[TRNSYS-users] TRNSYS Message 441 and 437

[David Bradley]

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: <mailto:finocchiaro at dream.unipa.it>finocchiaro at dream.unipa.it
>
>
>
>_______________________________________________
>TRNSYS-users mailing list
>TRNSYS-users at engr.wisc.edu
>https://www.cae.wisc.edu/mailman/listinfo/trnsys-users

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