太阳辐射直散分离模型的改进及应用

Comparative Study of Solar Beam-diffuse Radiation Separated Model

获取太阳散射辐射是太阳能资源评估和并网光伏系统设计的必备条件,鉴于近年来地表太阳辐射特征发生了显著变化,先前的太阳辐射直散分离模型已无法真实反映太阳辐射的变化规律,提出一种散射比(Hd/H)的估算方法。以北京市、上海市和武汉市为例,先根据三地10年实测辐射数据对Erbs模型进行本地化修正,再引入日照百分率(n/N)建立了拟合效果较好的Hd/H回归方程,然后用三地2011年逐月太阳辐射和日照时数等实测数据校验模型的准确性,对4种直散分离模型进行了误差分析。结果表明,采用双变量模型估算精度更高,大部分月份的相对误差均在10%以下。新建模型符合当地实际的辐射特征,对光伏系统的设计具有指导和借鉴参考意义。

Solar diffuse radiation data is a fundamental input for assessing solar energy resource and designing grid connected photovoltaic system.Due to the characteristics of ground solar radiation change significantly in recent years,previous solar beam-diffuse radiation separated model can not truly reflect the variation of solar radiation.A method for estimating diffuse radiation fraction Hd/His proposed.Take Beijing,Shanghai and Wuhan as an example,according to the local measured radiation data during 10 years,with localized revising of Erbs model,a new model is built.Then the relative number of sunshine hours n/Nis introduced to establish the new regression equation with better fitting effect.Furthermore,the accuracy of model is validated using measured data of solar radiation and sunshine hours in 2011.Comparison of four models is performed through error analysis.It is found that the model including two variables is of high prediction accuracy.In most months,the relative error is lower than 10%.The new model is in line with the radiation characteristics of the local actual,which has reference significance for photovoltaic system design.