[TRNSYS-users] stability criteria not fullfilled

[gizmoog]

Michael,

I Had this problem. I join the answer received :

--------------------

Gizmoog,
Marion forwarded your problem to me.
Actually with your defined wall ( heavy, very well insulated) the transfer function method reaches its limits.
We would suggest to simulate only the concrete part as thermal mass while the insulation part can be simulated as resistance. As the insulation material has a low thermal mass this will not create a big error.

With kind regards
Monika Schulz

TRANSSOLAR Software Team
mailto:hotline at transsolar.com 






> > -----Ursprüngliche Nachricht-----
> > Von: gizmoog [mailto:gizmoog at free.fr] 
> > Gesendet: Sonntag, 25. Februar 2007 19:39
> > An: hotline
> > Betreff: Re: AW: [TRNSYS-users] problems with creating new wall
> > 
> > 
> > Dear Marion,
> > 
> > Actually, I created a new layer (ground for a "green" ceiling), and I  
> > can't find my mistake...
> > You'll find my bui file enclosed. The layer is in wall 
> > TTERVEG1 and is 
> > named TERRVEG1. I had to limit it to 5 cm but in fact, it 
> > should be 30 
> > but I can't...
> > 
> > regards,
> > gizmoog
> > 
> > hotline a écrit :
>   
>> > > Dear gizmoog,
>> > >
>> > > Did you use layers from the library or did you create new layers? 
>> > > Often this error message results from incorrect units of 
>>     
> > user defined 
>   
>> > > layers.
>> > >
>> > > In addition, this message may appear if you define a very heavy or 
>> > > very light walls.
>> > >
>> > > In order debug your problem you may send the BUI file.
>> > >
>> > > Cheers,
>> > >
>> > > Marion
>> > >
>> > >
>> > > -----Ursprüngliche Nachricht-----
>> > > Von: trnsys-users-bounces at engr.wisc.edu 
>> > > [mailto:trnsys-users-bounces at engr.wisc.edu] Im Auftrag von gizmoog
>> > > Gesendet: Mittwoch, 21. Februar 2007 19:30
>> > > An: trnsys-users at engr.wisc.edu
>> > > Betreff: [TRNSYS-users] problems with creating new wall
>> > >
>> > >
>> > > Dear users,
>> > >
>> > > I just tried to create a new wall in TRNBuild but when I 
>>     
> > try to save 
>   
>> > > my
>> > > work, it tells me :
>> > > "Error creating the wall transfer function coefficients: 
>>     
> > stability criteria not fullfilled check layer definition 
> > (thickness, ratio of conductivity/density) Please check the 
> > inf file for further information"
>   
>> > >
>> > > and I check everything but noting seems to be wrong... 
>>     
> > nothing better 
>   
>> > > in
>> > > the inf file except i know wich wall is responsible for 
>>     
> > that but I don't 
>   
>> > > know what to do more...
>> > >
>> > > any ideas ?
>> > >
>> > > gizmoog
>> > > _______________________________________________
>> > > TRNSYS-users mailing list
>> > > TRNSYS-users at engr.wisc.edu 
>> > > https://www.cae.wisc.edu/mailman/listinfo/trnsys-users
>> > >
>> > >
>> > >
>> > >   
>>     
> > 
>   
------------------------------------------

Hartl Michael a écrit :
> Dear TRNSYS-users,
>  
> I'm struggling to create some wall types for a multizone building.
>  
> I get the message:
>  
> "error creating the wall transfer function coefficients:
>  
>  stability criteria not fullfilled
>  
>  check layer definitions (thickness, ratio of conductivity/density)"
>  
> Of course, I have already re-checked the layer definitions.
>  
> This message appears for wall types with quite a massive layer (e.g. 
> bricks 0.53m) and an additional insulation (e.g. up to 0.16m). Also it 
> appears when modelling the uppermost slab with a layer of wood (e.g. 
> 0.20m) and insulation (e.g. 0.16m).
>  
> Unfortunatelly I couldn't figure out yet how to create these kind of 
> wall types without having the error message.
>  
> I appreciate any suggestions,
>  
> Michael
> ------------------------------------------------------------------------
>
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