Preparation and characterization of nano-sized phase change emulsions as thermal energy storage and transport media
Preparation and characterization of nano-sized phase change emulsions as thermal energy storage and transport media
复制标题
热能储存和传输介质纳米相变乳液的制备与表征
DOI：
10.1016/j.apenergy.2017.01.012
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发表时间：
2017-03-15
期刊：
影响因子：
11.2
通讯作者：
Zhang, P.
中科院分区：
文献类型：
--
作者：
Chen, J.;Zhang, P.
相变乳化液（PCE）是一种相变材料（PCM）分散在载液中的两相传热流体。近年来，由于它可以同时用作热能存储系统中的热能存储材料和传输介质，因此它受到了强烈的吸引力。本文以正十六烷和正十八烷为相变材料，采用D相法制备了纳米级的相变材料。的热物理和传输性能的特点，以促进应用。用光子相关光谱仪测量了PCE的液滴粒径分布，结果表明，不同质量分数下的液滴粒径分布相似。用流变仪测定了PCE的流变行为和粘度，结果表明质量分数低于30.0wt%的PCE为牛顿流体，其粘度与质量分数和温度有关。采用差示扫描量热法（DSC）对PCE的相变特性进行了分析，结果表明水和PCM在PCE中存在较大的过冷度。PCE中水的熔化温度和潜热远小于纯水。采用瞬态热线法测量了不同温度下不同质量分数四氯乙烯的导热系数。此外，能量传输特性的PCE的基础上，测量的热物理和传输性能进行评估。结果表明，与水相比，在相同的热存储容量的PCE的泵送功率急剧减少。(C)2017爱思唯尔有限公司版权所有
Phase change emulsion (PCE) is a kind of two-phase heat transfer fluid with phase change material (PCM) dispersed in carrier fluid. It has received intensive attractions in recent years due to the fact that it can be used as both the thermal energy storage material and transport medium simultaneously in a thermal energy storage system. In the present study, nano-sized PCEs are prepared by the D-phase method with n-hexadecane and n-octadecane as PCMs. The thermo-physical and transport properties are characterized to facilitate the applications. The droplet size distribution of the PCE is measured by a Photon Correlation Spectroscopy, and the results show that the droplet size distributions are similar at different mass fractions. The rheological behavior and viscosity of the PCE are measured by a rheometer, which shows that the PCEs at mass fractions below 30.0 wt% are Newtonian fluids, and the viscosities are dependent on both the mass fraction and temperature. The differential scanning calorimetry (DSC) is employed to analyze the phase change characteristics of the PCE, and the results indicate large supercooling degree of water and PCM in the PCE. The melting temperature and latent-heat of water in the PCE are much smaller than those of pure water. The thermal conductivities of the PCE with different mass fractions at different temperatures are measured by the transient hot-wire method. Furthermore, the energy transport characteristics of the PCEs are evaluated on the basis of the measured thermo-physical and transport properties. The results suggest that the PCEs show a drastic reduction of pumping power compared with water at the same heat storage capacity. (C) 2017 Elsevier Ltd. All rights reserved.