[TRNSYS-users] First message and a couple questions.

[David BRADLEY via TRNSYS-users]

Med. Omar FANNAN,

   This list is intended as a place in which users can assist other 
users although it is often used as a starting point for technical 
support. If you have specific technical support questions you should 
email them to the distributor from whom you (or your institution) 
purchased TRNSYS. If you aren't sure who to contact then please send me 
an email directly (i.e. not to this list) and include the information 
from your user17 (which can be opened with a text editor).

   The list and description of TRNSYS access functions such as 
getIsConvergenceReached() can be found in the 07ProgrammersGuide manual 
in the ..\Trnsys17\Documentation\ folder.

   Convergence can be impacted by component order. You can change the 
component order by clicking on the "control cards" tool in the left hand 
toolbar (where you set the simulation start and stop times) and then 
switching to the component order tab.

   Convergence problems can be hard to track down because there can be 
many causes. Here are a few hints about them.

- make sure that your timestep is not too long. TRNSYS can only make one 
control decision per timestep. If you are using a long timestep and are 
using a controller model to control a system that has a time constant 
shorter than your timestep you are going to run into convergence 
problems. Time steps should typically be on the order of 1 to 5 minutes.

- make sure you have enough thermal capacitance in your system. This is 
basically the same as the above point; thermal capacitance increases the 
time constant of the system and causes it to respond more slowly (and 
more realistically) to control state changes.

- you can look in the *.lst and *.log files to find out which components 
are failing to converge.

kind regards,

  David



On 06/20/2016 05:12, Med. Omar FANNAN via TRNSYS-users wrote:
> Greetings,
>
> First of all, I really don't know if I'm posting in the right section, 
> but it never hurts to try.
>
> I'm only just starting to use TRNSYS, so excuse my questions if they 
> seem silly :
> Is there a listing of intrinsic TRNSYS routines (like 
> getIsConvergenceReached and such?)
> How can I resolve convergence problems?
> Is the order of execution of the UNITS important?
>
> Thank's in advance,
>
> Med. Omar FANNAN (AKA MOF)
>
>
>
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users at lists.onebuilding.org
> http://lists.onebuilding.org/listinfo.cgi/trnsys-users-onebuilding.org

-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

P:+1.608.274.2577
F:+1.608.278.1475
d.bradley at tess-inc.com

http://www.tess-inc.com
http://www.trnsys.com

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