[TRNSYS-users] Convergence failure in the simulation

David Bradley bradley at tess-inc.com
Tue May 22 09:02:46 PDT 2007


Chun Kwong,
   Convergnce problems are a result of one of two things usually. 
Either there is not enough thermal capacitance in a given flow loop 
(such as a piping network) or the time step is too big. If I recall, 
your simulation was using a 1 hour time step. I would recommend 
starting by reducing that time step to 0.125 hours to see if that 
solves the convergence problems. The bore field and the building in 
your system should be providing adequate thermal capacitance.
Kind regards,
  David


At 21:17 5/21/2007, h8304506 at hkusua.hku.hk wrote:
>Dear all.
>
>I am simulating a GSHP system, but receive warnings that some units do
>not converge at particular time steps.  The simulation stops after the
>number of warnings reach a limit.  I try to adjust the minimum
>relaxation factor and tolerance of convergence in the control card,
>but it seems to have no improvement.  Please advise how I can fix it?
>Thank you!
>
>Yours sincerely,
>LEE, Chun Kwong
>PhD student
>Department of Mechanical Engineering
>University of Hong Kong
>
>
>
>
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>TRNSYS-users at engr.wisc.edu
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