[TRNSYS-users] Limitation of the wall thickness in PREBID

[Wimolsiri Pridasawas]

Hello! 

I model the house by using PREBID for create the building 
description.  When I defined the new type of wall (a thick wall with 
multilayer), the error shows in the 'inf' file that 

  ** ERROR - STABILITY CRITERIA FOR WALL TYPE EXT_2ND              
NOT FULLFILLED

CHECK LAYER VALUES 
             NO FILE GENERATED **

I changed the thickness of some layers, the error is then 
disappeared. I tried to find the relation between the error and the 
thickness of the layer/wall but I cannot find the conclusion. The 
error offen comes when using gypsum board type #115 and Mineral wool 
type #140.

Does anyone have the same problem? Are there any limitation when we 
define the layer/wall thickness?  What is the relation between the 
wall thickness and the ratio of conductivity/density?

This is the properties of the wall that I always have a problem:
Layer					material #		Thickness (m)
-wall board, gypsum			#115		0.13
-Rock wool					#140		0.045
-Plywood					#207		0.09
-vapour barrier, plastic, PVC	#122		0.001
-Rock wool					#140		0.17
-Bitumen, impregnated fibreboard	#123	0.13
-Air gap						#96	
-Face brick, block_m_sw.clay	#79		0.105
total thickness							0.671
				
Kind regards,
Wimolsiri

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Wimolsiri Pridasawas
Royal Institute of Technology
Department of Energy Technology
Division of Applied Thermodynamics and Refrigeration
Brinellvägen 60
SE-100 44 Stockholm
Sweden

Phone: +46 (0)8 790 8941
Fax: +46 (0)8 20 30 07
Email: wimol at energy.kth.se