HB Glass Material (for E+) - Glazing properties issue: how can i assign both the frontside and backside solar reflectance of glazing

Hi all,

I am trying to model the total solar radiation transmitted from a window,

whose glazing has a solar control coating. When a glass has a coating (e.g. solar control or low-e), the solar reflectance of the glass frontside and backside should differ. My problem is that the HB Glass Material component has only one input called “reflectance” to set the frontside reflectance (the input calls it “frontside” if you hover over). I set this value, and then when I look at the material that is output from the component, I can see that the same value has been assigned to both front and back sides of the glass. Can someone please advise, perhaps @chris knows this, how can i set both the frontside and backside reflectance of the glass? Here is a screenshot that shows the issue:

Any advice would be highly appreciated.

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@behroozkhalilinasr1 ,

The solar_reflectance_back is exposed on the SDK layer of honeybee_energy. You can see it under the EnergyWindowMaterialGlazing class.

So you can set the back reflectance to be something different than the front using a line of Python inside a GHPython component like so:

mat.solar_reflectance_back = _ref_back

Here’s a sample:

custom_glass_material.gh (13.2 KB)

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Dear @chris,

Your script worked very well for us! the agreement very good when using banded data.

Thanks a lot for your support Chris! Highly appreciated.

Best regards,

Dear @chris

I have a question regarding a glazing property:
Is it possible to import the spectral properties of glazing?

Thanks for your help in advance!

Best regards,

Glazing spectral data is not available yet in LBT. But we’ll definitely get around to it and we’ll also add support for E+ frame objects at some point.

Hi @chris

Thank you for your help.
A similar question to the above, would it be possible to differentiate between visible and solar data (transmittance, reflectance)? and modifies more than 1 property simultaneously.
The component has only a generic input and the value inserted becomes valid for both, while in the case we would like to study they should be different.

Thank you in advance!

Not sure if I understand, @Matcos . The visible transmittance isn’t exposed on the component because it doesn’t really affect the E+ simulation for most cases. The only case where it can have an impact is for the daylight sensors assigned with the HB Apply Daylight Control component. But these aren’t nearly as accurate as a Radiance daylight simulation and they’re really just giving you a general sense of how much lighting energy might be saved if there were daylight controls.

Still, if this is the use case that you are worried about, then just tweak the source code inside the HB Glass Material component.

change_visible_trans.gh (8.2 KB)


Dear @Matcos
The script is attached to the first reply by Chris. you will find it above.