THERM - Glazing Cavity Surface missing for Glazing system imported from Window

grasshopper honeybee-legacy
1

Hi All,

I am trying to automate the THERM calculation of a window system using Honeybee.
I encountered a problem with the Import Window Glazing system component in Honeybee legacy. Please see below a screenshot. The surface temperature of HB generated glazing system (right) is much lower than the one imported from Window directly (left). Everything else is the same as generated by HB in these two THERM files.

I found the discrepancy is caused by the missing Glazing cavity surface boundary condition (the red lines around the air space in the directly imported glazing system) in HB generated glazing system, though the information of these BCs are in the glazing report used by this component. These two boundary condition overrides the surface temperature and emissivity, etc during the calculation. The omission of the glazing cavity BC caused inaccuracy in the dew point line and u-factors.

Does anyone have suggestions on how to solve this issue? Can we add this BC using HB? or is there a way to directly import the glazing system without using the txt report from Window?

Window Glazing system imported from Window VS. generated by HB
Window Glazing system imported from Window VS. generated by HB1762×901 40.4 KB

2

Hi @Archiscript ,

I think the issue might be the result of a bug in the .thmx file parsers built into THERM as I remember having difficulty getting them to import glazing systems correctly. If you save the file with the correct glazing system boundary conditions as a .thmx file and then re-import the .thmx file to THERM, does the boundary condition survive the process? If so, then there’s hope that we can fix it on the Honeybee end and you should upload the .thmx file and I’ll get the honeybee components to emulate it. Otherwise, it’s a bug on the THERM end of things and there’s nothing that I can do to help here except point you to the THERM forum.

3

Hi Chris,

Thank you for the quick reply. I tried your suggestion and the glazing cavity surface did not survive the re-import from thmx to thm. I will ask on THERM forum and if I have an answer, I will post updates in this thread.

1 Like
4

Thanks @Archiscript ,
I am anxious to know if you get a helpful answer from the THERM forum. Keep us posted.