Hi Antoine,
the 2-band model only makes a difference when solar radiation is passing through two selective glazing systems in series.
This is an old example with a visual fraction of 50%. This visual fraction isn’t used, but the exmaple explains the fact well.
Best,
Marion
-----------------------------------------------------------------------------------------------------------------------------------------------------------
Dipl.-Ing. Marion Hiller
TRANSSOLAR Energietechnik GmbH
Stuttgart - Munich - New York - Paris
t:
+49.711.67976.0 f:
+49.711.67976.11
www.transsolar.com/
KlimaEngineering - Technologien für energieeffizientes Bauen und Nutzerkomfort in Gebäuden
Transsolar Energietechnik GmbH, Curiestrasse 2, 70563 Stuttgart
Amtsgericht Stuttgart - HRB 23347
/ Steuernummer: 99073/00911 / USt-IdNr.: DE 152272639
Geschäftsführer: Matthias Schuler, Thomas Auer, Stefan Holst, Dieter Schnelle
Von: TRNSYS-users [mailto:trnsys-users-bounces@lists.onebuilding.org]
Im Auftrag von Antoine Gautier
Gesendet: Mittwoch, 7. Januar 2015 18:00
An: trnsys-users@lists.onebuilding.org
Betreff: [TRNSYS-users] TR: Window data generated by Window software lead to Trnsys Warning
Hi
I hereby post a late answer to an old issue thanks to Hanisch: see below.
I take this opportunity to ask a question concerning the 2-band radiation calculation. Since non-visual glass properties are computed based on solar and visual
properties assuming a constant visual / solar radiation ratio (0.466) I don't understand how a simple calculation with solar properties only (1 band) would lead to different results regarding transmitted solar radiation. By the way when I compute the diffuse
transmittance as QSTRNS/QSEXT for QSEXTBeam=0 I get the exact same value as the hemispheric solar transmittance (Tsol Hemis) from the WINDOW data, whatever the value of the visual transmittance.
Could you please explain how and why the 2-band calculation could differ from 1-band calculation?
Best
--
Antoine Gautier
Solamen
+33 6 58 24 02 60
De : jh-ingenieure [mailto:info@jh-ingenieure.de]
Envoyé : lundi 22 décembre 2014 17:32
À : 'Antoine Gautier'
Objet : AW: [TRNSYS-users] Window data generated by Window software lead to Trnsys Warning
Dear Antonie Gautier,
our lokal TRNSYS-hotline (Transsolar) told us, that TRNSYS uses a different solar-spectrum as windows.
So for glazings with high selectivity negative values for visible transmission can accour.
For solving that problem, they advised to make a one-band rather than a two-band calculation for the windows used in TRNSYS.
To do so, in winlib.dat (as well as in prgwin.dat) the angle dependent values for solar-transmission and reflection should be copied to the values of visible transmission and reflection.
In my case the difference between the two-band calculation (with the warning) and the one-band calculation was about 4%.
The problem should be solved in TRNSYS V18.
Best regards
Mit freundlichen Grüßen
Hanisch
jh-ingenieure GmbH
kiefernweg 31 | 14532 kleinmachnow | t: 033203 87498 | e:
info@jh-ingenieure.de
Mitglied des Vorstands des AIV zu Berlin
Prüfsachverständiger für energetische Gebäudeplanung
Dozent für Wärme- und Feuchteschutz an der HWR Berlin
Auditor für nachhaltiges Bauen (DGNB)
Von: Antoine Gautier [mailto:antoine.gautier@solamen.fr]
Gesendet: Montag, 8. Dezember 2014 13:38
An: 'jh-ingenieure'
Betreff: RE: [TRNSYS-users] Window data generated by Window software lead to Trnsys Warning
Hi Hanisch
Sorry no further insight on that matter.
I let it go considering the rather low discrepancy between calculated and maximum value.
If you get any other information though don't hesitate to let me know.
De : jh-ingenieure [mailto:info@jh-ingenieure.de]
Envoyé : dimanche 7 décembre 2014 21:06
À : antoine.gautier@solamen.fr
Objet : Re: [TRNSYS-users] Window data generated by Window software lead to Trnsys Warning
Dear Mr. Gautier,
I have the same Problem with TRNSYS as you reported in the TRNSYS-mailing-list in April (see below).
Did you find a solution?
If so, would you be so kind to tell me your way to solve the problem.
Thanking you in anticipation.
Wit best regards
Mit freundlichen Grüßen
Hanisch
jh-ingenieure GmbH
kiefernweg 31 | 14532 kleinmachnow | t: 033203 87498 | e: info@jh-ingenieure.de
Mitglied des Vorstands des AIV zu Berlin
Prüfsachverständiger für energetische Gebäudeplanung
Dozent für Wärme- und Feuchteschutz an der HWR Berlin
Auditor für nachhaltiges Bauen (DGNB)
Dear users
I get the following warnings using window data generated by Window software
6.3. I do not get any error during window data generation. Do you know what
I should correct? (I included the detailed window data hereunder.)
Thanks a lot for your help.
*** Notice at time : 0.000000
Generated by Unit : 27
Generated by Type : 56
Message : winlib reader: Incorrect visual transmission
values encountered in Window-ID 116. for an angle of 0 °.
Incorrect value 0.603 will be limited to the possible physically maximum
0.561! Please check your window data!
*** Notice at time : 0.000000
Generated by Unit : 27
Generated by Type : 56
Message : winlib reader: incorrect selectivity of
visual+solar transmission caused a negative value for nonvisual Transmission
Tra_ang_nonvis = -0.026 for Window-ID 116 at an angle of 0 °
Tra_ang_nonvis is set to 0 for this angle