Zonnecomponent

Zonnecomponent is a term used in Dutch-language technical literature to denote the component of a vector or quantity that lies in the direction of the Sun. In practice, it is the scalar projection of a vector v onto a unit sun vector s, defined as v_s = v · s. If the sun vector points toward the Sun, the zonnecomponent describes how much of v is oriented in that direction. In many solar-energy and solar-geometry calculations, only the portion that actually faces the Sun contributes, so engineers often use max(0, v · s) to represent the contributing direct solar component.

Applications and usage

In solar radiation modelling, the zonnecomponent helps decompose quantities into a direct solar part and other components such as diffuse radiation. For surfaces with normal n, the direct solar contribution is proportional to the cosine of the incidence angle, cos(theta) = s · n, making the zonnecomponent a practical way to express this projection. The concept is used in photovoltaic performance assessments, shading analyses, and building energy simulations to estimate how much solar energy interacts with a given surface or system.

Computation and example

If a vector v has magnitude 12 and forms a 60-degree angle with the sun direction s, then the zonnecomponent is v_s = 12 cos(60°) = 6. For a surface with normal n, the direct contribution on that surface is v · n = |v| cos(phi), where phi is the angle between v and n, and cos(phi) equals s · n.

Notes

The concept also applies to other contexts where projecting onto a sun-directed axis is useful, such as solar wind or atmosphere-related calculations.