[TRNSYS-users] Thermal mass of glazings

[Marion Hiller]

Wirich,

my experience is that for some special cases the integration of glass capacities make sense.
Especially, if you compare results of glass temperature to measurements and your glazing system has a high solar absorptance in combination with thick glass panes (http://www.ibpsa.org/proceedings/BS2019/BS2019_211101.pdf):

CFS Model Improvement based on Measured Data of a 1:1 Scale Test Mock-up
Comparisons  of  measurements  at  a  1:1  scale  mock-up
with detailed thermal simulation offer a great opportunity
for model evaluation.
Due to the composition of the investigated glazing system
(8  mm  +  8  mm  PVB  laminated  glass,  solar  protection
coating, 5 mm glass and 8 mm glass) the authors extended
the  existing  complex  fenestration  model  (CFS)  of  the
multizone  building  model  of  TRNSYS  by  adding  heat
capacity for glass layers.
Simulation results with and without glass capacity
consideration  are  compared  to  measurements  at  a  1:1
scale facade mock-up.
The results show that the consideration of heat capacity of
the  glass  layers  improves  the  match  to  measured  data
significantly. The extended model resolves issues of high
peak temperatures and a shift in time of occurrence. The
simulation  results  of  the  improved  CFS  model  match
closely to the measurements of the mock-up.


Best,

Marion

Dipl.-Ing. Marion Hiller
+49 711 679 76 32 | hiller at transsolar.com<mailto:hiller 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 Freppel, Wirich via TRNSYS-users
Gesendet: Freitag, 16. Juli 2021 10:02
An: TRNSYS USERS (trnsys-users at lists.onebuilding.org) <trnsys-users at lists.onebuilding.org>
Cc: Freppel, Wirich <Wirich.Freppel at saint-gobain.com>
Betreff: [TRNSYS-users] Thermal mass of glazings

Hello everyone,

As I am conducting thermal simulation in a high glazed zone (conservatory), I am concerned about thermal mass of glazings. According to the documentation, thermal mass is set as null for glazings.
But, after a hard work of fitting between my simulation model and some experimental data, I noticed that my simulation model is "lighter" than the experimental one (air temperature variates more reactively in simulation).
So, I calculated the thermal mass of all inner glazings (well I approximated it) and added the result to the zone capacitance. The result is very encouraging and I'm quite happy with the simulation model as it is set now. However, I would like to have your feedback on this. What would be your judgment on this method as thermal experts and is there another way to add a thermal mass to the glazings ?

Best regards

[02]
Wirich FREPPEL Ph.D
Development engineer
COSMOS - Buildings Energy Performance & Daylighting Group
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Tel: +33 637 053 174
E-mail: wirich.freppel at saint-gobain.com<mailto:wirich.freppel at saint-gobain.com>
www.saint-gobain.com

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