Update archive

WUFI Pro, version (as of 08 February 2013):

  • WUFI
The new WUFI version has version number 5.2.

In addition to the existing automatic grid generator, now called “Automatic (I)”, the user can now also select a new grid generator “Automatic (II)” which distributes the grid elements across the assembly in a more efficient way.

In addition to the pre-defined fineness settings Coarse/Medium/Fine, the user can now specify an arbitrary number of grid elements (up to 1500) to be distributed across the assembly. In particular, this allows much more elements than the previous upper limit of 100.

Since for realistic simulations of flat roofs and other non-vertical components the long-wave radiation exchange with the sky must often be taken into account quantitatively, WUFI now warns the user if the inclination of the component is less than 90° but the option “Explicit Radiation Balance” is not activated.

Before introduction of the “explicit radiation balance” option in version 4.1, WUFI automatically switched to a “simplified radiation cooling” mode when a climate file with TRY format was used. Now this mode is not automatically activated any more because the option “explicit radiation balance” is recommended for all cases which require overcooling effects to be taken into account. The user can re-acticvate this mode (for example, to reproduce older simulations) in the climate dialog “Detailed Options” (it will then be used for all climate formats which contain counterradiation data, not only *.TRY files).

If a material has no moisture storage function defined (i.e. the relevant table is empty), WUFI always uses an internally pre-defined default moisture storage function instead. Previously, the graphical diagram showing the moisture storage function remained empty in these cases, which could mislead the user to think that no moisture storage function was used for this material. Now the default moisture storage function being used is displayed in these cases (in light green, while the user-defined curves are dark green).

For mathematical reasons, a moisture storage function must always be an ascending function. WUFI now checks at the start of a calculation whether the tabulated values of all moisture storage functions are ascending and issues an error if it finds a table which is not ascending.

The user can now choose whether heat transfer across the surfaces is to be described by heat transfer coefficients or heat transfer resistances (which are the reciprocals of the coefficients). This option can be found in the dialog “Options | Unit System…”.

When the optional wind-dependent heat transfer coefficient (or resistance) is activated, the user can now edit the model parameters of the wind-dependence.

The list of pre-defined short-wave absorptivities now includes generic “bright” and “dark” surfaces (a = 0.2 and 0.8, respectively), and various types of architectural titanium-zinc sheets.

There is now a drop-down list offering a few predefined ground short-wave reflectivities.

The drop-down lists in the dialog “Surface Transfer Coefficients” now pop up a tool tip showing the coefficient value corresponding to the list entry over which the cursor is hovering.

A moisture source can be used for imposing an additional moisture load on the component in order to assess its drying reserve. If a pre-defined amount of moisture is to be deposited in the component during a pre-defined period of time, the user previously had to compute the required source strength and to create a file controlling the time-dependent behavior of the source. The new moisture source option “Constant Monthly Moisture Load” now does this automatically. The user only has to specify the total amount of moisture to be deposited per year (e.g. the 250 g/m2 required by standard DIN 68800 for wooden roofs) and the months during which the deposition shall take place.

The climate analysis now also displays the yearly counterradiation sum, the mean cloud index and the mean wind speed (if present in the weather file).

In previous versions, the results of a climate analysis were lost when the user switched to a different dialog; upon return to the analyser dialog, the analyser had to be run again in order to show the analysis results. The dialog now keeps the results.

In order to process the weather data correctly, WUFI needs to know the geographical coordinates, the elevation and the time zone of the respective location. However, in certain weather file formats, and occasionally in user-defined files, some of these data are missing. Any missing data need to be supplied by the user via a so-called AGD file (*.AGD). Previously, these files had to be created by hand. Now, if WUFI finds that some of these data are missing in the selected weather file, it asks the user and automatically creates an AGD file containing the user input. (This feature may be considered as an “AGD editor”.)

Following recent changes in US standard ASHRAE 160 on which WUFI’s “ASHRAE 160” indoor climate model is based, the following changes have been made in the model in order to remain compatible with the standard in its current version:
The following limiting rule has been added to section 4.3 of the standard: “Indoor design humidity shall not exceed 70% RH.”
Table 4.3.2 has been modified in the following way:

Table 4.3.2 Residential Design Moisture Generation Rates
 Number of Bedrooms   Number of Occupants
Moisture Generation Rate
1 bedroom 2 8 7 L/day 0.9 0.8 x 10-4 kg/s 0.7 0.64 lb/h
2 bedrooms 3 12 9 L/day 1.4 1.0 x 10-4 kg/s 1.1 0.83 lb/h
3 bedrooms 4  14 10 L/day  1.6 1.2 x 10-4 kg/s  1.3 0.92 lb/h
4 bedrooms 5 15 11 L/day 1.7 1.3 x 10-4 kg/s 1.4 1.0 lb/h
Additional bedrooms +1 per bedroom +1 L/day +0.1 x 10-4 kg/s +0.1 lb/h

Because of incorrect processing of the time column, WUFI could not use multi-year files in DWD-TRY format. This bug has been fixed.

The dialog “status of last calculation” has been slightly rearranged and expanded. It now also shows the start and end date of the calculation. The “Number of Rain Absorption Failures” is not meaningful any more due to changes made in the calculation procedure in a previous version and has been removed.

The quick graphs can now also be accessed via the menu bar (menu “Outputs”), not only via the project tree.

To aid interpretation, the quick graphs displaying the water contents of the individual layers can now show a reference line at a user-specified water content (in mass-%). A right-click on the diagram opens a context menu with the menu item “Ref.line…”. Enter “20”, for example, to draw a reference line at 20 mass-% which is a critical water content for wood. Enter “-1” to remove the reference line. (A reference line can only be added if it is within the y-axis range displayed by the automantic axis scaling.)

A y-axis in mass-% can optionally be displayed at the right side of the quick graphs showing the water contents of the individual layers. In the new version, this can still be done, but the left y-axis can now be switched to mass-% as well.

The automatic axis subdivisions of the quick graphs now look more pleasing.

The result graphs (including user-defined graphs) can now be incorporated into the report (they are off by default, however, and must explicitly be activated in the report “Options”).

For the ASCII export, the user can now specify the number format, the column separator, the date/time format (or consecutive numbering) and optionally a header line explaining the content of the columns (in the dialog “Options | Export Format…”).

The visual appearance of the databases has been polished.

Previously, only either the German, the English or the Japanese online help file was installed, depending on the language selected for the installation process. Switching WUFI to a different language later (using WUFI5_Lan.exe in the Tools folder) did not change the online help file.
Now all three language versions of the online help file are installed, and changing WUFI’s language will also switch between the online help languages (German help file for German WUFI, Japanese help file for Japanese-English WUFI, and English help file for all the other language settings).

The Thermal Transmission post processor now also has a German language version.

Previously, the language selected for the installation process also determined which one of the maps for selecting climate files was the default map. Now the user can select the default map during installation.

[08 February 2013]

WUFI 2D, version (new installation package with unchanged WUFI2D-3.3.exe, as of 08. Feb 2013):

  • WUFI 2D
In addition to the updated database (see below), the installation package now contains an updated version of the graphical result analysis program WUFI-Graph.

[08 Feb 2013]

Material database update for all WUFI versions (as of 08 Feb 2013):

  • Material database
    Version DB24.76
The following 46 materials have been added:

  • Source: Fraunhofer IBP:
    • Catalog: Mortar and Plaster:

       Knauf Rotkalk Fein,  Knauf Rotkalk Grund

    • Catalog: Insulating Materials:
       GUTEX Thermoroom,  HOMATHERM ID-Q11 standard,  HOMATHERN USD-Q11 protect,
       HOMATHERM EnergiePlus comfort,  HOMATHERM EnergiePlus massive,  thermalan iso /swisswool iso /tirolwool iso,
       ISOCELL Zellulosedämmstoff,  Hanf-Kalk-Dämmung,  Pavaflex,
       isofloc L,  ISOVER GW Integra ZKF-032,  ISOVER GW Integra ZKF-035,
       ISOVER GW Integra ZSF-032,  ISOVER INTEGRA AP Supra-035,  ISOVER ULTIMATE Klemmfilz-035,
       AGEPAN UDP N+F,  Dennert Mineralschaumplatte,  Aspen Aerogels – Spaceloft Grey,
       Misapor 10/50, lastabtr. Wärmedä. unter Gründungsplatten,
       Misapor 10/50, lastabtr. Wärmedä., feuchtegeschützt und Innenbereich,
       Misapor 10/75, lastabtr. Wärmedä. unter Gründungsplatten,
       Misapor 10/75, lastabtr. Wärmedä., feuchtegeschützt und Innenbereich,
    • Catalog: Wooden Materials; Boards:

       KLH Massivholz,  AGEPAN OSB/3 PUR, 12 mm,  AGEPAN OSB/4 PUR, 12 mm

  • Source: Generic Materials:
    • Catalog: Air Layers:

       13 new air layers

  • Source: Japan Datenbase (new!):

     Dailite MS 9 mm,  Dailite MS 12 mm

  • Source: Materials for thermal calculations (from DIN 4108-4 or other sources):
    • Catalog: IBP Measurements:


[08 Feb 2013]
  • Weather Data
315 new weather files with hygrothermally critical years for the U.S. and Canada have been registered in the database (three files for each of 59 previously registered and for 46 new locations). The weather files themselves are not included with WUFI; if you need them, just download them separately and copy them into WUFI’s Climate folder.

[08 Feb 2013]

WUFI Pro, version (as of 25 January 2011):

  • WUFI
The new WUFI version has version number 5.1.

It is now possible to integrate post processors for evaluating and assessing the hygrothermal simulation results provided by WUFI. A postprocessor for assessing the thermal transmission through the component is included. An example postprocessor demonstrating the integration into WUFI can be downloaded from our website (documentation and instructions are included).

In the computation of solar radiation on an inclined surface, the radiation reflected from the ground has been taken into account in the “Explicit radiation balance” mode, but not in the standard mode. It is now always taken into accocunt (except, of course, for horizontal surfaces).
The input box for the “Ground Short-Wave Reflectivity” is displayed in the dialog “Surface Transfer Coefficients” after clicking the button “Details”. It is always used, however, independent of whether explicit radiation balance is activated or not.

For materials using the default moisture storage function, initial moisture contents above free saturation resulted in initial relative humidities above 100%. In this case, too, relative humidity will now be limited to 100%.

The XML files used for importing and exporting material data can now use both <CR><LF> or <LF> as end-of-line characters.

[25 Januar 2011]

Material database update for all WUFI versions (as of 14 Sep 2010):

  • Material database
    version DB24.70
An interior insulation system (Sto) and a rendering system (Baumit/Bayosan) have been added to the database.

[14 Sep 2010]

WUFI 2D, Version (as of 15 July 2010):
(The changes made to the database apply to all WUFI versions. The installation packages of the other WUFI versions have been updated accordingly.)

  • WUFI 2D
The material data dialog of the database editor (Database | Materials… | New or Change) now has a button for importing material data.

#102, #195
The geometry dialog serves to build the component from rectangles, which may not overlap however. When the user tries to create an overlapping rectangle via the script editor, the error message displayed in the status bar will now tell with which existing rectangle the new one did collide.

The short-wave absorptivity, the long-wave emissivity and the sd-value of the currently edited surface can be entered by the user or selected from lists of predefined values. A selection from a list fills the respective text box with the selected value, but this text box used to remain editable. However, an edit made by the user will usually result in the edited value being inconsistent with the selected descriptor in the list. So the text boxes are now disabled when a value is selected from the list and are only re-enabled when ‘user-defined’ is selected.

When liquid transport coefficients were generated from the A-value, an A-value greater than 1 resulted in erroneous coefficients which were not visible in the material data table, but were passed on to the calculation kernel, resulting in unrealistic behavior of the affected material. A-values greater than 1 kg/m²√s will not occur in practice, but a few materials in the database had them because of an inaccurate data conversion.
The wrong A-values in the database have been corrected, the limit imposed on the A-value has been raised to 1E6.

When specifying the surface transfer conditions for vapor transport, the user can choose between entering the vapor transfer coefficient beta or the sd-value. When the entered value is passed on to the calculation kernel, it is given a negative sign (but further processing is done with the positive value, of course) if it is to interpreted as the beta. A positive sign indicates it is the sd-value.
However, if the user entered beta=0 in order to simulate a vapor-tight surface, the value -0 was passed on which is the same as +0 and was therefore interpreted as sd=0, resulting in the reverse of the intended effect.
If the user enters beta=0, a very small but finite negative number is now passed to the kernel.

The time-dependent source strengths of the heat and moisture sources may be derived from the climatic boundary conditions. However, when the boundary condition is set to ‘adiabatic’, any climate data associated with it are ignored and the resulting source strenghts are zero. The user now receives a warning when trying to derive the source strength from a boundary condition set to adiabatic.

The time-dependent source strengths of the heat and moisture sources may be derived from climatic boundary conditions or read from text files. It could happen that a source insisted on being associated with a boundary condition even though it had been instructed to read its source strength from a text file. This has been corrected.

#187, #194
When a material was edited and the edits included a change to the name, it could happen that after saving and re-loading of the project the assembly contained the old material again.
This was due to the fact that a new XML file was created for the edited material, under the new name. If then the project was saved to a directory which contained an earlier version of the project, most of the old files were overwritten by their newer versions. But, because of its new name, the XML file with the new material did not overwrite the old material file (with the old name), so that both were present in the directory. Since WUFI-2D did not identify the files by their name but by an ID number contained in the files, and because this ID was the same in both material files, WUFI-2D could not distinguish the two files, read the alphabetically earlier file, and in some cases thus read the obsolete file instead of the current one.
Now WUFI-2D first looks for a file with the correct name and only falls back to consulting the ID when the search for the file name fails. The obsolete file still exists but doesn’t interfere any more with this process. It disappears if the project is saved with the activated option ‘clear project directory before saving’ (accessible in Options | Settings… | File).

If, while a calculation was running, the project data were saved under a new name via “Save Project As…”, a newly started calculation still created a result file with the old name, as long as the ‘processing’ dialog had not been exited meanwhile.
This was due to the fact that the data (including the project name) are passed to the calculation kernel via a transfer file INPUT.DAT which is created when the ‘processing’ dialog is opened. As long as this dialog is not exited, no new INPUT.DAT is created which might reflect the change made to the project name.
In order to avoid these inconsistencies, all the file operations in the ‘File’ menu are now blocked during a calculation.

When reading a project file, WUFI-2D copies the files from the project directory to the cache directory and from there reads the data into memory. Usually WUFI-2D is working on the data held in memory and only writes them back to the cache directory when the user wants to save the project or explicitly forces a write with CTRL+W. The latter option can be used to create a snapshot of the current state of the project, which can later be read again into memory with CTRL+R or File | Revert to last cached, providing a rudimentary undo function.
However, when a material is edited with the material editor, this editor (being a little stand-alone program) exchanges the edited data with the preprocessor via a data file written to the cache file. Thus, the old material data were overwritten and could not be recovered with CTRL+R any more. Now the data are exchanged via a temporary file with a different name, so that the old data are available until overwritten by the next CTRL+W.

An attempt to save a project to a path with insufficient free space could result in data loss. Now WUFI-2D checks for available space and, if necessary, issues a warning which gives the user the chance to change to a different save path (if available) or to free up some disk space.

When a material or boundary condition assigned to the assembly was unassigned, it could happen that the confirmation query popped up under the allocation dialog and thus was not accessible, completely blocking WUFI-2D. This bug has been fixed.

When reading a *.WAC file where the number of columns specified in the header lines is different from the actual number of columns, it could happen that WUFI-2D issued a “range check error” and stopped reading. This unintended behavior is now intercepted.

The database editor is offered in the start menu, but it refused to run because it expected some command line parameters. This problem has been fixed.

The user-specific INI file for WUFI-2D may now contain separate sections for different WUFI-2D versions. It is thus possible to have several operational WUFI-2D versions on one PC. In particular, these sections may contain the path to the calculation kernel, so that each version automatically calls its appropriate kernel version.

A possible error message when attempting to save (“Could not save…”) is now avoided by checking for the existence of a result file before attempting to move it to the project directory.

An error message “SetPixelFormat failed” which was triggered by some Windows versions is now avoided, because the Windows function for determining the pixel formats supported by the computer has been replaced by a homemade routine.

Some typos have been fixed, a few texts have been reformulated, and several cosmetic changes have been applied.

[15 Jul 2010]
  • WUFI 2D
    calculation kernel
When the field of initial water contents was read from a file, those materials which have no moisture storage function of their own (but instead use the internally predefined default moisture storage function) could be filled with wrong water contents. This bug has been fixed.

When the initial temperature, relative humidity or water content fields are read from a file, some interpolation must be performed if those fields are defined on a different grid than the grid currently used for the calculation. This interpolation has been revised in order to avoid interpolating across material boundaries. Close to a material boundary, the field existing within the material is now extrapolated towards the material boundary. This is necessary because the water contents may be strongly discontinuous at material boundaries. An interpolation scheme might cause high local moisture contents to inappropriately ‘seep’ into dry neighboring materials.

If fields of initial values are read from a file but are defined on a grid which is smaller than the current calculation grid, some grid elements will remain undefined. These elements are automatically filled with standard values (water contents: zero, temperature and relative humidity: average component temperature and humidity). This allows the user to view the current state of the project without error messages constantly popping up.

File names had originally been limited to 90 characters. For users preferring long file names or working in deep directory structures with long path names, this could result in truncated file names, rendering WUFI-2D unable to find climate files or result files. This has been fixed.

The 64 bit compilation of the calculation kernel is also available as a version which allows to distribute a WUFI-2D calculation across several computers working in parallel. It can be supplied on request.

[15 Jul 2010]
  • WUFI2DMotion
Several new predefined schemes for the color legend have been included:

  • DewpointRiskIndoor.leg
    (Temperatures between 10°C and 14°C are highlighted to indicate the possibility of the temperature falling below dew point level)
  • FrostDamageRisk.leg
    (Temperatures between -5°C and +1°C are highlighted to indicate the possibility of frost damage)
  • RH80Risk.leg, RH90Risk.leg, RH95Risk.leg, RH98Risk.leg
    (Relative humidities between 80% (or 90%, 95%, 98%) and 100% are highlighted to indicate the possibility of mold growth)

These color schemes can be found in the directory Projects\Samples\; right-click on the color legend in WUFI2DMotion to import them.

The temperature, moisture etc. fields resulting from the calculation can now also be displayed with the material boundaries of the component superimposed. Right-click on the respective film window to open the context menu and switch ‘material borders‘ to ‘visible‘.

WUFI2DMotion usually starts with a standard view. User settings, such as a rotated view or a zoom setting are thus lost and must tediously be re-created after each start of WUFI2DMotion.
However, the user can write the settings (window position, zoom factor, rotation, color legends etc.) to an INI file by pressing CTRL+W, and restore them at any time by pressing CTRL+L.

The material data may now be displayed by the film viewer, too. “View | Material data” opens a separate window which lists the data of the material under the mouse pointer.

If desired, the background colors of the film windows may now be changed by the user. A click on the color legend title opens a color dialog; the original background colors are available as predefined custom colors.

In film windows displaying fluxes, color schemes can now be defined for the vector arrows. This allows, for example, to recognize the intensity of the flux even if all arrows are shown normalized to the same standard length. Right-click on the color legend to open a context menu which allows you specify the desired number of colors, the color scheme etc., just like with the other film windows.

The arrows visualizing the fluxes may now be thinned out to make the display less crowded. Open the context menu with a right-click on the film window and enter a threshold value between 0 and 1 in the menu item drawing mode | threshold. When an arrow is to be drawn, WUFI2DMotion then generates a random number between 0 and 1 and only draws the arrow if this number is below the threshold. For example, when a threshold of 0.1 has been specified, only one tenth of the arrows will be drawn. (The option is only available when all arrows are normalized to the same standard length.)

For each computed quantity (temperature, relative humidity, …) WUFI-2D computes one representative value for each element of the computational grid. The user can read out this value by pointing the cursor at the desired grid element in the film window: the corresponding value will be displayed in the lower right corner of the film window.
Up to now, the displayed value would change slightly in dependence of the position of the cursor within the element, because it was interpolated between this and the neighboring elements. Furthermore, the displayed value depended on the zoom level. Now one fixed, unambiguous value will be displayed for the entire grid element.

If the option ‘linearize colors’ is active for the color legend, WUFI2DMotion will create a linear color gradient between the first and the last color. However, the user may still edit the colors in between (with ‘linearize’ active, the neighboring colors will automatically be adapted; with ‘linearize’ not active, they won’t).
When such a user-edited color legend with active ‘linearize’ option was exported and re-imported, the execution of the saved ‘linearize’ command caused the colors to be interpolated again between the first and the last legend entry, and the customized colors in-between to be overwritten. Now the import function suppresses any ‘linearize’ option saved with the legend.

The film displayed wrong values at the corners of a component. This bug has been fixed.

Depending on the decimal separator specified in the regional settings, it could happen that a color legend was imported incompletely. Because of the floating-point type used for the legend, rounding errors could occur. These bugs have been fixed.

The interpolation used to smooth the color fields for display now relies on a homemade routine instead of the OpenGL function used previously, and thus produces more satisfying results.

WUFI2DMotion now displays its version number in the “About” dialog.

A few typos have been fixed.

[15 Jul 2010]
  • Material database
    version DB24.68
The ‘Limestone’ from the Generic North-American Database was renamed ‘Limestone (Georgian Bay Limestone)’ in order to avoid confusion with other limestones which may have completely different properties.
Furthermore, the last two entries in the moisture storage function of this limestone were too small by a factor of ten and have been corrected accordingly (to 32.5 instead of 3.25 kg/m³, and to 34 instead of 3.4 kg/m³).
(Although the corrected moisture storage function faithfully reproduces the data given in the relevant source, it should be noted that this moisture storage function (with zero values up to 70.3% RH) and the mu value (with its strong decrease for humidities above 90% RH) may not be unconditionally suitable for hygrothermal simulations.)

For the insulation material “Dämmstatt’s CI 040”, an additional value has been inserted in the moisture storage function for a relative humidity of 97%, in order to describe the hygric behavior at high humidities more reliably. (After consultation with the manufacturers, the same value as for isofloc has been used.)
For tabulating the amended moisture storage function, a new three-point function had to be fitted to the data. In addition, the redistribution coefficients which are derived from a drying experiment (with the derivation being dependent on the moisture storage function) had to be determined anew.

[15 Jul 2010]
  • Installation
The database editor WUFI_DBEditor.exe is now installed in the Tools directory in order to facilitate its future maintenance in the course of database updates.

A faulty installation of the tools which are needed for distributing a WUFI-2D calculation over several computers working in parallel prevented them from working properly. This has been fixed.

[15 Jul 2010]

WUFI Pro, Version (new installation file with unchanged WUFI.exe, as of 12 May 2010):

  • Material database
    version DB24.67.0.0
The material database can now also be switched to Italian or Czech language. For the time being, Krakow serves as the default climate location for Czechia.

Several products of the Roxul company have been added to the material database.

A gypsum board with PCM additive has been added to the material database.

The “Solid Brick Bernhard” had a wrong µ value of 159 instead of the correct 19. This has been fixed.

For some of the recently added “Air Layers without additional moisture capacity” the free saturation exceeded the maximum saturation determined by the porosity, thus provoking an error message. This has been corrected.

The A-values for the materials “Mud Plaster” and “Mineral Sgraffito Plaster” (imported from the MASEA database) had been entered with erroneous values. This has been fixed.

[12 May 2010]
  • Weather Data
14 weather files for locations in New Zealand have been added.

In the Portuguese translation the name for the “Oceania” map was missing, so that this map did not appear in the drop-down list and thus could not be selected. This has been fixed.

[12 May 2010]
  • Installation
In the example project file “Example_USA.w5p” the exterior heat transfer resistance 0.0588 m²K/W had inadvertently been replaced by the inverse value (the heat transfer coefficient 17 W/m²K). This has been fixed.

The option for language selection at the start of the installation did not offer a Polish installation when the PC did not have the proper language support. It is now always offered, independent of the computer configuration.

[12 May 2010]

WUFI Pro, Version (as of 10 March 2010):

  • WUFI
WUFI may now also be switched to Portuguese language.

The film viewer Animation1D can display several films in parallel. When additional film windows were opened, it could happen that these windows remained empty and failed to display film data. A tweak of the timing settings has reduced the occurrence of the problem but may not have eliminated it completely.

The measured data which can be imported for display together with the calculation results are saved in the project file along with all the other project data. In the last version they were inadvertently dropped from the list of data to be saved. This has been fixed.

If a *.WAC weather file is to be used for calculations with explicit radiation balance it must contain a column ILAH (atmospheric counterradiation on a horizontal receiving plane) or a column ILM (total long-wave radiation as incident on the building component under investigation). If such file contains a column ILM but no column ILAH, then ILM should of course be used.
WUFI did that correctly, but it also erroneously issued a warning claiming that the file contains no counterradiation data and the longwave irradiation has to be estimated from the cloud cover. This baseless warning has been removed.

Due to a programming error wrong water contents may result for non-capillary materials (e.g. mineral wool) lying at the component surface, if these are saturated with water (e.g. because of condensation) and at the same time exposed to rain. This has been fixed.

[10 Märch 2010]
  • Material database
The effective thermal conductivity for the 70 mm thick air layers was wrong by a factor 10 (0.04 instead of 0.4 W/mK). This has been corrected.

[10 Märch 2010]

WUFI 2D, Version (as of 18 February 2010):

  • WUFI 2D
Besides the cartesian grid geometry for plane wall assemblies that has been used exclusively up to now, the new version of WUFI 2D also allows assemblies with radial symmetry. This broadens WUFI’s scope to objects like thermal bridges, condensation on wall anchors etc.
The left side of the assembly is taken as the inner side of a hollow cylinder, the assembly itself defines the structure of the cylinder wall, and the right side of the assembly corresponds to the outer side of the cylinder. The inner radius R0 is specified in the ‘Computational Parameters’, the outer radius is the sum of the inner radius and the width of the assembly. (The distance of the assembly from the y-axis in the graphical display of the assembly only serves for convenient visualisation and does not indicate the inner radius.)
An inner radius ≤ 0 will switch to the usual cartesian treatment of the assembly.

Material data can now be imported und exported via XML files for easier data exchange.
In order to import material data, the user first has to create an empty material. To do this, open the dialog “Allocation of properties” which is used for allocating material data to the individual elements of the component, open the material database with the button “New” and close the database dialog with the “Close” button without selecting any material. The working list of the allocation dialog now contains an empty “material” which can be filled with manually edited or with imported data.

WUFI 2D can now use materials with temperature-dependent heat capacity. Possible applications include wall assemblies which contain phase change materials (PCM) for thermal regulation.

If needed, the temperature-dependence of the thermal conductivity can now also be accounted for. An approximation method permits to allow for the temperature-dependence in an approximative way if no more detailed data are available.

In addition to the usual measured thermal conductivity, commercial products listed in the material database may now also have a design value for the thermal conductivity which may be used for design purposes.

The table used for specifiying constant initial temperatures or water contents for individual materials now also allows to automatically assign the same value to several materials with one click: press <Ctrl>+<Enter> to assign the value in the highlighted table cell to all the lower cells in the same column.

The initial state of the temperature and the moisture field can now also be read from a file. This allows to continue a finished calculation by using its final state as the initial state of the new calculation. The moisture field can optionally be given in terms of water contents or relative humidities.
Use the film viewer WUFI2DMotion to export a temperature or moisture field into such a file: “Goto” the desired point in time and right-click into the temperature or water content or relative humidity field to open a pop-up menu offering the menu item “extract | initial conditions”.

WUFI 2D now determines the disk space required for the calculation results before starting the calculation and issues a warning if there is not enough free space.

The display of the elapsed CPU time for times beyond 99999.99 seconds has been fixed.

When heat sources and moisture sources had been associated with the same boundary conditions, the sources which were not the first to be assigned lost their association. This has been fixed.

In the boundary conditions dialog, the user can choose between a constant and a wind-dependent heat transfer coefficient. However, if the weather file specified for the calculation has no data on wind speed, then the constant coefficient must be used, regardless of user choice. In this case, the coefficient actually used for the calculation was not visible to the user because the content of the edit field for the constant coefficient was blanked out. The content of this field now remains visible and editable.

In the boundary conditions dialog, the user can choose to describe the vapor transfer across the surface in terms of an sd-value or a vapor transfer coefficient. However, when the option “Treat as Inner Surface” was selected, re-opening the dialog caused the value of the vapor transfer coefficient to be overwritten with the sd-value. This has been fixed.

Before saving a project (that is, copying the files from the cache directory to the project directory), the user had to make sure that the cache directory was synchronised with the working data residing in RAM (by pressing <Ctrl>+W). Otherwise, it could happen that the cache directory was not up to date on the current editing status and the most recent edits could be lost. WUFI 2D itself now automtically performs the synchronisation before saving a project.

During saving of a project it could happen that some necessary file operations, such as renaming the result file etc., failed because the result file was still in use by WUFI 2D or one of the result viewers (WUFI2DMotion, WUFIGraph). This could lead to inconsistencies. Now WUFI 2D explicitly tests whether there is any open file and, if so, prompts the user to close the file before saving.

After saving a project (with “Save Project” or “Save Project As…”) the file *.WFD containing the calculation results is now automatically deleted, in order to avoid inconsistencies resulting from future saving of the same file together with possibly changed input data. The results can still be viewed and analysed because WUFI accesses the result data now residing in the project directory (where the saving process has moved them).
If “Save Project As…” is used and the user selects the option not to save the result file, then the result file will be kept in the cache directory.

Occasional program crashes when switching between automatic and manual grid generation have been fixed.

When the minimum or maximum allowed number of grid elements was edited by the user, the changed values were saved in the project file, but they were not displayed when the project was re-opened. This has been fixed.

When for the interior climate model “ASHRAE 160” a different “Air Conditioning Type” than “Heating Only” was selected, the diagrams in the dialog showed the change correctly, but the calculation always used “Heating Only”. This has been fixed.

When during installation of WUFI 2D a file “WUFI2D-3.3.ini” from an earlier installation was found, the new installation took from it the path to the calculation kernel, but this path did not point to the current kernel when the new installation was done in a different directory. This has been fixed.

Under Windows Vista, closing WUFI 2D left an active process in memory. Furthermore, the online help did not work. Both problems were fixed by an update to the online help system.

[18 Feb 2010]
  • WUFI 2D
    calculation kernel
A 64 bit version of the calculation kernel has been included in the distribution files. It can address more memory than the 4 GB managed by the 32 bit version and thus allows larger grids. (There is only a minor increase in computation speed.)
This 64 bit kernel resides in the directory ‘x64’; it can be selected in the menu item “Options | Settings | File”.

The calculation kernel has been revised to include the functions necessary for the calculation features added to the new WUFI 2D version, such as radial symmetry, temperature-dependent thermal conductivity, temperature-dependent enthalpy etc.

An error in the mathematical treatment of the boundary conditions at re-entrant corners has been fixed.

The WUFI 2D variant created for use on parallel computers had ceased to work because a format change of the data exchanged between the preprocessor and the kernel had not been taken into account. This error has been fixed.

When water imbibition experiments are simulated, the originally used minimum number of four rain iterations can be reduced. The stop criterion has been reformulated so that a smaller number of rain iterations may be performed unless more are actually needed.

A change in the treatment of parameters passed to the program in batch mode, caused by use of a different compiler, could lead to program crashes. Parameter treatment has been adapted to the new compiler.

[18 Feb 2010]
  • WUFI2DMotion
In the film viewer, the GOTO function allows the user to jump to a later point in the film without needing to play all the film until that point. Due to an integer overflow, no later points than hour 28273 could be accessed in that way. This problem has been fixed.

[18 Feb 2010]

WUFI Pro, Version (as of 11. November 2009):
(See also the short version.)

  • WUFI
Besides the cartesian grid geometry for plane wall assemblies that has been used exclusively up to now, WUFI 5.0 also allows assemblies with radial symmetry. This broadens WUFI’s scope to objects like insulated cooling pipes or similar geometries.

WUFI 5.0 can use materials with temperature-dependent heat capacity. Possible applications include wall assemblies which contain phase change materials (PCM) for thermal regulation.

If needed, the temperature-dependence of the thermal conductivity can now also be accounted for (in addition to the moisture-dependence which has been a feature ever since WUFI’s inception). An approximation method permits to allow for the temperature-dependence in an approximative way if no more detailed data are available.

In addition to the usual measured thermal conductivity, commercial products listed in the material database may now also have a design value for the thermal conductivity which may be used for design purposes.

A new optional calculation mode switches the thermal conductivities of all materials to their design values. (If a material has no design value, appropriate alternative reference values are determined from the existing material data).

The calculation of the U-value has been amended to use alternative reference values (where needed) in exactly the same way as in the previous item.

For purely thermal calculations without moisture transport, WUFI now only requires the basic material data bulk density, thermal capacity and thermal conductivity. The edit fields for porosity and diffusion resistance factor may remain empty.

For this reason, the material database now also accepts materials for which only bulk density, thermal capacity and thermal conductivity have been specified.

Materials taken from the material database are initially read-only and have to be unlocked for editing. This makes it easier to distinguish original and edited data.

Material data can now be imported and exported for easier data exchange (in SI as well as in IP units).

The option to shift a weather file’s air temperatures by a user-editable constant amount (as suggested by standard DIN EN 15026) allows to expose building components to harsher conditions even if the original weather data represent typical average conditions.

A moisture source in the wall may now be controlled by a new infiltration model which describes the amount of moisture appearing there because of exchange with the indoor air.

The computational problems created when a moisture source’s output overwhelms the local absorption capacity of the wall material can now be avoided by specifying an appropriate user-selectable maximum water content. The amount of water by which the source had to be reduced in order to comply with the prescribed limit is reported in the calculation results.

The new XML-based project file structure will facilitate backward compatibility with future program versions.

If desired, pictures for documentation can be added to the project.

For the commercial products contained in the material database product images, company logos and weblinks can be displayed.

The result data exported to an ASCII file may now optionally be separated by tabulators instead of the usual spaces.

The WUFI versions Light and ORNL now can only open project files written by the respective version.

WUFI 5.0 may now also be switched to Italian or Spanish language.

The quantities xsat, Rvap, T0 occurring during the calculation are now computed more precisely.

Several minor bugs and inconsistencies have been fixed:
Reading *.EPW weather files now also works when the decimal separator specified in the computer’s regional settings is the decimal comma instead of the decimal point used in the *.EPW files.
Reading a *.WAC file could occasionally fail because a header line was not correctly recognized due to a character set problem. This problem has been fixed.
A (practically insignificant) typo in the barometric formula for converting the barometric pressure at sea level to the pressure at station height has been fixed.
In the material data dialog the table for the approximation parameters got messed up when the user switched to another component layer from within the dialog. This has been fixed.
The occasional program crashes that could happen when very large project files were being written should not occur any more because new writing routines handling the new XML format have been introduced.
The U- and R-values displayed in the assembly dialog were not updated when the user switched to a different project case. This has been fixed.

[11 Nov 2009]
  • Material database
Materials from the building materials database MASEA and the materials listed in the standard DIN 4108-4 have been added to the material database. (The latter have no hygric data except the μ value. The user must decide case by case whether they can be used in a hygrothermal calculation.)

[11 Nov 2009]
  • Weather data
    (WUFI Pro only)
The list of included international weather files now also comprises Wellington (New Zealand), Buenos Aires (Argentina), Santiago de Chile (Chile), Bolzano, Modena and Turin (Italy, further Italian weather files will follow).

In addition to the 1986 test reference years for the former West Germany which had been included since version 4.2, WUFI now also includes the new (2004) test reference years issued by the German Weather Service for the whole federal territory and their extreme summer and winter versions.

[11 Nov 2009]

WUFI 2D, version (as of 08 May 2009):

  • WUFI 2D
Several general bugs have been corrected (typos, crashs, rounding issues when transferring data to the calculation kernel etc).

WUFI 2D now allows to create heat, moisture and air change sources in the component.

The new option “Explicit Radiation Balance” allows to explicitly account for all short- and long-wave radiation fluxes at the exterior surface (if the selected climate file contains sufficiently detailed information about these radiation components).

Numerically problematic cases will benefit from the new adaptive time step control.

After the calculation, the user can now view a convergence analysis which will assist him in choosing appropriate numerical parameters such as residuum weights (new, see below), convergence criteria, iteration limits etc.

[08 May 2009]
  • WUFI 2D
    calculation kernel
The calculation kernel, too, has been upgraded with functions for processing the new heat, moisture and air change sources, the explicit radiation balance and the adaptive time step control.

An error affecting the treatment of the grid elements at the component surfaces has been corrected.

An error affecting the averaging of material properties at the material interfaces has been corrected (the interpolation cofficients for the two sides had to be interchanged).

The source code for the calculation kernel (mainly numerical parameters, internal constants etc.) has generally been revised to further improve agreement with WUFI 1D. The one-dimensional results of the two now agree almost completely. The sum (over all n grid elements) of the squared differences 1/n·∑ (result 1D – result 2D)² remains below 1·E-9 for the temperature field and below 1·E-7 for the humidity field, only calculations with rain absorption yield somewhat larger differences because of different algorithms (but remain below 1·E-3).

The relative weighting of the residuals of the temperature and moisture fields (which are used for iteration control during the calculation) can now be adjusted by the user. Experienced users may find this useful for improving iteration speed or for treating numerical problems.

For NTFS file systems (introduced with Windows NT4), use of a new compiler now eliminates the previous 2 GB limit for the result files. Splitting large result files, which sometimes caused file name problems, is no longer necessary. For FAT and FAT32 file systems the new limit is 4 GB.

On newer processors, the new compiler also allows parallel execution of loops with independent variables.

[08 May 2009]
  • WUFI2DMotion
The improved color legend allows the color gradient to be interpolated between more than two colors.

[08 May 2009]
  • WUFIGraph
The visualization tool WUFIGraph, written in Java, is now included as an EXE file (previously: JAR). It has been configured to automatically check for a compatible Java version and to install one if needed (requires an internet connection since the installation file must be downloaded from the Sun server for licensing reasons).

The isoline diagrams now have a reset button which rotates them back into their initial orientation.

[08 May 2009]

WUFI material database 24.46 (as of 30 March 2009):

  • Material database
An update release of the material database has been added to the installation packages (which remain unchanged otherwise).

Among other things, a wrong A-value for the insulation material “isofloc L” has been corrected (0.1069 kg/m2s0.5 replaces 6.4 kg/m2h0.5).

[30 March 2009]

WUFI Pro Version (as of 06 August 2008):
(download an update flyer illustrating the new features)

  • WUFI
WUFI’s language can now be switched to Swedish.

WUFI can now read Energy Plus weather files *.EPW (WUFI Pro only). Those files are available for a large number of locations and can be downloaded for free at http://www.eere.energy.gov/buildings/energyplus/. Please note that they do not contain precipitation data and thus cannot be used for investigations where rain is a crucial factor.

An Adaptive Time Step Control feature has been implemented in WUFI, in order to improve convergence behavior in numerically problematic situations.

The online help has been migrated to the HTML-based help system and is thus now available under Windows Vista, too. (The contents of the online help have not yet been updated to reflect the new features of WUFI 4.2; this will be fixed by an update.)

The component assembly dialog now automatically displays the R-value and the U-value of the assembly.

When WUFI detects unusual input data, it issues a warning but continues if the user chooses to ignore the warning. This feature should help to avoid some common mistakes while still allowing computational experiments.

For easier further processing, the quick graphs and the film screen can now be exported to the clipboard.

The color of the data points in the isopleth diagrams now changes from yellow (at the start of the calculation) to black (at the end of the calculation) to give the user some information about the behavior of the hygrothermal state in time.

A constant air change rate for an air change source can now directly be specified, without the need to create an input file with identically repeating hourly values (WUFI Pro only).

Several minor bugs and inconsistencies have been fixed. The computation of the reflected atmospheric counterradiation on inclined surfaces has been corrected.
The default interior climate is now “EN 15026” instead of the sine curves. When a material read from the database is about to overwrite a layer thickness already specified in the assembly, the user is now prompted for confirmation.

[06 Aug 2008]
  • Material database
Twenty generic materials from Sweden have been added to the database (source Lund University LTH).

The materials isofloc L insulation, Getifix mineral insulation board ambio and Redstone mineral insulation board Pura have been added to the database (source IBP).

[06 Aug 2008]
  • Weather data
    (WUFI Pro only)
12 Swedish weather files (Lund, Borlänge, Kiruna, Luleå, Umeå, Östersund, Karlstad, Stockholm, Norrköpping, Göteborg, Visby, Växjö), the 12 test reference years (1986) of the German National Meteorological Service for the former West Germany, and three Spanish weather files (Madrid, Barcelona, Bilbao; Malaga und Palma de Mallorca are in preparation) have been added.

For the location Holzkirchen, WUFI now also offers a representative Moisture Reference Year (including longwave atmospheric counterradiation).

[06 Aug 2008]

WUFI Pro Version (as of 28 March 2007):

  • WUFI
When a project contained several variants, the sources and sinks assigned to a variant could erroneously be associated with a different variant. This bug has been fixed.

[28 Mär 2007]
  • U-Value-Tool
Because of a change in the project file format of WUFI 4.1 , version of the U-Value Tool could not correctly read project files computed and saved by the current WUFI version, resulting in erroneous output. In the new version this bug has been fixed.

[28 Mär 2007]

WUFI Pro Version (as of 8 February 2007):

  • WUFI
In WUFI the absorbed amounts of driving rain were too low if time steps less than 1 hour were used. This has been fixed.

Heat, moisture and ventilation sources (or sinks) can now be added to the assembly (PRO version only). The source strengths can be controlled via an external file or can be made to depend on the exterior boundary conditions.

At the exterior surface, the full short- and long-wave radiation balance can now optionally be taken into account. One benefit of this is that nighttime radiative cooling and its hygrothermal effects can now be computed quantitatively.

The following models specified by ASHRAE Standard 160P (Approved Draft July 2006) have been implemented:

  • In addition to previous methods, the interior climate can now also be derived from the exterior climate via to the Standard’s “Intermediate Method”.
  • In addition to the previous method, the driving rain load can now also be determined via the Standard’s rain exposure factor and rain deposition factor (fixed factors in the ORNL version, user-editable factors in the PRO version).
  • A moisture source can be placed within the assembly in order to allow for diffuse rain penetration, expressed as percentage of the incident driving rain (e.g. 1%).

The calculation results now comprise additional curves showing

  • all radiation components
  • heat and moisture fluxes between all layers
  • source strengths of the heat and moisture sources
  • heat and vapor transfer coefficients at both surfaces
  • vapor pressure at the monitoring positions
  • barometric pressure
[8 Feb 2007]
  • Material database
Eight generic vapor retarders with sd-values between 1 m and 100 m, a vapor barrier with sd = 1500 m and three house wraps with sd-values between 0.1 m and 0.5 m have been added to the material database (source IBP).
Four generic vapor retarders with permeances between 0.1 and 10 perm have been added to the Generic North-American Database.

[8 Feb 2007]
  • Weather data
Several new climate files have been added to the PRO version:

  • Austria: Vienna, Graz, Innsbruck
  • Poland: Warsaw, Krakow, Kolobrzeg
  • Japan: Sapporo, Akita, Niigata, Tokyo, Yokohama, Naha, Miyazaki
[8 Nov 2005]

WUFI Pro Version (as of 8 November 2005):

  • WUFI
In WUFI the driving rain load was three times too high when IP units were used. This has been fixed.

In WUFI the Dewpoint Temperature in the Quick Graphs was always shown in °C even if IP units had been selected. This has been fixed.

The results for the monitoring positions in the Quick Graphs can now be viewed either as Temperature/Relative Humidity or as Temperature/Dewpoint.

All old *.KLI files can be used again now in the Pro version. Because of an error in the reading routine, WUFI only accepted *.KLI files beginning on January 1 and having a special date format.

The summary now contains detailed information on the climates selected for the left and right side of the component.

WUFI can now be run automatically as a batch job. For details please refer to the online help.

Creating user-defined climate files is made easier by the Excel spreadsheet CreateClimateFile.xls which can be found in the Tools folder.

[8 Nov 2005]
In addition to the applicable items above:

The membranes and air layers in the material database can now be accessed again. They have been assigned to the data source “Generic Materials”.

[8 Nov 2005]
  • Material database
Two new materials have been added to the database (Source IBP):

  • Isover Vario KM Duplex (catalog Membranes)
  • Pavatex Diffutherm wood fibre board (catalog Wooden Materials; Boards)
[8 Nov 2005]
  • Weather data
Four new climate locations have been added, each with a warm and a cold file: Calgary, Ottawa, Quebec and St. John’s. The climate files for Vancouver have been updated. The standard years for Winnipeg and Toronto have been replaced by one cold and one warm year each.

[8 Nov 2005]

WUFI Pro Version (as of 6 June 2005):

  • WUFI
WUFI can now read the new Test Reference Years published in 2004 by the German National Weather Service, as well as IWEC weather files (currently without rain, however).

Exterior and interior climate may now arbitrarily be assigned to the left or the right side of the building component (rain and solar radiation can still only be absorbed at the left side, however).

The revised climate module now makes it easy to use climate files from exterior sources.

The new climate analyzer gives an overview of the most important characteristics of the selected climate data.

The interior climate may now be derived from the exterior climate, using the models given in DIN EN ISO 13788 and PrEN 15026.

The new film viewer offers improved display of the films (e.g. single step forward and backward, zoom, etc.). The current values in each grid element can be scanned with the mouse pointer, their evolution in time can be exported to an ASCII file. The film itself can be exported to AVI format.

The new Quick Graphs allow a quick overview of the calculation results: total water content and water content in individual layers, temperature and dewpoint temperature at the monitoring positions, basic assessment of mold growth risk at the monitoring positions.

[6 June 2005]
  • Material database
78 new materials have been added to the material database: 50 materials for the data source “Generic North American Database”, 15 materials for the data source “NTNU Norwegian University of Science and Technology”, and 12 wood-based materials and a membrane for the data source IBP.

[6 June 2005]
  • Weather data
The Pro version now comes with additional weather files: 12 Norwegian cities (Kristiansand, Oslo, Gardermoen, Bergen, Kise pa Hedmark, Roeros, Kristiansund, Trondheim, Vaernes, Mo i Rana, Tromsoe, Karasjok) and one French city (Grenoble).

[6 June 2005]

WUFI Pro Version (as of 15 June 2004):

  • WUFI
If needed, WUFI can estimate moisture storage functions, liquid transport coefficients and moisture-dependent thermal conductivities from certain related standard properties (such as the reference moisture content, the water absorption coefficient etc). Even if a given material does not make use of that feature, the database must have data fields reserved for these ‘optional parameters’. For some materials these unused fields had the default value 1, so that a user activating the estimation functions might be misled to think the displayed numbers were intentional and valid values. These data fields are now explicitly left empty.

For mathematical reasons WUFI assigns relative humidities between 100% and 101% to moisture contents between free and maximum saturation; see the discussion of the moisture storage function in the online help. So as not to perplex the user, any relative humidity exceeding 100% is now set to 100% in the film display and the ASCII output. This means that any numerical checking of the results must allow for the fact that when moisture contents above free saturation occur WUFI’s calculations internally use slightly different relative humidities and thus different vapour pressures than appears from the output data. Likewise, it is not possible in these cases to compute the water content from the relative humidity in a grid element.

The rain data in the weather files are rain rates [Ltr/m2h], not rain amounts [Ltr/m2]. In the case of hourly rain data, the same numerical values result in both cases, but with other time intervals the user must be aware of the difference. For example, if it has been raining for an hour at a constant rate of 1 Ltr/m2h, the entries for this time interval in a climate file with 0.1h steps must be 1 Ltr/m2h for each timestep, not 0.1 Ltr/m2. The units [Ltr/m2] displayed on the result graph “rain” were therefore wrong and have been corrected to [Ltr/m2h].

A heat transfer resistance of 0 m2K/W at the surfaces may result if the surface is in contact with another material (e.g. soil), and must therefore be accepted by the program. During the revision work for the last version, a superfluous test had been inserted that would not accept a zero in this place. This has been corrected.

Reading the initial conditions from a *.ini file did occasionally create an ‘access violation’. The probable cause for this has been corrected.

When the *.ini file specified by the user for the initial conditions was not found, WUFI remained silent and initialized the moisture or temperature field with zeros. Now an explicit “file not found” error message is produced in this case.

Comments for the individual materials in the database and for the weather files can now be longer than 255 characters. This has no effect on the current release, but it is now possible to include detailed notes about the data sources. This information will be added in future releases.

WUFI now includes language support for a French version.

A larger number of sample files is now included: one each with a country-specific construction for Germany, USA and Finland, and two (english) sample files demonstrating the use of *.KLI weather files and *.INI initial condition files, respectively.

The dialog “About WUFI” now displays the WUFI version and the database version.

[15 June 2004]
  • Material database
The material data for gypsum plaster and gypsum board are practically identical. In fact, the data for the “interior plaster (gypsum plaster)” were originally measured on a gypsum board. A copy of this data set has now been added to the database under the name “gypsum board” to have both materials appear explicitly in the database.

The former “gypsum board” (from an American data source) has been renamed “gypsum board (USA)”. The moisture storage function was too high and has been corrected.

The thermal conductivity of the vinyl wall paper has been changed from 23 to 112 W/mK in order to have the complete dataset consistently converted to an effective thickness of 1 mm. Of course, with these thin membranes the actual value of the thermal conductivity has no appreciable effect on the thermal behaviour anyway…

[15 June 2004]

WUFI Pro Version (as of 16. February 2004):

  • WUFI
WUFI now comes with weather data for Lisbon. Select this weather location from the new weather map “South West Europe”.

A generic weather file USER.TRY in test reference year format has been registered in the database. In order to use your own weather data with WUFI, convert them into test reference year format (see format specification in the on-line help), name the file USER.TRY and copy it into WUFI’s climate folder. When, upon starting, WUFI finds such a file in this folder, it displays a dot in the upper left corner of the weather map for “Central Europe” where you can select it for a calculation. The coordinates of the location of measurement (needed for calculating the solar radiation incident on the surface of the building component) are taken from the file; the time zone, however (needed for the same purpose) is not specified in a TRY format file, so it must be taken from the corresponding entry in WUFI’s database. Currently this entry cannot be edited by the user; it has been set to the Greenwich time zone.

You can do a calculation for locations in other time zones by replacing the real geographic longitude of the location with a fictitious longitude that has the same distance from 0° as the real longitude from the reference meridian of the real time zone.
For example, the fictitious longitude of Sydney (latitude 33.95° south, longitude 151.18° east, time zone +10h) would be 1.18° E, since Sydney is 1.18° east of the reference meridian 10*15° = 150° of the Australian Eastern Standard Time zone. The relevant line in the header of the TRY file would be:
  LAGE: 33.95 GRAD S.<- B. 1.18 GRAD O. <- L. 0003 METER UEBER NN
On the other hand, the longitude 144.83° of Melbourne is west of the reference meridian, and the fictitious coordinates would be
  LAGE: 37.67 GRAD S.<- B. 5.17 GRAD W. <- L. 0141 METER UEBER NN
Latitudes and longitudes are to be entered without sign; the hemisphere indicators are: North = N, South = S, East = O or E, West = W.

(The ‘Exterior Climate’ dialog will display 0° as latitude and longitude when the user-defined location is selected, since at that time WUFI does not yet know the coordinates specified in the TRY file.)

Technical improvements:
WUFI now uses a dynamical language system, so that one single program file contains both the German and the English version; the language to be used is selected at the beginning of the installation.
WUFI now uses a new script-based and multilingual installer.

[16 Februar 2004]
  • Material database
The FERMACELL Gypsum-Fibreboard has been added to the material database.

The PE membranes with sd-values of 2 m and 5 m have been replaced by a generic vapour retarder with an sd-value of 3.3 m (= 1 perm).

A PE membrane with an sd-value of 50 m has been added to the material database.

The MFD board has been removed from the database.

The material data for the spun bonded polyolefin have been revised and updated using ASHRAE material data, since the table for the moisture-dependent µ-value contained an error (false: µ(0%)=40, µ(100%)=406.36; corrected: µ=const=43).

The material data for the 60 minute Building Paper have been converted to correspond to an effective membrane thickness of 1 mm to be consistent with all the other membranes in the database.

The material data of the Vinyl Wall Paper have been revised and updated using ASHRAE material data, since the table for the moisture-dependent µ-value contained an error (false: µ(0%)=200, µ(100%)=197.7 for d=0.45 mm; corrected: exponential function 3060 .. 342 for deff=1 mm).

The American Asphalt-impregnated paper has been added to the database (using ASHRAE material data).

[16 February 2004]

Polish Version

  • WUFI
A Polish version of WUFI 3.3 Research & Education is now offered for download.

[06 February 2004]

WUFI Pro Version (as of 7 November 2003):

  • WUFI
Occasionally, convergence failures may occur during a calculation. In most cases they are caused by very strong coupling between heat and moisture transport, e.g. in very permeable materials (such as mineral wool) at high temperatures. Because of intense evaporation and condensation phenomena the temperature and moisture fields then interact strongly. The newly introduced convergence improvement linearizes the thermal and hygric source terms that are responsible for the coupling and thus reduces convergence problems.

The input routine reading the test reference year files has been revised to accept numbers in which some of the trailing decimals required by the FORTRAN format specification have been replaced by blanks (e.g. ‘14.07’ -> ‘14.1 ‘ or ‘14.07’ -> ’14 ‘). While these numbers violate the strict format specification, there is no reason why WUFI shouldn’t read them nevertheless. Creating files in this format is thus made simpler: trailing zeros can now be omitted, as is usually done by most tools or writing routines.

The material data include capillary transport coefficients: one table each for the processes of suction and redistribution. If the table for redistribution had been left empty, WUFI used to apply the table for suction instead, applying thus suction values to redistribution processes. This behaviour has been changed and WUFI now strictly uses the values from the redistribution table for the redistribution process, assigning zeros to the coefficients if the table is empty. This is usually not much more realistic than before, but it strictly follows the input of the user. If the user wants to have redistribution processes simulated, he must supply the relevant material data.
The slag cement in the material database had such an empty redistribution table and has temporarily been removed from the material database.

[7 November 2003]

WUFI Pro Version (as of 24 February 2003):

  • WUFI
When switching between SI and IP units, the conversion of the µ-value (SI) to the permeability (IP) and vice versa resulted in the reciprocal of the correct value, due to a bug in the conversion routine. This did not affect calculations performed in SI mode. Calculations in IP mode were not affected either if materials from the database were used. Since the permeability of the materials in the database had been computed incorrectly, too, and WUFI internally converts all data back to SI units for the calculation, the error was made twice and the calculation result was correct although the wrong permeability value was displayed in the material data dialog. A problem occurred with materials entered by the user, as the internal conversion of their permeability was incorrect.
The conversion routine and the wrong data in the database were corrected. The installation routine of the corrected WUFI now scans an existing database (if any) for user entries and offers the option to correct the entries in the database if necessary. For entries that were made with previous WUFI versions the SI and IP values for the µ-value and the permeability, respectively, are inconsistent with each other as one of them was entered by the user and the other one computed by WUFI using the faulty conversion routine. The installation routine detects these cases and asks the user which of the conflicting entries is the correct one.

The Canadian weather files contained too much rain and were corrected.

Weather files were added for Baltimore, MD, Little Rock, AR, Spokane, WA, Providence, RI, Casper, WY, Fargo, ND, International Falls MN.

The material names and catalog assignments in the database have been revised and cleaned up.

A few details were added to the online help.

[24 February 2003]

WUFI Pro Version 1.3.1.x (as of 18 October 2002).

  • WUFI
The iteration algorithm for rain absorption has been revised. This should almost completely eliminate rain absorption failures (which usually are harmless anyway).

In general, the transport coefficients for grid element boundaries are determined from those for the neighboring grid centers by computing the harmonic mean if the neighboring elements contain different materials, and by computing the arithmetical mean if the neighboring elements contain the same material. The liquid transport coefficients are an exception; they are computed as arithmetical means.
However, until now liquid transport coefficients were always tested for whether the coefficient of at least one of the neighboring materials was zero. If so, the coefficient for the element boundary was also set to zero (“pseudoharmonic”). This test has been removed now, so that the liquid transport coefficients are always and unconditionally computed as an arithmetic mean. This allows water that may accumulate in an insulation layer due to condensation to be taken up by a neighboring capillary-active material. Originally this was not possible, since the liquid transport across the material boundary had been set to zero if (as is usually the case) the insulation material was not capillary-active and thus had its liquid transport coefficients set to zero.

When the user wanted WUFI to read initial conditions from a file but left the edit field for the file name empty, WUFI would unspecifically complain about an “I/O error 6”. The new error message “File “” does not exist” may be slightly more helpful.

When the component assembly was copied from an existing variant, the selected option for the grid fineness was not included in the copied data. This has been corrected.

If the user sets the surface heat resistance to zero m²K/W, WUFI must prevent the internally used heat transfer coefficient (which is the reciprocal of the surface heat resistance) from becoming infinite by using a large but finite value instead. In order to avoid numerical problems, this replacement value has been reduced from 1e30 to 1e8.

The new version number is 3.3.

[18 October 2002]
  • Material database
The following new materials have been added to the database:
PE-Membrane (Poly; sd-value 5 m),
Wood Shavings,
Flax Insulation Board,
Wood-Fibre Insulation Board,
Lime Plaster (demineralization),
Demineralisation Compress,
Mineral Insulation Board,
Cellular Glass,
Oriented Strand Board,
MFD Board.

[18 October 2002]
  • Climate Generator
The climate generator dialog has now a minimizing icon.

When a *.KLI file is being generated from a *.WET file and one of the ground temperature channels has been selected as the source for the temperature data (i.e. the KLI file is meant for a component in contact with surrounding soil, e.g. a cellar wall), rain and radiation are now automatically set to zero; the relative humidity is set to a constant value entered by the user.

[18 October 2002]

WUFI Pro Version 1.2.5.x (as of 18 October 2001).

  • WUFI
The version counter in the updated material database was not set correctly, preventing the WUFI installer from updating the databases of earlier WUFI versions. This has been fixed.

[30 October 2001]

The new version is now called WUFI 3.2, accordingly it will be installed in the installation path WUFI32.

The German WUFI version now has a German on-line help.

The following new materials have been added to the material database:
a water-repellent exterior rendering system, concrete blocks with pumice aggregate, 2 kinds of highly insulating aerated clay bricks, expanded clay brick, fired clay brick (used for cellars), cellulose fiber insulation, wood shavings and flax mats.

The North-American climate data are now included with the German Pro version, too.

All WUFI versions now include Swiss climate data (Zurich, Davos, Locarno, one ‘cold’ and one ‘warm’ year for each) and climate data for Kassel.

On the climate map, the climate locations are now represented by dots with different colors, depending on the type of the corresponding climate file. Furthermore, a dot now only appears if the corresponding climate file (as registered in the database) does exist in the climate folder.

A bug in the computation of the exterior vapor diffusion thickness (continuous accumulation of the vapor diffusion thickness when a wind-dependent heat transfer resistance was selected) has been corrected.

The screen display of WUFI is designed for a screen resolution of 1024 x 768 pixels. As a consequence, on screens with lower resolution (e.g. notebooks), parts of the dialogs could not be reached; scrollbars have now been added to avoid this problem.

When data were copied from one variant to another, little inconsistencies could occur concerning the copied exterior and interior climate data; this has been fixed.

If another inclination than 90° is selected for the component, WUFI now defaults to rain coefficients R1=1 and R2=0. In this case the user himself has to provide appropriate coefficients, because the situation with inclined components is too complex to be cast into a simple multiple-choice option list.

The computation of the harmonic mean for the material parameters at layer interfaces has been slightly modified.

The design of the dialogs “Options: Result Data” and “Result Graphs: Image Options” has been revised.

Several misspellings in the dialogs have been corrected.

[18 October 2001]
  • Climate Generator
On the climate map, the climate locations are now represented by dots with different colors, depending on the type of the corresponding climate file. Furthermore, a dot now only appears if the corresponding climate file (as registered in the database) does exist in the climate folder.

[18 October 2001]

WUFI Pro Version 1.1.4.x (as of 12 June 2001):

  • WUFI
The new WUFI version comes with weather files for Switzerland (Zurich, Davos and Locarno, with a warm and a cold year for each) and for 53 North American cities (49 USA, 4 Canada): the Swiss files are distributed with WUFI-pro 3.0 and WUFI 3.0 R&E, the North-American files only with WUFI-pro 3.0 in the English version.

A modification of the iteration algorithm reduces the number of convergence failures markedly.

The default temperature for the interior climate has been set to the correct 21 +-1 °C.

Bugs concerning saving and reading of files have been eliminated, a few minor corrections have been applied overall.

[12 Juni 2001]
  • WUFI database
The newest version of the database is available for download (performs an update of the existing database; custom entries by the user remain untouched, of course).

In particular, new weather data from Switzerland and North America have been registered in the database. The weather files themselves are distributed with the updated WUFI installation packages.
[12 Juni 2001]

  • WUFI database
IBP now also offers the material database independently of WUFI for general purposes. The database file for download contains a database viewer.
[12 Juni 2001]
  • Climate generator
The climate generator has been updated to remove bugs concerning units of barometric pressure, reading geographical coordinates from weather files, saving files from the editor and deleting data rows in the editor. When generating from WET file, the generator now also accepts other coordinates than those of Holzkirchen, so that weather data from other locations can be used in WET format, too. A button ‘Clear all’ has been added to the editor.
The climate editor is also offered separately for download.
[12 Juni 2001]

  • WUFI 2D
When the user selected the option to generate the liquid transport coefficients Dw (suction or redistribution) from the moisture storage function and the A-value instead of using the tabulated values, WUFI erroneously only did so when the table was empty. When the table was not empty, WUFI continued to use the tabulated values instead but indicated it was generating the data. This was no problem with the materials provided in the database since there the table is empty for all materials for which the Dw are generated by default. However, it was a problem when a user entered some data into the table but then decided to have the values generated. Bug has been fixed.

It has been reported that in some cases where sine waves were selected as boundary conditions, these selections had somehow been altered after some editing had been done in other dialogs. We were not able to reproduce this behavior, but a few changes were made to the program that are expected to fix it. Reports about any reoccurrence of the problem would be welcome.

[18 July 2002]