国产直通式太阳集热管性能研究

PERFORMANCE OF A DOMESTIC STRAIGHT-THROUGH TYPE SOLAR RECEIVER

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。

A 435 ms micro-arc Fresnel concentrating solar collector pilot installation integrating the domestic straight- through type receiver（STR）, which was the key component of moderate temperature heat collecting system, was set up. A one dimensional steady-state heat transfer model of the receiver was developed. Based on this model, the influences of vacuum level, temperature difference between the metal absorber and ambient as well as wind speed on heat loss were analyzed. The effects of solar irradiance, concentration ratio and flow rate of the heat transfer oil on the thermal efficiency of this pilot installation were investigated. Also, the thermal efficiency was measured that, the heat transfer model could well describe and predict the characteristics of the experimentally. The results showed STR with a lower than 2% relative error of the calculated results compared with the experimental data. Vacuum level and the temperature difference are the major factors that influence the heat loss, and the annulus pressure should be kept lower than 0.013 Pa. A correlation was developed to predict the heat loss as a function of the temperature difference efficiency reaches 55.4% with a concentration ratio of 25 at 625 W/m2 direct through nonlinear regression. The thermal solar irradiance. The optimized flow rate is 3.5 m3/h. The domestic STR, which has the heat collecting performance similar to the UVAC3 during the temperature lower than 200 ℃, is perspective for the moderate temperature solar heat applications.