金属直通型集热管非选择性吸收涂层段热性能研究

Study on Thermal Performance of Non-Selective Absorption Coating Part for Metal Straight-Through Receiver

考虑金属连接裸管和膨胀节的影响,建立了太阳能槽式集热器能量转换数学模型,分析其吸热、散热和光热转换效率并与常规计算方式进行了对比。计算表明金属连接裸管段的热损失较大,其对集热器性能的影响较膨胀节更为显著。随着太阳直射辐射强度的降低和金属集热管温度的升高,太阳能槽式集热器光热转换效率逐渐降低。对比等同计算方式,本文所采用的差异化计算所得的吸热量较低,集热器热效率与文献中的实测值相比误差在3%左右,更加贴近实际情况。

In this paper, a mathematical model of a parabolic trough collector is presented by considering the impacts of the bare sections of metal connecting pipe and expansion joints. The heat absorbed, heat loss and thermal efficiency of the collector are analyzed and compared with that of from conventional methods. The calculation shows that the heat loss of the bare sections of metal connecting pipe is relatively higher, which has a more obvious effect than the expansion joints on collector performance. With the intensity of beam solar irradiation decreasing, and the temperature of metal collector tube increasing, the thermal efficiency of the collector decreases. Compared with the equivalent calculation way, the differentiated calculation method provides more accurate results, and the bias error against the measured data in the literature is about 3%.