Re: [TRNSYS-users] TRNSYS Message 441 and 437

[David Bradley <bradley@tess-inc.com>]

Dear Pietro,
  There are any number of reasons that you could be getting non
convergence errors in your simulation. It sounds as though there are two
problems. One is that there are problems in calculating the solar
radiation on various surfaces based on the data files that you are using.
To track down those errors, please check your parameters and connections
with whatever combination of weather data reading / radiation processing
components you are using. If you are using a combination of Type89 and
16, I would first check to make sure that the Type16 parameter: Starting
day of simulation is correct.

  The second problem seems to be trouble converging on a solution
for the loop in your simulation that includes unit numbers 40, 24, 23,
25, 41, 27, and 52. Solving the radiation problem may help with this non
convergence but I have my doubts. What you need to do is first try
reducing your time step. Bear in mind that you can only make a control
decision (using Type2 or Type22) once per time step. Next, if you are
dealing with a fluid loop, make sure that you have enough thermal
capacitance in this loop. You should make sure that there is a pipe in
the loop that is large enough to store at least one time step of fluid.
If there is a storage tank in the loop, you usually do not need to add a
pipe. 

Kind regards,
  David

At 04:03 AM 6/30/2005, pietro finocchiaro wrote:
> Dear
> TRNSYS users,
>  
> I made a project of a solar cooling system and it seems to correctly run
> during a yearly simulation, but in the list file appear a lot of warnings
> like the following:
>  
> TRNSYS Message    441 : The inputs to the listed units
> have not converged at this timestep. The values at the last iteration
> will be used and the simulation will proceed.
>     Reported
> information  : UNITS: 40  24  23  25  41 
> 27  52
>
> If I modify the simulation start and
> stop time in order to a have a shorter period of time, the simulation
> give a enormous but different numbers of warnings and the following
> error:
>
> *** Warning at
> time       :     
> 4144.000000
>
>     Generated by
> Unit     :    45
>
>     Generated by
> Type     :    16
>
>     TRNSYS
> Message    437 : The total radiation calculated for one of
> the surfaces has exceeded the solar constant. The component solar
> quantities (beam and diffuse) have been adjusted such that the sum is
> equal to the solar constant
>
>     Reported
> information  : Sloped Surface Radiation Error
>
>   
>
> *** Fatal Error at
> time   :      4144.000000
>
>     Generated by
> Unit     : Not applicable or not available
>
>     Generated by
> Type     : Not applicable or not available
>
>     TRNSYS
> Message    450 : The maximum number of warnings allowed
> per simulation has been exceeded. Please fix these warnings or increase
> the limit on the number of warnings allowed per simulation (LIMITS
> command)
>
>     Reported
> information  : Not available
>
>  
>
> I?m not able to locate the problem. I
> think it has no sense to increase the maximum number of warnings allowed
> per simulation..
>
> Thanks to all,
>
>  
>
> --------------------------------------------------------------
> Pietro Finocchiaro 
> Dipartimento di Ricerche Energetiche ed Ambientali 
> Università di Palermo 
> Tel: +39 (0)91 236277 
> E-mail:
>
> finocchiaro@dream.unipa.it 
>   
>   
>  
> _______________________________________________
> TRNSYS-users mailing list
> TRNSYS-users@engr.wisc.edu
> https://www.cae.wisc.edu/mailman/listinfo/trnsys-users

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