The function of skylights is to utilize smaller window openings to reflect sunlight from outside and near the windows into deeper areas inside.
Under normal conditions, direct radiation is 4 to 7 times stronger than scattered radiation, and skylights primarily utilize direct light. Direct radiation from outside is reflected into the indoor ceiling through smaller upper window openings by the skylights, and after scattering reflections from the ceiling, the skylights uniformly illuminate areas far from the windows. With the window area unchanged, the skylights ensure sufficient lighting in areas far from the windows, enhancing the uniformity of indoor lighting and visual comfort. The smaller upper opening area, although allowing some reflected radiation, does not significantly increase the indoor air conditioning load. Moreover, the skylights outside play a role in exterior shading, which is beneficial for improving the thermal comfort near the windows, reducing the air conditioning load and direct glare.