Source: Wikipedia

The Apparent Motion of the Sun and Its Impact on Solar Power

Understanding Sun’s Apparent Motion

The apparent motion of the sun, caused by the Earth’s rotation, results in changing angles at which sunlight strikes the Earth. This motion makes the sun appear to move across the sky from a fixed point on Earth, with its position varying based on the Earth’s location, time of day, and time of year.

Impact on Solar Power Collection

This apparent movement of the sun significantly affects the power received by solar collectors. When sunlight is perpendicular to the collector’s surface, the power density is at its maximum. However, as the angle between the sun and the surface changes, the intensity of sunlight reaching the surface decreases. At angles where the surface is parallel to the sun’s rays, the light intensity essentially drops to zero. For other angles, the power density is proportional to the cosine of the angle between the sun’s rays and the surface normal.

Factors Affecting Sun’s Angle

The angle between the sun and a fixed Earth location is influenced by the longitude of the location, time of year, and time of day. Additionally, the sunrise and sunset times are determined by the location’s longitude. To accurately model the sun’s angle relative to a fixed position on Earth, factors such as latitude, longitude, day of the year, and time of day need to be considered.

Source: NASA

Feel Free to comment your thoughts.