Question regarding HB to OSM custom energy results (solar transmission between zones)

grasshopper honeybee-ph
,
1

Hello Everyone,

I have a question regarding Honeybee custom energy results in HB to OSM simulations.

I have a model with two zones:

1- Outer zone with exterior windows
2- Inner zone connected through adjacent/interior windows

Solar radiation should pass from the outer zone into the inner zone through these interior apertures. Radiance daylight results look correct, and I can clearly see light passing through both zones.

However, in the EnergyPlus results I observe the following:

Zone Windows Total Heat Gain Rate shows values only in the outer zone
Inner zone shows zero values for the same output

At the same time:

Custom Output “Enclosure Interior Windows Total Transmitted Diffuse Solar Radiation Rate” shows solar transfer from outer zone to inner zone
Diffuse radiation appears to pass through to the inner zone, Beam radiation is visible in the outer zone only

So I am confused about the energy reporting:

Why does the inner zone show zero in “Zone Windows Total Heat Gain Rate” even though solar is clearly transmitted through interior windows?
Is solar energy in the inner zone only represented through surface heat gain and convection instead of window-based gains?
Which output should be used to correctly represent solar radiation in the inner zone?

Could you please clarify whether this is expected EnergyPlus behavior or if I am missing a correct output for interior solar gains?

Thank you.

2

EnergyPlus uses a simplified method for transmitting solar through interior windows. Essentially, all transmission is diffuse and this is done for calculation speed reasons. More information is here in the E+ Engineering Reference:

3

@chris Thanks Chris for answering and sharing the right information. That really helped me understand the issue better. I will also check the Engineering Reference for more details.