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采用某国产直通式太阳集热管(中温集热系统核心部件),搭建435 m~2微弧菲涅尔聚光集热系统。建立该集热管一维稳态传热模型;分析热损失随真空度、金属管内壁与环境的温差和风速的变化规律;考察太阳辐照度、聚光比以及导热油流量对集热效率的影响;对集热效率进行实验测试。结果表明:模型计算值和实验值偏差小于2%,可用于传热性能预测。真空度和温差是影响热损失的主要因素,应保持气体压力小于0.013 Pa;通过非线性回归建立温差和热损失的关系式。聚光比为25,太阳直接辐照度为625 W/m~2时,集热效率达到55.4%;合适的操作流量为3.5 m~3/h。集热温度低于200℃时,该集热管的集热性能与UVAC3相当,可用于太阳能中温热利用领域。
Adopting a domestic straight-through solar collector tube (the core part of the temperature collector system), a 435 m ~ 2 micro-Fresnel condenser system is set up. The one-dimensional steady-state heat transfer model of the collector was established. The variation of heat loss with the degree of vacuum, the temperature difference between the inner wall of the metal tube and the environment and the wind speed were analyzed. The influence of solar irradiance, condenser ratio and heat transfer oil flow on collector efficiency was investigated The experiment of heat collection efficiency was carried out. The results show that the deviation between the calculated value and the experimental value is less than 2%, which can be used to predict the heat transfer performance. Vacuum and temperature difference are the main factors that affect the heat loss. The gas pressure should be kept at less than 0.013 Pa. The relationship between temperature difference and heat loss should be established by nonlinear regression. Concentration ratio of 25, the direct solar irradiance of 625 W / m ~ 2, the heat collection efficiency of 55.4%; the appropriate operating flow of 3.5 m ~ 3 / h. When the collector temperature is lower than 200 ° C, the heat collecting tube has the same heat collecting performance as UVAC3, and can be used in the field of solar thermal energy utilization.