄冷材料热物性的高精度预测模型

Highly Accurate Prediction Models for Thermophysical Properties of PCMs

针对实验法研究低温蓄冷材料性能耗时长、误差大、低温实验条件苛刻等问题,提出了基于SRK-UNIFAC方程计算液相逸度,采用虚拟路径参考态法求取固相逸度的热力学方法来模拟研究低温相变蓄冷材料.利用改进的方法预测复合低温固液相变材料的共晶点、共晶配比及熔化焓等热物性质,结果表明,新方法的准确度较高,与实验法的精度误差小.以液化天然气(LNG)冷能空分装置为例,通过建立的高精度模型预测相变材料热物性可有效地进行蓄冷装置的选材及应用.

Aiming at the limitations of experimental study on thermophysical properties of cryogenic PCMs,such as long duration,big deviation and harsh cold condition test,a highly accurate method to predict solid-liquid equilibrium(SLE) of PCMs,where SRK-UNIFAC model is used in the fugacity of PCMs in liquid phase and method of referenced state by hypothetic path is used in solid phase,was proposed.Based on the improved method,the thermophysical properties of composite cryogenic PCMs including eutectic composition,eutectic temperature and eutectic enthalpy were accurately predicted with a minor deviation.Furthermore,taking the LNG air separation unit as an example,the established simulating method with high accuracy to predict PCMs’ thermophysical properties was adopted for material selection and adaptive application for cryogenic energy storage unit in this project with high efficiency.