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Main >> Applications >> Sample problems >> Thermal bridges in building construction. Test case 3 validation
QuickField validation of the test case A.3 presented in ISO 10211:2007 Thermal bridges in building construction.
Problem Type:
3D problem of heat transfer.
Geometry:
all length units are in millimeters.
Given:
Thermal conductivity of AAC λ_{1} = 0.7 W/K·m.
Thermal conductivity of insulation λ_{2} = 0.04 W/K·m.
Thermal conductivity of brick λ_{3} = 1.0 W/K·m.
Thermal conductivity of concrete slab λ_{4} = 2.5 W/K·m.
Thermal conductivity of plaster λ_{5} = 1 W/K·m.
Problem:
The floor slab penetrates the wall near the corner and forms the cold bridge. Determine the flux and the thermal coupling coefficients.
Solution:
Air contact surface thermal resistance R_{s} is caused by the convection. The convection coefficient value is reciprocal to the surface resistance value:
α = 1 / R_{s} [W/(K·m^{2})].
Results:
Temperature distribution in media (click to see 3D view):
Temperature in the corners: 
QuickField 
Reference 
%% 
First floor 
11.12°C 
11.11°C 
<0.1 K 
Second floor 
11.37°C 
11.32°C 
<0.1 K 
Heat flux: 
59.4 W 
59.98 W 
1% 
Thermal coupling coefficients (reference values are in the brackets).
External 
First floor 
Second floor 

External 
(1.000) 
(0.000) 
(0.000) 
First floor 
0.375 (0.378) 
0.401 (0.399) 
0.223 (0.223) 
Second floor 
0.329 (0.331) 
0.216 (0.214) 
0.455 (0.455) 
To comply with the ISO 10211:2007 the difference between calculated and reference heat flux should be less than 2% (0.1°K  for temperature). This simulation accuracy complies with the requirements of ISO 10211:2007.
Download simulation files (files may be viewed using any QuickField Edition).
*ISO 10211:2007(en) Thermal bridges in building construction  Heat flows and surface temperatures  Detailed calculations.