2D:Dialog ClimateFileDetails

Dialog: Climate File | Details

Some climate formats offer additional options:

*.WET files:

*.WET files can contain additional measured data that might be useful for a hygrothermic simulation:

"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.
 

"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 coefficient for the surface to a large number. WUFI then reads the corresponding temperature from the file and uses it as the 'air temperature' for the calculation; the large heat transfer coefficient takes care that the surface assumes the same temperature.
Using measured surface temperatures also requires proper treatment of other climate quantities:
 
"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.
 

"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 coefficient for the surface to a large number. WUFI then reads the corresponding temperature from the file and uses it as the ambient air temperature for the calculation; the large heat transfer coefficient 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:
 
"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.
 

"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 coefficient for the surface to a large number. WUFI then reads the corresponding temperature from the file and uses it as the ambient air temperature for the calculation; the large heat transfer coefficient 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:  
"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.
 

"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 *.WET Format for Climate Data for details.

 

*.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). This dialog allows you to specify which one of the two shall be applied to the surface segment under consideration.

 

*.TRY, *.DAT, *.WAC, *.IWC, *.WBC files:

No options are available for these file types.