兰州地区日光温室用双管多曲面槽式空气集热器结构优化及其应用

以双管多曲面槽式空气集热器为试验对象,采用蒙特卡罗光线追踪法对不同结构参数的集热器进行光线追踪,结合信噪比分析得到较优结构的集热器,以期达到最大的光线汇聚率,并与兰州地区的日光温室太阳能主被动协同蓄热供热墙体相结合构成主动集热系统,考查其应用效果。结果表明:当集热器在进光口宽度为670 mm,出光口宽度为210 mm,集热器总高度为545 mm,二次反射平面镜高度为40 mm时,光线汇聚率在太阳入射角为0°~7°时可达到100%。工程试验结果显示,若日累计太阳辐射强度为19 MJ·m-2,室外平均环境温度为1.8℃时,总长10 m且管内空气流速为1.67 m·s-1的集热系统可获得2115 W的瞬时集热量和35.7%的最大瞬时集热效率。并统计出该集热系统在冬季晴天实测的28 d里累计集热量为633 MJ。该研究结果可为双管多曲面槽式空气集热器优化设计及其实际应用提供参考依据。

The Structural Optimization and Its Application of the Double-tube Multi-curved Trough Air Collector for Solar Greenhouse in Lanzhou

In order to achieve the maximum light convergence rate of the double-tube multi-curved trough air collector,the Monte Carlo ray tracing method was used to ray trace the collectors with different structural parameters,and the signal-to-noise ratio analysis was also used to obtain the optimal structured collector,meanwhile,its heat collecting performances combined with the solar energy active-passive heat storage heating wall of the solar greenhouse in Lanzhou to form an active heat collecting system were examined.The results showed that when the width of the light collector was 670 mm,the width of the light outlet was 210 mm,the total height of the collector was 545 mm,and the height of the secondary reflecting plane mirror was 40 mm,the heat source convergence rate of the double-tube multi-curved trough air collector could reach 100%at the solar incident angle of 0°to 7°.The engineering test results showed that if the cumulative solar radiation intensity was 19 MJ·m-2 and its average outdoor temperature was 1.8℃,the collector system with the total length of 10 m and the air velocity of 1.67 m·s-1 in the double tube could obtain 2115 W for the instantaneous heat collection capacity,and the instantaneous heat collection efficiency was 35.7%,and it was calculated that the accumulated heat collected by the heat collection system in 28 days of winter sunny days was 633 MJ.The results could provide a reference for the optimal design of double-tube multi-curved trough air collector and its practical application.