基于槽式太阳能系统的镜面积尘的影响及预测方法分析

Effect and Prediction Method of Specular Dust Based on Trough Solar System

基于双轴跟踪槽式太阳能系统对比实验平台,通过理论分析和实验测试的方法研究了积尘对槽式太阳能系统光热性能的影响。引入积尘反射因子和采集因子修正系数来量化积尘对系统光热性能的影响程度。研究结果表明聚光器镜面积尘对焦面聚光特性有明显影响,积尘分布的不均匀性造成散射辐射较为严重,随着积尘量的增加,一定尺寸内的焦面获得的能量减少,焦面中心能流密度减小,小尺寸开口接收器对焦面可采集能量的变化更为敏感。若要保证实验中的槽式聚光镜采集因子修正系数大于0.90,积尘反射因子需小于4.3%;建立了一种积尘对槽式太阳能系统集热性能影响的预测模型,通过实验测试进行了验证,该模型预测值与实验值的相对误差小于5.07%,两者的吻合度较高。该预测方法具有较好的普适性,可为工程实际应用提供理论指导。

Based on the comparison test platform of the dual-axis tracking trough solar system,the effect of the dust accumulation on the photothermal performance of the trough solar energy system is studied through theoretical analysis and experimental tests.The dust reflection factor and correction coefficient of the acquisition factor are introduced to quantify the effect of dust accumulation on the photothermal performance of the system.The results show that the dust on the condenser has a significant effect on the concentrating characteristic of the focal plane.The uneven distribution of the dust causes more serious scattered radiation.As the amount of dust increases,the energy obtained by the focal plane within a certain size decreases.The energy flux density at the center of the focal plane is reduced,and the receiver with small aperture is more sensitive to the change of energy that can be collected on the focal plane.To ensure the correction coefficient of the acquisition factor of the trough concentrator is greater than 0.90,the dust reflection factor should be less than 4.3%.A prediction model of the effect of dust accumulation on the heat collection performance of the trough solar system is established and verified by the experimental test.The relative error between the predicted value of the model and the experimental value is less than 5.07%,and the good agreement between them is obtained.This prediction method has good universality and can provide theoretical guidance for practical engineering applications.