Hello, everyone.
Is there any way to take into account reflected radiation from neighbouring buildings that adds up to direct solar gain when calculating the cooling load of an indoor area?
Thank you
Marcello
In the HB Shadow Calculation component, to be used as an input to the HB Simulation parameter component, which in turn is an input to HB Model to OSM, you find these parameters to be set in solar_dist:
So by default (3) already implements reflections as a calculation. For simple geometries you can use (4). If surrounding buildings and/or terrain are modeled as shading (it usually is) then it has to be implemented for each shading surface you want to reflect the class:
ShadingProperty:Reflectance,
Name_Shading_Surface, !- Shading Surface Name
X.X, !- Diffuse Solar Reflectance of Unglazed Part of Shading Surface
X.X, !- Diffuse Visible Reflectance of Unglazed Part of Shading Surface
X.X, !- Fraction of Shading Surface That Is Glazed (if present)
Glz_Construction_Name; !- Glazing Construction Name (if filed above is >0)
By appropriately varying the data and entering in _add_str in the HB Model to OSM component.
Cheers
Massimiliano
Thank you Massimiliano.
I think I did exactly what you said, but if I change the reflectivity of the shader, the cooling energy intensity does not change.
Below the model. The windows are on the northern elevation and the shader is the purple building.
I attach the .gh file
Canyon.gh (171.2 KB)
Thank you!
Marcello
Hi Marcello,
opening the file gave me an error in the python script, simply the variable name “unglazedVisRef” was being called in the script by other name.
That was not the problem however, opening the.idf you notice two things:
- The name called in the shading:reflectance class is not the same name given to shading, obviously it must be the same.
- the construction name “exterior window” does not exist in the construction class, again it must be the same.
Corrected these two things it should work.
Pay attention to the therm_absp_ values of the asphalt which should be 0.90-0.94 that is equal to the emissivity. Instead solar and visible are often very similar.
In this case you have also given asphalt construction also to the first thermal zone of the building. I usually use a shading also for the ground part to which you then give the reflection as above. It doesn’t make much sense to use a thermal zone, but that’s just a suggestion.
I hope I have helped you.
Good work
See you soon
Massimiliano
We wrote at the same time. 
If you turn over to me the .idf file you generated with your solution I can tell you if everything is set correctly.
However, the glazing part of the shading reflectance is missing.
If you need it, let me know.
Good work
Massimiliano