Re: [EnergyPlus_Support] Exceeding max iterations , again!

["Michael J. Witte" <mjwitte@xxxxxxxx>]

Sometimes the max iterations error means that the solution is changing wildly
each iteration which would mean the result is invalid.  Sometime it is only
changing by a small amount just beyond the convergence limits which would mean
the solution is valid.  It is impossible for the user to know.  A small number
of max iteration errors are acceptable.

Is this the same run that we were looking at in early August?  If so, you
should be able to get rid of nearly all of the max iteration warnings by
reducing the controller tolerances.  Search for every occurence of "tolerance"
and change the value to 0.000001.

Mike


On 2 Sep 2004, at 2:25, beyangj wrote:

>
> Dear Mike,
>
> Thank you very much for your advices.I changed the values for
> the "convergence tolerance" in controllers and other HVAC
> components, but it didn't take effect. There are also many warnings
> about max iterations. The last warning is as follow:
> ** Warning ** SimHVAC: Exceeding max iterations continues...1300
> There are no return fan and zone exhaust fan in the  VAV system. I
> still don't know why there are so many max iterations. I wonder
> whether too many iteration will affect the simulation results?
>
> Best,
>
> Stewart
>
>
>
>
>
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
>
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
>
> Attachments are not allowed -- please post any files to the appropriate folder
> in the Files area of the Support Web Site.
>
> Yahoo! Groups Links
>
>
>
>
>
>
>
>



========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support
EnergyPlus-Support@xxxxxxxx




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