Known bugs

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WUFI® Pro 6.2

Interior climate model “User-editable text fields in the indoor climate dialogs require pressing ENTER before switching to a different project case.
  • Context:
    The user-editable text fields in the indoor climate dialogs do not require to press the ENTER
    key when editing is finished. When the user is done editing and selects a different edit field
    in the dialog, or a different branch of the project tree, an ENTER is automatically issued,
    confirming the input.
  • Bug:
    However, if a different project case is selected, no ENTER is issued and the unconfirmed input
    in the text field will be lost on switching away from the indoor climate dialog.
  • Workaround:
    Press the ENTER key before switching to a different case.

WUFI® Pro 6.0.2

Interior climate model “EN15026 /WTA 6-2” - resolved in WUFI® Pro 6.1:
Indoor temperatures resulting from options „Low Moisture Load“ and „Medium Moisture Load + 5%“ are too high.
  • Context:
    In this interior climate model the indoor temperature is derived from the outdoor temperature by means of a transfer function. For outdoor temperatures below 10°C the transfer function returns the indoor temperature 20°C, for outdoor temperatures above 20°C, the transfer function returns the indoor temperature 25°C. For outdoor temperatures between 10°C and 20°C the indoor temperature increases linearly from 20°C to 25°C.
  • Bug:
    Due to a faulty data transfer within the program, the indoor temperature starts increasing linearly at -10°C (instead of +10°C) if one of the two moisture load options mentioned above is selected. Therefore, the indoor temperatures resulting from the model are too high for outdoor temperatures between -10°C and +20°C. As a consequence of the temperatures being too high, the resulting moisture load is also too high.
    In the climate dialog, the transfer function and its tabulation are shown in the correct versions, it is therefore not evident to the user that internally a faulty transfer function is used instead.
  • Workaround:
    Use a different interior climate model or create the desired interior climate yourself (following the prescription of WTA 6-2, using e.g. Excel and the WUFI® tool CreateClimateFile, and writing the result to a WAC file).
Switching between SI and IP units - resolved in WUFI® Pro 6.1:
Converting a project saved in SI units to IP units fails to convert all input data if WUFI® is set to IP units when the project is opened.
  • Context:
    If the user intends to run a calculation in IP units, switches WUFI® to IP and opens a project which is in SI units, the project opens in SI units.
  • Bug:
    When WUFI® is subsequently switched back to IP units, some input data are not converted to IP (for example, the heat transfer coefficients; the material data are not affected). In the simulation run, WUFI® then assumes that all input data are in IP units, while some numerical values are still in SI units. This inconsistency may lead to incorrect calculation results.
Opening a project in a different language - resolved in WUFI® Pro 6.1:
Input data selected from a drop-down list may become replaced by a different item from the drop-down list.
  • Bug:
    If a project file is opened which had been saved in a different language than WUFI’s current language setting, some edit fields may contain wrong values.
    Due to an inconsistency in the language-dependent indexing of the entries in the drop-down lists (the alphabetical sorting of the entries in the drop-down list results in different sort sequences in different languages), it may happen that an edit field with a drop-down list displays a wrong entry from the list (which is then used in the calculation).
  • Workaround:
    Switch WUFI® to the language in which the project has been saved.
Wind-dependent heat transfer coefficient in calculation mode „explicit radiation balance“ - resolved in WUFI® Pro 6.1:
Changing the value for the radiative component from the default value causes wrong computation of the heat transfer coefficient.
  • Context:
    In its normal calculation mode, WUFI® uses heat transfer coefficients which contain a convective and a radiative component. In calculation mode „explicit radiation balance,“ the radiative heat exchange occurring at each time step is automatically determined and taken into account as part of the simulation itself. In this case, the radiative component must be removed from the heat transfer coefficient to prevent it from being counted twice. If a constant heat transfer coefficient is used, this means subtracting the value entered in the edit field „includes long-wave radiation parts…“. If a wind-dependent heat transfer coefficient is used, this means subtracting the radiative component αrad specified in the relevant dialog.
  • Bug:
    If a wind-dependent heat transfer coefficient is used, instead of subtracting αrad WUFI® erroneously subtracts the value in the edit field „includes…“. The default values in the two edit fields are the same, so that no error results as long as they are not changed by the user. However, if the user changes one of the two values, the wind-dependent heat transfer coefficient is first calculated using the value αrad, and then the different value in the edit field „includes…“ is subtracted instead of αrad.
  • Workaround:
    If a wind-dependent heat transfer coefficient is to be used in the calculation mode „explicit radiation balance,“ please make sure that the edit field „includes long-wave radiation parts…“ for a constant heat transfer coefficient contains the same number as the edit field arad for the wind-dependent heat transfer coefficient, because otherwise a wrong value will result for the wind-dependent heat transfer coefficient.
  • Note:
    You can always use the ASCII export feature to check the value used by WUFI® for the heat transfer coefficient.
Sources/Sinks:
A source in the outermost grid element may lead to wrong water contents.
  • Bug:
    In connection with rain absorption, sources placed in the outermost grid element at the surface of the assembly may cause numerical problems leading to unexpected moisture contents and balance problems.
  • Workaround:
    Do not place a source in the outermost grid element.
User-defined climate files in the user folder - resolved in WUFI® Pro 6.1:
User-supplied data are ignored if the climate file is not displayed on the climate map.
  • Context:
    For easier access, climate files provided by the user can be added to a user folder managed by WUFI. In some climate file formats, geographical data needed by WUFI® are missing (e.g. geographical coordinates or the time zone) which can then be entered in WUFI’s user folder list.
    For each file in the user folder an option „Show on map“ determines whether the respective file is displayed on the climate selection map.
  • Bug:
    If the option „Show on map“ is not checked for a file with user-added geographical data, these user-added data are not forwarded to the program.
  • Workaround:
    Check the option „Show on map“.
IP mode and climate selection - resolved in WUFI® Pro 6.1:
If WUFI is in IP mode by default, climate selection may fail.
  • Bug:
    If WUFI starts with IP units as default units, one of the necessary internal initialization routines is inadvertently skipped. As a result, switching between outdoor and indoor climate dialogs may not work properly, and WUFI may issue the error message „No climate file selected,“ even though a climate file has been selected by the user, or a climate option requiring no climate file has been selected.
    The problems do not occur if the current project has been read from a project file.
  • Workaround:
    We offer a patch file installing a corrected initialization routine. Please contact support@wufi.com.

WUFIGraph 2.13.2

  • Occasionally, very large projects can not be saved or reopened.

WUFI® Pro 5.3

  • The option to edit the numerical grid manually has inadvertently been dropped in WUFI® Pro 5.3; it is accessible again in WUFI® Pro 6.

WUFI® 2D 4.1

User-editable text fields in the indoor climate dialogs require pressing ENTER before switching to a different project case.
  • Context:
    The user-editable text fields in the indoor climate dialogs do not require to press the ENTER
    key when editing is finished. When the user is done editing and selects a different edit field
    in the dialog, or a different branch of the project tree, an ENTER is automatically issued,
    confirming the input.
  • Bug:
    However, if a different project case is selected, no ENTER is issued and the unconfirmed input
    in the text field will be lost on switching away from the indoor climate dialog.
  • Workaround:
    Press the ENTER key before switching to a different case.

WUFI® 2D 4.0

Result files with non-ASCII characters in the file name can not be opened with VisIt.
  • Context:
    Since version 4.0, WUFI® 2D writes the result files in the HDF format which can optionally be opened and analysed by the open source program VisIt. The name of the result file is automatically the name of the last folder in the path under which the project is saved. For example, if you save the project under the path “C:\WUFI2D\projects\wall”, then the result file will be named “wall.wfd”.
  • Bug:
    If the name of the result file contains a non-ASCII character (such as a German umlaut), VisIt
    can not open the file. (This is a limitation of VisIt over which we have no control.)
  • Workaround:
    Use only pure ASCII characters for the project folder and thus for the result file name.
Source strength files in the compressed hour format are read incorrectly (fixed in version 4.1)
  • Context:
    The source strength of a heat, moisture or air change source can be controlled by means of a source strength file which provides hourly data on the source strength, for example
     
    1           0
    2           0
    3           3e-8
    4           3e-8
    5           3e-8
    6           0
    …
     
    As an alternative to one line for each hour, the file may also use a compressed hour format. For example, the file
     
    1460     0
    3460     3e-8
    8760     0
     
    describes a moisture source which releases no moisture during the hours 0 through 1460, then releases
    moisture at a rate of 3e-8 kg/(m s) during hours 1461 through 3460, then becomes inactive again for
    hours 3461 through 8760.
  • Bug:
    Source strength files in this compressed hour format are read incorrectly, resulting in heat and moisture source strengths which are much too high.
  • Workaround:
    Use source strength files with one separate line for each hour.

WUFI® 2D 3.4.2

  • DXF import is only possible for files using meters [m] as length unit; importing files in [mm] or [cm] does not work.

WUFI® Plus 3.1.0.0

Bug in the report of DIN 4108-2
  • [Report] The values for natural ventilation during residence time and outer residence time are interchanged in the report “DIN 4108-2 Verification”. This error only appears in the report. The simulations use the correct ventilation rates.
    Resolved with version 3.1.1.

…coming soon…

Thermal Transmission 2.3.1

Post-processor „Thermal Transmission“ displays wrong R-values if user-defined monitors have been placed in the simulated component.
  • Context:
    If the post-processor “Thermal Transmission” is called up after a simulation run, it computes the effective R- and U-values of the component from WUFI’s hourly simulation results. WUFI transfers to the post-processor the heat flux density through the interior surface, the surface temperatures on both sides (for the R-value) and the air temperatures on both sides (for the U-value).
    During the simulation run, WUFI records the temperatures and humidities occurring at the locations of “monitors” which can be freely positioned within the component. A monitor is automatically placed on each of the two surfaces – these two monitors are providing the surface temperatures needed for the
    R-value.
  • Bug:
    For the R-value, WUFI is supposed to transfer to the post-processor the temperatures at the surfaces, that is, the temperatures at the first and the last monitor in the component. Instead, it transfers the temperatures at the first and the second monitor. If there are no other monitors in the component, the resulting R-value will be correct. However, if there are user-defined monitors in the component, temperatures from a point within the component will be transferred instead of the temperatures at the indoor surface and the resulting R-value will be incorrect.
  • Workaround:
    Please remove all user-defined monitors from the component.

WUFI® Database 26.0.82.0

Product “Securock® ExoAir® 430 System, Layer 1 of 2” in the North American database has incorrect values for the permeability.
You can download the corrected material data here until the next database update.

Last Update: November 23, 2021 at 14:26