Re: [TRNSYS-users] Type 8, error#206

["Diego A. Arias" <daarias@wisc.edu>]

Dear Stefan,

From the description of your problem, it may be possible that the value 
of infiltration is too high.   Therefore, the state of the system 
differs significantly from one state to the other.  I would recommend 
that you reduce the value of infiltration and see if this helps.
Please try this solution with the successive substitution solver.  
Powell's method was written in order to improve convergence of the 
system, by solving a reduced set of coupled equations/components. I 
don't see why the successive substitution solver would not work.
Best regards,

Diego


Stefan de Kool wrote:

> Dear all,
>
>  
>
> I have an atrium with temperature controlled (on/off) natural 
> ventilation in TRNSYS with TRNFLOW. I use a 3stage room thermostat 
> type 8b to control ventilation openings at the roof and on the 1st 
> floor. The control signal of the type 8 gives stranges results though 
> and tends to oscillate for no appearant reason. When I use Powells 
> method, the signal is okay but somewhere halfway the simulation (begin 
> of summer), I get error 206 at multiple times:
>
>  
>
> TRNSYS ERROR # 206
>
> THE SOLUTION CAN NOT BE FOUND AT TIME 2532.62
>
>  
>
> Finally resulting in
>
>  
>
> TRNSYS ERROR # 204
>
> THE NUMBER OF UNSUCCESSFUL TIMESTES EXCEEDS LIMITS
>
>  
>
> Does anyone have an idea what can be wrong? Decreasing the timestep 
> has no effect; application of a deadband also does not help; the 
> errors occur earlier in the simulation when I use a larger deadband...
>
>  
>
> Kind regards
>
> Stefan de Kool
>
>  
>
>  
>
>  
>
> Cauberg-Huygen Raadgevende Ingenieurs
>
> Lokatie Rotterdam
>
>  
>
>  
>
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>
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>  


--

Diego A. Arias
TRNSYS Coordinator
Solar Energy Laboratory
University of Wisconsin - Madison
1500 Engineering Drive
Madison, WI 53706