[TRNSYS-users] MULTIZONE BUILDING - SHADING RATIO OF A WINDOW IS LARGER THAN 1 OR LESS THAN 0

[hotline]

Manfred,

The reduction of orientation may cause the encountered error.
The calculation of the shading matrix is based on the "true" orientation of the surface.
If the position of the sun patch is behind the surface the sunlit factor in the shading matrix is set to 99. (further information: Trnsys18\Documentation\ 05-MultizoneBuilding.pdf)
Thus, it might happen that a window receives direct radiation due to the modified orientation,  but it wouldn't for the "true" orientation.
Type56 encounters a mismatch (direct radiation but sunlit fraction 99. ) und returns the mentioned error message.


Kind regards,
Marion

Transsolar Software Team
hotline at transsolar.com

Transsolar
Stuttgart | Munich | Paris | New York

Transsolar Energietechnik GmbH | Curiestrasse 2 | 70563 Stuttgart | Germany
CEO: Matthias Schuler, Thomas Auer, Stefan Holst, Dieter Schnelle
Registered at Amtsgericht Stuttgart HRB 23347 | USt-IdNr.: DE 152272639


Von: TRNSYS-users <trnsys-users-bounces at lists.onebuilding.org> Im Auftrag von Manfred Schindler via TRNSYS-users
Gesendet: Donnerstag, 14. Oktober 2021 11:46
An: trnsys-users at lists.onebuilding.org
Cc: Manfred Schindler <ma0022 at technikum-wien.at>
Betreff: [TRNSYS-users] MULTIZONE BUILDING - SHADING RATIO OF A WINDOW IS LARGER THAN 1 OR LESS THAN 0

Hallo everyone,

I'm having a problem with the simulation of my 45-zone-model - at timestep 8,75 (0,25 h steps) the error message(s) "MULTIZONE BUILDING - SHADING RATIO OF A WINDOW IS LARGER THAN 1 OR LESS THAN 0" appears.

For all my windows I have an external shading which is an input from dck. But I don't have a separate equation per window. I simplified the orientations to N-E-S-W have these orientations for each zone --> means 4x45=180 shading equations. I checked the equations and the printed values - are correct - and also set it to constant 0 - still the error messages.

In an existing conversation from the archieve ("2nd error generating shading/insolation matrix ->  too many shaders on projection plane") the problem was solved by adding MIN and MAX function to the shading equations - with this addition also the iterations in-between, not just the last iteration, have to be between 0 and 1. But I tried it and it didn't help.
In the same conversation a previous error was solved by reducing the surface numbers, because the surface numbers were higher than 999 --> could this be the problem? I have a quite big building with almost 1700 surfaces, especially a lot of single windows. I could simplify the windows and combine them per wall-surface to one big window, but I want to check your expertise first.

Kind regards,
Manfred Schindler
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