[TRNSYS-users] Type56 - TRNBuild error

[David Bradley]

Dear Mika,
  Typically with thicker walls, you have to use a larger timebase; the 
default is 1 hour and I notice that your building finds a solution with 
a 1 hour timebase. The coefficients that are being generated for the 
wall are basically weighted averages on the factors that affect energy 
transfer through the wall (factors like temperature difference across 
the wall). The weighted averages tell how important a particular factor 
was one timebase before the current time, two timebases before the 
current time, three timebases before the current time, etc. The thicker 
your walls, the farther back into history you have to go in order to get 
a full picture of how energy is transfered through the wall. 
Coefficients are generated for the last 20 timebases; by using a 0.1h 
timebase, you are only allowing TRNBuild to look back 2 hours. With a 1 
hour timebase, you are allowing it to look back 20 hours. In your case, 
the important response of the wall occurs somewhere between 2 and 20 
hours ago.
Best regards,
 David


Yoshinaga Mika wrote:
> Dear David and all,
>
> I'm modeling a RC-house with high insulation by TRNbuild.
> But putting the thick insulation layer into wall type makes TRNBuild Error
> window "Error creating the wall transfer function coefficients" pop up. The
> timebase is set as "0.1".
>
> I attached the bui file. 
> * RCOUTWALL wall type has 150mm concrete layer and 100mm GW insulation layer
>
> * RCROOF wall type has 130mm concrete layer and 100mm GW insulation layer 
> If you click "save" button, the error window pop up.
>
> How can I handle it?
> Thank you in advance!
>
> Kind regards,
>
> Mika Yoshinaga
> Meijo university, Japan
>   
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