How to specify the emmisivity of the exterior surface without choosing explicit radiation balance

[hs]

I am writing based on the wufi pro version 5.3.1 1273 DB 24.77.

In the former version of wufi pro 5.2, it was possible to specify the longwave radiation emissivity as well as shortwave radiation absorptivity explicitly without checking the explicit radiation balance option.
In the current version described above, the longwave radiation emissivity is grayed out to disable the explicit emissivity specification.
However it would be available to specify both absorptivity and emissivity if the explicit radiation balance option was choosed, it requires extra climate data.

Since it is vital to specify those two radiation parameters to accurately evaluate heat and moisture fluxes on the exterior surface in the context of urban heat island counter measure.

Please let me know how to specify those two radiation parameters without checking explicit radiation balance option.

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[Christian Bludau]

Without using the explicit radiation balance, the emission is not handled in the calculation, so we disabled that field. Earlier versions used a really simplified model, what only was usable with some climate files. For the most other climate files there was no calculation of the emissivity without using the explicit radiation balance. To show that clearly in the GUI, we disabled the field without radiation balance.

More information about the handling of radiation and the simplified overcooling model you can find in the programs online help in Topic 48 - Long-wave radiation exchange. Search for "long wave radiation".

Christian