AnTherm analyses temperature conditions in building components in which heat flows not just in one direction, but in two- and three-dimensional patterns. This is of critical interest when evaluating the thermal performance - an important design criteria - of so-called thermal bridges, that is, regions of a building construction through which local peaks of heat loss can cause surface temperatures to drop below the dewpoint.
Thermal heat bridges are characterized by multi-dimensional heat flow, and therefore by the fact that they cannot be adequately approximated by the one-dimensional models of calculation typically used in norms and standards for the thermal performance of buildings (U-values).
Surface moisture due to condensation (typically occurring in such regions as floor-wall connections, window installations, etc.) as well as mould growth in humid environments can also be effectively prevented by means of multi-dimensional evaluation during planning and detail design.
Importance of Thermal Heat Bridges in Civil Engineering
In new development the thermal optimization of junctions in today common low energy constructions receives very special standing. The subject of avoiding thermal bridges in passive houses became predominant.
During renovation one can significantly miss the target of heat energy savings if no or no attention has been paid to multidimensional heat flows incurred by thermal heat bridges. On the other hand thermally weak junction constructions easily lead to low interior surface temperatures, resulting in moisture and then followed with an outcome of mould growth. Not only comfort and the health value get significantly impaired but at the last resort structural damage shall result.
This is fundamental, that the impact of multidimensional heat transfer cannot be estimated by approximative methods which are available for manual calculation nor by any means predictable by "intuition" the help provided by computer applications which ensure sufficiently reliable planning is needed.
Parallel to the requirement of high precision, which shall be validated appropriately, the ease of use during the data entry and transparent interpretation of calculation results provided by proper evaluation tools are of the highest importance. By interntion such a "thermal heat bridges program" must allow 2- and 3-dimensional modeling to adhere to common requirements.
The thermal heat bridges program AnTherm perfectly satisfies all the named requirements.
Computational description of vapor diffusion in building constructions can provide valuable hints for answering the questions if there is a risk of, potentially destructive, vapor condensation within the construction (core condensation) or not. Diffusion equations have the same structure as those describing heat transfer and can be solved analytically only for one dimensional vapor diffusion. In all higher dimensional cases numerical methods, like the one implemented in AnTherm, have to be used.