|
Dear Mehdi, thanks for resending your
simplified files! The error is due to very
low radiation data on the north façade of your model from Type 109 of 0.02
KJ/hr m². Type 56 does a radiation
distribution for this very low value which yields to a total distribution error
of radiation entering all windows of 3.63 KJ/hr for your 3 floor window. The 2floor model runs
fine because there are less windows leading to an error smaller than 3.6 kJ/hr. As a quick fix I suggest to
set radiation input to Type 56 lower than 1 KJ/hr m² to 0 by the following IT_N_180_90 =
[109,36]*GT([109,36],1) IB_N_180_90 =
[109,37]*GT([109,36],1) In addition, I put it on
my list for Type56 improvements. Best regards, Dipl.-Ing.
Marion Hiller Geschäftsführer:
Dipl.Ing. Matthias Schuler, Dipl.Ing. Thomas Auer, Dipl.Phys. Stefan Holst,
Prof. Dipl.-Ing. Bleicher Von: Mehdi
Shahrestani [mailto:mahdishahrestani@yahoo.com] Dear TRNSYS team and users It is around
10 days that I have got stuck in simulation of a building. After many things
that I have already checked, it seems that there is a bug in Trnsys. Here, I am
going to raise the issue in detail hoping to get some response from users and
Trnsys bodies. Project: Modelling of a
building with 3 floors without considering system (just using type 56) Each floor has
20 zones and the plans of all 3 floors are the same. Followed
process: In the first
round the building was drawn in Trnsys3d-SketchUp and imported into the Trnsys.
After importing the *.idf file, a *.tpf file was automatically generated and
was working very well. The problem came up when I needed to reduce simulation
time step from 1 hr to 0.2 hr. (for controller settings in the next steps of my
project) Any way, a
simple type 56 for a building with 3 floors, each floor 20 zone was not working
with 0.2hr simulation time step. The
error is: “Internal error in solar radiation distribution (sumsitot)
of 56.388 % at time 56.40wave length band
no.3 1:total solar, 2:visual solar, 3:non visual solar” I was checking
every thing but nothing was wrong. Finally, I sent an Email for users and asked
for help. Christian from TRANSSOLAR and Matt from TESS kindly replied. Matt
suggested me to follow the Christian advice and Christian wrote: “One reason for this can be that in your 3DModel you have
infinitesimal small surfaces. Please check if this is the case and if so you'll
have to redraw the geometry“ Then, I
checked every little part of the 3D model in Sketchup and also imported model
in studio but there was not such evidence. Even though I
was quite sure that there is no such a little surface I redraw the entire model
several times (at least 10 times) precisely but the result was the same and
after importing the *.idf file into studio exactly at 56.4 hr the error comes
up every time. In the next
try I decided to draw and import building floor by floor. After drawing the
first floor, it was imported to the studio. Generated *.tpf file including Type
56 ran with 0.2 hr simulation time step. The result was perfect, and I decided
to check the building with 2 floors. To make the drawing I used the drawing of
the first floor (previously drawn) and copy it on the top of the first floor as
second floor and then import the related *.idf file into studio. Type 56 of the
building with two floors was working in 0.2 hr time step perfectly without
error. Then, I repeat the process and copy the drawing of the second floor and
paste it as third floor in Sketchup. After importing the *.idf of the
building with 3 floors, type 56 was only able to run in simulation time step
1.0 hr. when I was reducing time step to 0.5 or 0.2 the previous error came up.
All in all,
this approach proved that there Christian’s expectation was not correct
because if it was correct I could not run the related type 56 for the first
floor and second floor without error as well.( third floor was copy and paste
of second floor) Even though it
was quite clear that there is no any small surface (Christian expectation) I
was thinking maybe there is some problem about connection between Sketchup and
studio. Therefore, I decided to insert entire building manually in type 56. The
result of manual filling type 56 was 100% similar to the importing building
from Sketchup. That means, first floor and second floor was running perfectly
in different simulation time step (0.2 hr , 0.5 hr and 1 hr) but just when I
added the third floor, type 56 came into the same error (mentioned above) at
the same time (56.4 hr). By following
these two approaches I have got sure that the error is not because of small and
unattended surface (Christian expectation) and also is not because of importing
*idf file from Sketchup. This error has
also detected by other users Xavier
(2004) which Michaël Kummert was replied and accepted the bug in version 15. My
expectation: 1- There are limits on number of zone for each type 56. 2- Weather component (type 109) is not able to deal with some time
steps. 3- There is a bug in type 56 to run model with time steps less than 1.0
hr. 4- There is a bug for solar radiation distribution within type 56. For further
detail following files are attached: 1- Folder 1 including related files of building with two floors
developed in Sketchup and imported into Trnsys which works fine in
different time steps (*.idf, *.tpf, *.dck and *.b17 files) 2- Folder 2 including related files of building with three
floors developed in Sketchup and imported into Trnsys which is not working
in time steps less than 1.0 hr (*.idf, *.tpf, *.dck and *.b17 files) Hereby, I was
wondering if anybody could help me. I am not a freelance researcher; I am a PhD
student with dispread need on doing simulation. I hope you consider user
situation with your kind responses. Sorry about
the long story and thanks for your time Regards Mehdi
Shahrestani |