Re: [TRNSYS-users] bug: "stability criteria not fullfilled"

["Matt Duffy" <duffy@tess-inc.com>]

Catherine,

You might want to try increasing the timebase in the Outputs window in
TRNBuild.  Please refer to section 6.4.1.14 in the Multizone Building
Manual for more info.  ASHRAE recommends a timebase of 1 hour, but 2-4
hours may be used for heavy construction (Ref. 6.2.10.9).

Best regards,

Matt Duffy



----- Original Message -----
From: "Catherine Massart" <trnsysmassart@gmail.com>
Sent: Thu, July 31, 2008 8:23
Subject:[TRNSYS-users] bug: "stability criteria not fullfilled"


*Dear TRNSYS users*
**
*I want to make simulations on highly insulated buildings.*
*Some of the walls I created bring a bug.*
**
*« 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 »*
**
*I heard this could be solved by changing the density and capacity of the
layer that causes the problem (here, a ceiling wood structure insulated with
40cm of wood fiber pannels (Steico))*
*But I cannot do this because I want to evaluate the impact of the inertia
on the inside temperatures.*
*I tried by deviding the material in 2 layers: one would have the same
inertia and the other, massless, would bring the thermical resistance. It
doesn't work, stability criteria is still not fullfilled...*
**
*Can someone help me?*
**
*Thanks a lot*
**
*Catherine Massart*
*UCL-Belgium*


----- End of original message -----