Shading model for exterior horizontal fins in front of a window,
in function of the fin angle. The control input Ctrl
can either be used for controlling the fin angle, or its horizontal displacement.
The horizontal displacement option assumes that the fins can be displaced
horizontally at the exterior of the window such that they are either in front or
next to the window.
We assume that the fins fully cover the window unless the horizontal
displacement option is used.
The fin angle beta
should be positive.
We compute the shaded fraction of the direct solar irradiation and assume
that indirect reflect effects are negligible.
The diffuse solar irradiation is correct by assuming that the diffuse
solar irradation originates from a solar altitude angle of 30 degrees,
which is an approximation to reality.
The ground diffuse solar irradation is not modified.
Parameter t
is the fin thickness,
s
is the vertical spacing between the fins and
w
is the fin width.
If use_betaInput=true
,
the input Ctrl
is used to control the angle beta,
such that beta
in the figure equals Ctrl
.
Note that beta
must have radians as a unit.
If use_displacementInput=true
,
the input 0 < Ctrl < 1
is used to control the horizontal
displacement of the fins.
For Ctrl=0
, the fins are moved away from the window,
into the plane of the figure below,
such that no sun light is blocked.
Either use_displacementInput
or use_betaInput
should be false.
See the figure below for an illustration.
This model has no dynamics.
The implementation is illustrated using this figure: