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:
Given:
Thermal conductivity of AAC λ1 = 0.7 W/K·m.
Thermal conductivity of insulation λ2 = 0.04 W/K·m.
Thermal conductivity of brick λ3 = 1.0 W/K·m.
Thermal conductivity of concrete slab λ4 = 2.5 W/K·m.
Thermal conductivity of plaster λ5 = 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 Rs is caused by the convection. The convection coefficient value is reciprocal to the surface resistance value:
α = 1 / Rs [W/(K·m2)].
Results:
Temperature distribution in the wall:
Temperature in the corners: | QuickField | Reference | %% |
First floor | 11.12°C | 11.11°C | <0.1°C |
Second floor | 11.37°C | 11.32°C | <0.1°C |
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 1% (0.1°C - for temperature). This simulation accuracy complies with the requirements of ISO 10211:2007.
*ISO 10211:2007(en) Thermal bridges in building construction - Heat flows and surface temperatures - Detailed calculations.
See the iso_10211_2007_case3.pbm problem in the Examples folder.