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Documentation and Online-Help

Please feel free to download a demo version of the program! This demo version contains only a small material data base, saving and printing of projects is not possible. An english version is in preparation!

For this software exists an extensive Online-Help and documentation of the physical theory (unfortunately only in German so far).

This program is permanently extended and improved, therefore single illustrations in the help-file may differ from the current version. However, the basic functionality of the program remains the same. The use of this program is - at least we hope so - intuitive and easy to learn.

 

Physical Theory

The calculation algorithm of the COND software is too complex to be illustrated extensively here. The master thesis with a complete description of the basic principles is enclosed to the installation-CD or the downloaded demo-version respectively.

However, a short description of the theoretical basics will be given here.

Basic principle

Starting from a vapour permeable construction, that can consist of many layers, the one-dimensional and stationary heat and moisture transport is observed. On both sides of the construction, the climatic conditions are constant. The climate is described by temperature und relative humidity at each side of the construction.

The gradient of temperature results in heat flow through the construction. After a certain time a stationary heat flow is reached. This stationary heat flow and the profile of the temperature that follows from it, can be calculated.

The gradient of vapour pressure results in a vapour flow through the construction. Here again, a stationary vapour flow is reached after a certain time. The stationary vapour flow and the profile of the vapour pressure, that follows from it, can be calculated as well. If the calculated vapour pressure exceeds the saturated vapour pressure (which is directly dependent on the temperature), condensation occurs inside the construction.

As soon as condensation water accumulates in the construction, it is distributed from the condensation area, thus resulting in liquid fluxes in addition to the vapour fluxes. (Annotation: this is the essential enhancement in comparison to the Glaserscheme, which disregards capillary liquid water transport).

Now, a global condition of equilibrium is assumed, i. e. the inward diffusion of vapour flux into the construction is equivalent to the outward diffusion of vapour flux. Furthermore, a local equilibrium is held in the stationary state, that is determined by the combined liquid water and vapour flux and is as large as the stationary (global) vapour flux.

These conditions of equilibrium can be characterised through various equations. The solution of the generated system of equations is the distribution of moisture in the stationary condition.

Through consideration of the time-dependent transient phenomenon, an estimation of the expected distribution of moisture can be made, that is to be expected due to condensation after a specific period of time.

 
 

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