[TRNSYS-users] Radiation processor - bug in latest TRNSYS update?

[David BRADLEY]

Ciarán and Sarah,

> 2) If I'm not mistaken, you're right, the incidence angle is indeed the angle between the incident beam and the normal of the surface. However for me also the incidence angle profiles do not seem realistic for surfaces which are not horizontal (for horizontal surfaces the incidence angle profile is good, between 90 and 0ish degrees; but for example on a 45 degree slope facing south, the incidence angle jumps from 90 to approx. 120 degrees at dawn and dusk...). Maybe someone else can help you with that one (?)
the incidence angle is indeed the angle between the beam solar and the 
normal to the surface. At night, the incidence angle is set to an 
arbitrary value. However, when the sun is up we do not clip the 
incidence angle to force it to be between 0 and 90. During summer 
months, the sun comes up well to the north of the east/west axis (in the 
northern hemisphere) so the incidence angle can be greater than 90, 
which simply indicates that the sun is behind the surface in question.
Best,
  David


-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com