Software / WUFI / Demo films
Watch how to perform a calculation in WUFI with a few mouse clicks.
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The demo film shows how to prepare, perform and analyse the simulation of an ETICS with WUFI Pro.
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The demo film shows how to set up and start a WUFI 2D simulation of a vertical section through a wall/ceiling corner with exterior insulation.
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The demo film shows how to analyse the results of a WUFI 2D simulation with the graphics tool WUFIGraph.
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The "boundary conditions" describing the ambient thermal and hygric conditions acting on the component are usually expressed in terms of meteorological data (such as air temperature, relative humidity etc). These data are often provided by weather files containing hourly weather data which have been measured at or simulated for a specific geographical location. There are numerous different weather file formats which may use different physical quantities to describe the same boundary conditions (e.g. relative humidity or water vapor partial pressure or wet bulb temperature to describe the moisture content of the air).
Furthermore, thermal radiation (emitted by the sun and by surrounding surfaces) and precipitation (driving rain) are directional quantities whose impact on the surface in question depends on its orientation and inclination. Sometimes these directional quantities have been directly measured on the surface to be modeled and can be used by WUFI without further modification. Usually, however, no such direct measurements are available and the radiation and rain components incident on the surface must be computed from other measurements, usually made on horizontal surfaces.
WUFI's *.WAC format for weather files has been designed to accomodate a wide variety of physical or meteorological input quantities
and to offer flexibility in using directional quantities. WUFI itself will do the necessary physical or directional conversions, if
needed.
In order to compute the solar radiation incident on any surface from data measured on a horizontal surface, WUFI needs
the diffuse and the direct or the global radiation on the horizontal surface, the geographical coordinates and the time zone.
In order to compute the rain incident on any surface, WUFI needs the normal rain (i.e the rain measured on a horizontal
surface), the wind speed and the wind direction
In order to assist the user in creating a *.WAC file, the Excel sheet CreateClimateFile.xls
is provided with WUFI (in the Tools folder). The user only needs to copy the hourly data
into the columns of the spreadsheet and to select an appropriate description for each column. A click on a button then
starts the export the data to a *.WAC file.
The following demo films show some possible choices of input data for a *.WAC file. It is assumed that the user has
already acquired the respective data and is ready to copy & paste them into the spreadsheet. The columns may be entered
in any order.
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For an indoor climate file only indoor temperature and humidity are needed. In this example, we are even satisfied with using constant climate values, so the columns in the spreadsheet may simply be filled by pasting the same values to the entire row range or by using Excel's autofill feature. |
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An outdoor climate file is created for a west-facing vertical surface, using solar radiation and rain data measured directly on the
surface in question. In this case, no standard radiation or rain data (i.e. measured on a horizontal surface) are needed, and WUFI does not need to perform any directional conversion. WUFI's calculation results are not affected by possible shortcomings of the conversion models, but the weather file can only be used for surfaces with the same orientation and inclination. |
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An outdoor climate file usable for arbitrary surfaces is created, using global and diffuse solar radiation measured on a horizontal
surface and letting WUFI convert these standard radiation data for the orientation and inclination of the surface to be modeled. No rain data are involved in this example. If hourly data for the air pressure are provided, the altitude of the location need not be specified. |
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An outdoor climate file usable for arbitrary surfaces is created, letting WUFI compute the solar radiation and the rain
impacting on the specific surface under investigation from standard meteorological data.
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In building physics, the long-wave radiation exchange between the facade and the surroundings is usually not considered explicitly but allowed for by an appropriate increase on the heat transfer coefficient.
For a more accurate computation of surface temperatures, WUFI can be switched to an "Explicit Radiation Balance" mode where all short-wave
and long-wave radiation components are explicitly taken into account.
Of course, the user must then provide sufficient data on all these radiation components. If needed, WUFI can convert short- and long-wave
radiation data measured on a horizontal surface for the surface under investigation, and it can estimate long-wave radiation data from
other weather data.
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In this example, the user provides global and diffuse solar radiation data measured on a horizontal surface (letting
WUFI do the conversion on the surface under investigation) and long-wave data measured directly on the surface in question (avoiding
the need for WUFI to convert those data).
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Here, the user has no long-wave radiation data measured directly on the surface in question and must let WUFI estimate the
long-wave radiation incident on the surface from standard data measured on a horizontal surface. To do this conversion,
WUFI needs the atmospheric and the terrestrial counterradiation components on a horizontal surface.
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In this example, WUFI shall work in the 'explicit radiation balance' mode, but no data on atmospheric and terrestrial
long-wave counterradiation are available. WUFI can try to estimate the long-wave radiation from the air temperature
and humidity and the cloud index (i.e. the fraction of the sky covered by clouds). The atmospheric counterradiation is estimated from the air temperature and humidity and the cloud index. The terrestrial counterradiation is estimated by assuming that all terrestrial surroundings have air temperature and all have the terrestrial emissivity entered by the user in WUFI's "explicit radiation balance" dialog. Depending on the inclination of the surface under investigation, appropriate fractions of atmospheric and terrestrial counterradiation are then combined to yield the total long-wave counterradiation incident on the surface. |
