摘要
本文基于严寒C区太阳能光热系统夏季集热器表面温度过高、冬季使用乙二醇工质效率降低的问题,研究团队配制一种适合严寒C区太阳能光热集热器的强化传热、限制基板温度的新型相变流体——乙二醇型相变悬浮微胶囊流体,利用扫描电镜(SEM)、差示扫描量热仪(DSC)、液体导热仪(TC3100L)等仪器对新型相变流体的混合状态、相变潜热和导热系数等物性进行测量,得出物性适合严寒C区太阳能光热集热器的新型相变流体。搭建了基于相变流体的平板式太阳能光热系统实验台,研究测试了集热板表面温度、蓄热水箱温度及系统热效率,探究了不同体积浓度新型相变流体在太阳能光热系统对流换热、限温特性。研究结果表明:在测试工况下,相变材料浓度为5%的新型流体综合导热系数为0.410~0.413 W·m^(-1)·K^(-1),10%浓度为0.381~0.410 W·m^(-1)·K^(-1),均优于防冻液的0.366~0.406 W·m^(-1)·K^(-1),且冰点为-25℃,满足严寒C区太阳能集热器防冻要求。采用5%浓度新型相变流体工质与乙二醇工质两种系统相比,前者集热器基板表面温度降低了3℃,蓄热水箱水温提高了4℃,日均热效率相对升高了21.9%,10%浓度日均热效率相对升高了8.8%,5%浓度相变流体综合性能最佳。
In this paper,based on the problems of high surface temperature of solar thermal collectors in summer and low efficiency of ethylene glycol working medium in winter,the research team prepared a new type of phase transition fluid-ethylene glycol phase transition suspension microcapsule fluid,which is suitable for solar thermal collectors in cold zone C to enhance heat transfer and limit core plate temperature.Using scanning electron microscope(SEM),differential scanning calorimeter(DSC),liquid thermal conductivity meter(TC3100L)and other instruments to measure the mixing state,latent heat and thermal conductivity of the new phase transition fluid,the physical properties of the new phase transition fluid suitable for solar thermal collectors in cold areas were obtained.A flat panel solar photothermal system experiment platform based on phase change fluid was built.The surface temperature of the heat collector plate,the temperature of the heat storage tank and the thermal efficiency of the system were studied.The convective heat transfer and temperature limiting characteristics of the new phase change fluid with different volume concentrations in the solar photothermal system were studied.The results show that:Under the test condition,the comprehensive thermal conductivity of the new fluid with 5%phase change material concentration is0.410~0.413 W·m^(-1)·K^(-1),10%concentration is 0.381~0.410 W·m^(-1)·K^(-1),which is better than that of the antifreeze 0.366~0.406 W·m^(-1)·K^(-1),and the freezing point is-25℃.It meets the anti-freezing requirements of solar collector in cold zone C.The surface temperature of the collector substrate is decreased by 3℃,the water temperature of the storage tank is increased by 4℃,the average daily thermal efficiency is increased by 21.9%,and the average daily thermal efficiency is increased by8.8%at 10%concentration.The 5%concentration phase change fluid has the best comprehensive performance.
作者
齐典伟
张佳琦
徐凤
饶博闻
李亚菲
QI Dianwei;ZHANG Jiaqi;XU Feng;RAO Bowen;LI Yafei(School of Civil Engineering and Architecture,Xinjiang University,Urumqi 830046,China;School of Mechanical and Energy,Tongji University,Jiading District,Shanghai 201800,China)
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2023年第1期183-190,共8页
Journal of Engineering Thermophysics
基金
2022年新疆维吾尔自治区自然科学基金(No.2022D01C413)。
关键词
太阳能集热系统
新型相变流体
导热系数
对流换热
热效率
solar heat collecting system
new phase change fluid
Thermal conductivity
convective heat transfer
thermal efficiency
