我国最佳倾角的计算及其变化

COMPUTATION OF THE OPTIMUM TILTED ANGLE AND ITS VARIATION IN CHINA

在散射辐射各向同性的假定下,导出了南向倾斜面上实际(或平均)太阳总辐射的最佳倾角公式。该式不仅是地理纬度和太阳赤纬的函数,同时又是水平面上实际太阳总辐射与直接辐射月辐照量之比的函数。我国部份台站的计算结果表明,最佳倾角的计算误差年平均约3°,对应的倾斜面上总辐射量的年平均误差<2％,最大误差<6.5％。

The angle between an inclined plane and a horizontal one is called optimum tilted angle (u) when the total amount of the global radiation received on the plane titled toward equator during a certain period reaches its maximum. Under the assumption that the diffuse radiation is isotropic, an analytical expression for a is developed which is the function of the geographical latitude, declination and the ratio of the global radiation to direct radiation on the horizontal plane (rQS). The annual average errors of a are about 3-4° and the annual average errors of the daily global radiation are less than 2% for all the discussed stations. a is almost a linear function of the geographical latitude for constant declination and rQS. And a increases with the decrease of rQS for constant latitude.