[TRNSYS-users] Components order

[David BRADLEY]

Alessandro,
   Yes, the component order can have an impact on the simulation's 
convergence although it is rare in my experience. The TRNSYS kernel 
calls the components in the order in which they appear in the input 
file. The kernel also determines that convergence has not been reached 
after 30 iterations in a timestep (although you can change the 
30-iteration limit if you wish). If you have components in an illogical 
order, it may take the system more iterations to solve than if you have 
the components in a logical order. If you have got a complex system 
anyway (where multiple iterations are needed in order to solve) then an 
non-ideal component order can push you over the iteration limit.
   I try to adjust the component order so that the components appear in 
"flow order" - in other words so that the components are called in the 
same order in which liquid flows through them. Of course there are often 
loops so you have to decide a component that will be first in the list. 
Since pumps set the flow for all downstream components, they are a good 
choice.
Kind regards,
  David


On 11/15/2013 06:44, Bellini Alessandro wrote:
>
> Dear TRNSYS Users,
>
> I have some convergence problems running a Complex Solar Thermal 
> System (30 active components) when I made parametrical analysis.
>
> The model stop at certain time of simulation without giving error in 
> the .LST file and "freezing the screen".
>
> I have enough thermal capacity (pipes and storages) in every circuit 
> so I try to solve the problem changing the "components order" in the 
> "Global Info" and for some cases this solution works well.
>
> Have anybody found the same problem?
>
> I would like to know if there are rules to follow in the "components 
> order" definition or where I can find some information about it?
>
> Thanks for the support
>
> Regards
>
> Alessandro Bellini
>
> Institute for Renewable Energy
>
> *EURAC*research
>
> Institute for Renewable Energy
> Via Luis-Zuegg 11, I-39100 Bolzano
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>
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-- 
***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
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d.bradley at tess-inc.com

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