Hello,
Sorry to send you again the same topic but my doubts persist, after many many tests, about the window values used by TRNSYS for transmission losses.
First of all, when I test a window with only glazing (area frame = 0), it seems that the 2 outputs of TRNBUILD Uwin and B4_QT (transmission into a wall, with a test with constant values of internal and external temperatures and no radiation) give me the same Uglass with convective heat transfer coefficients equal to convective + radiative coefficients, it means front coefficient = 27 kJ/hm²K = 0.13 m²K/W and back coefficient = 89 kJ/hm²K = 0.04 m²K/W.
Is it also what you found ? How could you explain me that ?
Then, also with this test of 100% glazing window, if I use a glass type I created with WINDOW 6 without frame and spacer (because I want to choose after the spacer and the frame in TRNBUILD), which is shown in WINID with a indicative Ug of 1.07 W/m²K, correct value for this type, when I look the 2 outputs Uwin and B4_QT, these ones give me a Uglass of only 0.57 W/m²K !
Could you explain to me what I did wrong? And more especially, how TRNSYS could calculate this value?
Thanks a again for all help you could give me to be sure of TNSYS values.
Best Regards,
Pauline GELIN
Ingénieur Conception environnementale
10 avenue des canuts
69120 VAULX EN VELIN
T : 04.37.45.33.33
Ligne directe : 04.37.45.33.47
De : Pauline GELIN
Envoyé : lundi 27 mai 2013 14:43
À : 'trnsys-users'
Objet : Persistent questioning about window definition
Hello,
Sorry to insist but I am really blocked by these questions of data. I am not at all sure of the TRNSYS simulations.
Are there no one else who has met these misunderstandings?
Pauline GELIN
Ingénieur Conception environnementale
10 avenue des canuts
69120 VAULX EN VELIN
T : 04.37.45.33.33
Ligne directe : 04.37.45.33.47
De : Pauline GELIN
Envoyé : jeudi 23 mai 2013 09:49
À : trnsys-users
Objet : Persistent questioning about window definition
Hi,
Then I used a glass that I had created from WINDOW6 software, it turned out that the Uwin value, given output by TRNBUILD and used in the simulations, did not correspond to what I expected, result due to the Ug value from database and percentage frame and Uframe filled in TRNBUILD.
After many tests, it appears that the calculated Uwin TRNBUILD differs if I take a glazing created in WINDOW6, for which I have not information of spacer and, or a glazing initially given in the TRNBUILD database.
While Uframe percentage and spacer values indicated in my database windows are the same.
Does anyone know where does this difference come from?
What values of Uframe, and percentage frame and spacer, does TRNBUILD consider : those entries in the database glazings or those filled in the database window that is created for each project?
This misunderstanding about the values considered by TRNBUILD is not at all reassuring.
Especially when I tested a window created with WINDOW6 and one from the initial TRNBUILD database with 100% glass (so without frame).
And in the first case I found a Uwin value equal to 0.3 instead of Ug equal to 1.07.
And in the second case I found a Uwin value of 1.22 for the same value of Ug equal to 1.07.
Thanks a lot in advance for all your answers.
Best regards,
Pauline GELIN
Ingénieur Conception environnementale
10 avenue des canuts
69120 VAULX EN VELIN
T : 04.37.45.33.33
Ligne directe : 04.37.45.33.47