The window is 90 ° (vertical position) and facing north. The heat transfer coefficient of the interior surface is set
to 0.13 m2K/W and the exterior surface is set to be wind dependent. Other selected properties for the exterior
surface; short wave radiation absorptivity = 0,925, long-wave radiation emissivity = 0,837, ground short-wave
reflectivity= 0,2.
5. Results
5.1. Temperature conditions on the exterior glazing
Figure 3 shows the temperatures in the multi-layer window over a period of 4 days for Bellenburg. The 4 days are
chosen to show the most unfavourable situation with cloudless sky at night. The figure illustrates how the surface
temperature on the exterior glass decreases to a lower temperature than the outdoor air temperature at night due to
the long-wave radiation to a cloudless cold sky.
Fig.