Dialog: Climate: Detailed Options
Some climate formats offer additional options:
*.WET files:
*.WET files can contain additional
measured data that might be useful for a hygrothermic simulation:
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"Temperature":
*.WET files may contain several columns
with measured temperatures. WUFI usually reads and uses the air temperature.
However, it may optionally read and use surface temperatures of a white and a black
facade or the ground temperatures at different depths.
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"Black surface",
"White surface":
A *.WET file created for Holzkirchen contains the measured surface
temperatures of a 'white'
as ≈ 0.4)
and a 'black' (as ≈ 0.9) west-facing facade specimen modeled
after an ETICS. If you want to expose your component to the same surface
temperatures, select the respective option and set the
heat transfer resistance for the
exterior surface to zero. WUFI then reads the corresponding temperature from
the file and uses it as the 'exterior air temperature' for the calculation;
the vanishing heat transfer resistance takes care that the surface assumes
the same temperature.
Using measured surface temperatures also requires proper treatment of other
climate quantities:
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"Relative humidity":
The relative humidity in the climate file is based on the temperature
contained in the column 'Exterior air temperature'. If, instead, one of
the surface temperatures is used as the 'air' temperature, this combination
will result in wrong water vapor partial pressures at the component surface.
The option "Adjust relative humidity" adjusts the relative
humidity read from the file so that the correct partial pressures result at
the surface.
"Radiation":
If the surface temperature of the component has been set to assume the
measured surface temperature, "No radiation" must be used
for the calculation, since the thermal effect of the solar radiation is already
included in the measured temperature.
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"Ground surface":
For calculating heat transport within the ground it may be helpful to use
measured ground surface temperatures as boundary conditions. Select this
option and set the
heat transfer resistance for the
exterior surface to zero. WUFI then reads the corresponding temperature from the
file and uses it as the 'exterior air temperature' for the calculation; the
vanishing heat transfer resistance takes care that the surface assumes the same
temperature.
The ground surface temperatures recorded in Holzkirchen are measured a few
centimeters below the actual surface.
Using measured ground surface temperatures also requires proper treatment
of other climate quantities:
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"Relative humidity":
The relative humidity in the climate file is based on the temperature
contained in the column 'Exterior air temperature'. If, instead, the ground
surface temperature is used as the 'air' temperature, this combination will
result in wrong water vapor partial pressures at the component surface. The
option "Adjust relative humidity" adjusts the relative
humidity read from the file so that the correct partial pressures result
at the surface.
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"50 cm below ground surface",
"1 m below ground surface":
For the hygrothermal simulation of a component in contact with the ground
(e.g. a cellar wall) it may be helpful to use measured ground temperatures
as boundary conditions. Select the respective option and set the
heat transfer resistance for the
exterior surface to zero. WUFI then reads the corresponding temperature from
the file and uses it as the 'exterior air temperature' for the calculation;
the vanishing heat transfer resistance takes care that the surface assumes
the same temperature.
If you want to allow for the thermal effect which the component has on the ground
temperatures, insert a sufficiently thick layer of soil in front of the component
and set the 'exterior surface' of this layer to the measured temperatures.
Using measured ground temperatures also requires proper treatment of other
climate quantities:
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"Relative humidity":
The soil usually has a fairly "constant relative humidity";
if plant cover is present, the humidity is at least about 99%, since
otherwise the plants could not overcome the soil's hydraulic tension and
were not able to draw water from the ground. For simulation of components
in contact with the ground, WUFI therefore uses a constant relative humidity
as boundary condition whose value you can enter according to your wishes.
"Radiation":
Since there is "no radiation" within the ground, the
solar radiation data from the climate file are ignored.
"Rain":
Since there is "no rain" within the ground, the rain data
from the climate file are ignored. If you want to simulate the uptake of
(pressureless) ground water, it would be preferable to use an appropriately
tailored *.KLI file.
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"Relative humidity":
Depending on the selected temperature option (see above) it may be necessary to
adjust the relative humidity for a different temperature level or to set it
constant.
"Radiation":
Depending on the selected temperature option (see above) it may be necessary to
suppress solar radiation.
Otherwise you have the option to bypass the usual conversion of solar radiation
for the specific orientation and inclination of your facade, and to directly read
and use radiation data measured on the facade (if available).
"Rain":
Depending on the selected temperature option (see above) it may be necessary to
suppress rain.
Otherwise you have the option to bypass the usual conversion from normal rain to
driving rain and to directly read and use rain data measured on the facade (if
available).
For this purpose, set the rain coefficients
to R1=1 and R2=0.
Also, see the reference The *.WET Format
for Climate Data for details.
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*.KLI files:
*.KLI files contain data describing the
outdoor climate (rain, radiation, air temperature, relative humidity) and data
describing the indoor climate (air temperature, relative humidity). If you assign
a *.KLI file to the left side of a component, WUFI usually reads the outdoor climate data
from the file; if you assign a *.KLI file to the right side of a component, WUFI usually
reads the indoor climate data. This dialog allows you to override these choices. Rain and
radiation will then be ignored.
*.TRY, *.DAT, *.WAC, *.IWC, *.WBC files:
No options are available for these file types.
