Category Archives: BREIN

Tolerated intervals for integral quantities

Design targets for color values or other integrated spectral values may not always be well-defined numbers. You can also search for designs where color values stay within tolerated boundaries, but it does not matter where exactly.

Such design situations can be handled in CODE using so-called ‘penalty shape functions’. However, the use of this concept turned out to be rather complicated.

We have now (starting with version 5.02) introduced a very easy definition of tolerated intervals for integral quantities: Instead of typing in the target value you can define an interval by entering 2 numbers with 3 dots in between, like ’23 … 56′ or ‘-10 … -8’. If the integral value lies within the interval its contribution to the total fit deviation is zero. Outside the interval the squared difference between actual value and closest interval boundary is taken, multiplied by the weight of the quantity.

WOSP-UVIS

Based on the WOSP-LEDO light source we have developed a spectrometer system that can be used to measure reflectance spectra in the wavelength range 270 … 900 nm. The light source is based on LEDs only.

2 array spectrometers (not shown in the images) are used to record the sample signal and a reference signal at the same time. This makes the results independent of light source drifts.

Samples must be positioned within a few mm distance to the sample port of the system. The measured spectra are tolerant against small sample tilts or height differences.

Spectral quality is the same as for WOSP-LEDO. The unit can be used as a light source for transmittance measurements as well.

The system requires an external power supply of 12 V DC.

Leng model for optical constants

We have implemented (starting with object generation 4.99) the Leng oscillator which has been developed to model optical constants of semiconductors. As shown in the original article (Thin Solid Films 313-314 (1988) 132-136) it works well for crystalline silicon:


Warning: While the model works fine in the vicinity of strong spectral features (critical points in the joint density of states) it may generate non-physical n and k values in regions of small absorption.

Bugfix in BREIN

Depending on the configuration, it could happen that the main application brein.exe generated a *.csv file for each processed pane in the BREIN program folder. These files were meant to be generated for BREIN viewer, in the designated transfer folder, but happened to be generated even if BREIN viewer is not used at all.

We have removed this error in the latest version of brein.exe.

New fit option

We have included a new fit option which helps to increase the speed of analysis in time critical applications: In methods which use pre-fit sets in the list of fit parameters you can now include the current fit parameter values in the pre-fit search. This eventually avoids many fit iterations if differences between consecutive measurements are small.

The new feature can be turned on or off in the dialog of fit options.

 

Climate settings, window tilt angle, pane absorption and temperature computations

We have upgraded several CODE functions related to the technical performance of glazing products.

You can now compute solar pane absorption and pane temperatures for up to 6 glass panes.

The list of integral quantities in CODE features new menu items (in File/options):

  • set global climate parameters used for U-value, g-value and temperature computations
  • set the window tilt angle for all U-value, g-value and temperature computations

You can display climate values using labels in a view with the following names:

  • ‘selected_climate’ (shows the name of the climate)
  • ‘selected_climate_parameters’ (shows values of outside temperature, external heat exchange coefficient he, inside temperature, internal heat exchange coefficient, solar power
  • ‘selected_climate_ISO52022’ (shows the name of the climate settings for ISO 52022-3 computations)
  • ‘selected_climate_parameters_ISO52022’ (shows values of outside temperature, external heat exchange coefficient he, inside temperature, internal heat exchange coefficient, solar power, used for ISO 52022-3 computations)

You can display the value of the window tilt angle using a label called ‘window tilt angle’.

Finally, you can call the following new script commands to open user dialogs in the main view:

  • edit climate
  • edit window tilt angle