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Hygric and Thermal Simulation

Thermal bridge simulation

The following example demonstrates how easily and efficiently HTflux can be used to calculate the energy loss of a thermal bridge. After importing the CAD data in DXF format (e.g. created with AutoCAD or ArchiCAD) you can assign the materials with few mouse clicks.  If you have created an import wizard you can even skip this point, as HTflux will assign the materials according to the names of your CAD layers.

With two further mouse clicks you can setup our powerful PSI measuring tool. This will not only display the PSI-value itself, but it will also enable you to display a whole lot of other information, such as the U-values of the two legs used for the calculation or even a table containing all the information of the construction layers. (see below)

After processiong the simulation, which usually takes only few seconds, you are able to switch between many possible views, such as object view, materials view, temperature, heat flux, relative humidity, partial pressure and water vapor stream. Also the position and value of the lowest or highest temperatures can be calculated and displayed automatically. With one click you can also display the condensation or mold threshold temperatures. If the surface temperature falls below the latter the humdity raises above 80% resulting in a significant risk of mold growth. A further value that can be displayed at any time is the temperature factor f*Rsi. This value is also used to assess the risk of mold, but is independent of the actual temperatures used for the simulation.

In our example below you can see that the thermal conductivity of concrete or even reinforced concrete should not be underestimated. The attic construction shows a strong thermal bridging effect. There is a heat loss of 0.4 watts per meter of construction and degree Celsisus. Assuming a temperature difference of 30 °C and a surrounding attic with a total length of 32 m would therefore cause a heat loss of approx. 400W.


Thermal Bridge - Temperatures

Thermal Bridge – Attic example – Temperature view

Thermal Bridge - Heat Flux

Thermal Bridge – Attic example – Heat Flux

Attic example - Materials View

Attic example – Materials View

Thermal Bridging - Heat Flux - Detail view

Thermal Bridge – Heat Flux – Detail view


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