Plane orientations and radiation components

Last update: Jul. 2015

    Horizontal plane - fix-tilted plane - normal plane

Radiation components over the horizontal plane

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Radiation components over the tilted plane

NB: the irradiation collected by a tilted surface is composed of a part of direct irradiation (as soon as the sun is visible by the panel), a part of diffuse irradiation coming for the portion of the sky vault visible by the panel, and a part of irradiataion reflected by the ground. The albedo caracterizes the reflective capacity of the ground. The default value is 0.2. If the ground is not very reflective, like for instance dark ground, just set 0.1.
Anyway, the reflected part is small compared to the other components, so the ground albedo is a second order input parameter. Author: Pr Lucien Wald, MINES ParisTech, March 2015.

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Radiation components over the normal plane

1-axis solar tracker (East-West rotation, axis oriented North-South), you may specify:

  • Plane tilt = -999
  • Plane azimuth = 90 (is northern hemisphere) and ? (if southern hemisphere)

The tracking model in Helioclim-3 is very simple. It does not take into account limit angles or any "mechanical constraints". Every minutes, we simply compute the tilt or the azimuth (if 1-axis tracking) or both (if 2-axis tracking) that minimizes the angle between the sun direction and the panel normal. It's simple maths.Top of page