Re: [TRNSYS-users] convergence criteria in TRNSYS

["Jeff Thornton" <thornton@tess-inc.com>]

<Which are the variables are used in the convergence criterium in a
simulation; is
it the parameters which are exchanged between the types or the indoor air
temperature?
Is it possible to use indoor humidity as a parameter to determine
convergence?>

TRNSYS relies on the fundamental idea that if the time independent
variables (parameters) are known to a model, and the time dependent
variables (inputs) are provided to the model, then the model can calculate
the time-dependent outputs - and that these outputs WILL NOT change unless
the parameters and/or inputs change.  Since parameters are fixed for the
duration of the simulation, this implies that the only way for outputs to
change is if the inputs to the model change (including the value of time).
 With this approach, TRNSYS then determines convergence by seeing if the
inputs to a model have changed since the last time the model was called. 
In your case, the program checks to see whether any of the inputs to the
Type 56 model, or any of the inputs to your user-written model have
changed.  If so, then the model is recalled, outputs are recalculated,
input variables are updated and convergence is checked again.

Hope this helps.

Jeff

Jeff Thornton
President - TESS, LLC

2916 Marketplace Drive - Suite 104
Madison WI 53719 USA

Phone: 608-274-2577
Fax: 608-278-1475
E-mail: thornton@tess-inc.com
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