太阳能槽式系统接收器光学效率的特性研究

Study on Optical Efficiency Characteristics of Receivers in a Solar Parabolic Trough Concentrator

从理论上分析了真空管和三角形腔体两种接收器之间的光学效率差异，给出了腔体接收器有效吸收率取优化值时临界安装位置的计算表达式，并基于TraeePro软件进行了模拟计算验证。模拟结果显示腔体光学效率可达89．1％，而真空管为77．1％，垂直和平行方向安装位置的偏差对两者效率的影响类似，但腔体接收器光学效率变化曲线呈现轻微的不对称性，垂直安装位置取焦距下方5—20mm范围内最佳。反射镜面偏转误差对接收器效率的影响较大，偏转角度应控制在0．4。以内，超出该角度时腔体效率下降的幅度小于真空管。实验测试结果证实了这一结论，并且推算出在理想安装条件下、集热温度为168．6℃时两者集热效率达到平衡点55．0％，低于该临界温度时腔体接收器更占优势。

Optical efficiency differences between the evacuated tube receiver and a triangular cavity receiver are theoretically analyzed. Furthermore, the calculation expressions of the critical installation position for the optimal effective absorptivity of the cavity receiver are given, which is validated through TracePro software simulation. Simulation results show that the optical efficiency of cavity receiver can reach 89.196, while the evacuated tube＇ s efficiency is 77.196. Meanwhile, the installation position deviations in the vertical or parallel direction have similar impacts on efflciencies of both receivers, but the cavity＇s efficiency curve is slightly asymmetrical, which indicates that the best vertical installation position is 5-20 mm below focal length. It is also observed that mirror deflection error has greater influence on receiver efficiency, and the deflection angle should be controlled within 0.4~. Beyond this range, the descend degree of cavity receiver efficiency is less than the evacuated tube, which is confLrmed by experimental test results. In addition, the thermal efficiencies of both receivers would meet at equilibrium point of 55.096, in the case of ideal installation condition and heat collecting temperature of 168.6℃. Below this critical temperature, cavity receiver has a higher efficiency.