The proper method is to set up the panels on the roof. Although the angle of elevation varies with latitude, the principle is that the solar panels should be, as much as possible, perpendicular to the sun at all times.
正確作法應是蓋在樓頂，雖因緯度不同而有不同仰角，但原則就是讓中垂線隨時保持和太陽最小的夾角。