Exclude zone from floor area

wooseung · March 1, 2022, 2:26pm

Hi everyone. In the legacy version, it seems that a zone can be excluded from total floor area calculation through the ‘part of area’ in the ‘set zone properties’. However, such function cannot be found in LBT 1.4.0. How can I do that? I’d appreciate it if you could help me.

chris · March 3, 2022, 12:23am

You’ll have to be more specific, @wooseung . In which calculation are you trying to exclude a room’s floor area? There are lots of calculations throughout honeybee where the floor area is used.

wooseung · March 3, 2022, 8:31am

Thank you @chris for your answer. I would like to get a HVAC EUI of a building. But when assumed that there is a plenum space in the model, I would like to exclude the area of that plenum space from the EUI calculations.

chris · March 3, 2022, 4:28pm

Hi @wooseung ,

Thanks for clarifying and see now that you’re talking about this “part of total floor area” property on zones in EnergyPlus. I can see why this is useful and it’s something that should be integrated into the HB Plenum component along with also being exposed on one of the Honeybee 0::Create components like the HB Set Story component. So I think we should natively support this in Honeybee and I opened an issue for it here:

github.com/ladybug-tools/honeybee-core

Add an exclude_floor_area property to Honeybee Rooms

opened 04:08PM - 03 Mar 22 UTC

chriswmackey

enhancement

Someone recently explained to me why this is really important when people want t…o discount plenums in floor area calculations. I debated whether it should be a honeybee-core property or a honeybee-energy property but I think that it has a lot of uses beyond a particular simulation engine or honeybee extension. So we should add it as a core property to Honeybee-core Rooms and Honeybee-schema. Then, we should: 1. Make sure it gets translated to this "[part of total floor area](https://bigladdersoftware.com/epx/docs/9-6/input-output-reference/group-thermal-zone-description-geometry.html#field-part-of-total-floor-area)" property on zones in EnergyPlus. 2. We should also integrate into the [HB Plenum](https://docs.ladybug.tools/hb-energy-primer/components/0_basicproperties/plenum) component along with also being exposed on one of the Honeybee `0::Create` components like the [HB Set Story](https://docs.ladybug.tools/honeybee-primer/components/0_create/set_story) component. 3. Lastly, we should probably account for it in the recent "HB Geometry Properties" component, which gives floor areas for whole models (including net floor areas with construction thicknesses subtracted). More information is here: https://discourse.ladybug.tools/t/exclude-zone-from-floor-area/17605/2

It will take me a bit of time to implement but you can track the progress on that issue. In the meantime, here’s a custom GPython script that you can use to edit the OSM to exclude certain rooms from the floor area calculation.

manually_exclude_floor_area.gh (47.6 KB)

wooseung · March 4, 2022, 12:21am

Thank you very much for opening the issue, @chris. The files that you have provided are also really great help to me.

chris · March 10, 2022, 4:21pm

I just wanted to say here that excluding the floor area is now officially supported natively in honeybee. There are a couple of ways that you can exclude the floor area for a given Room. One is with the “HB Set Multiplier” component, which now has an excl_floor_ input.

Another is with the “HB Plenum” component, which will now exclude the floor area of the Plenum by default unless include_floor_ is set to True.

Excluding the floor area of a Room will affect both the EnergyPlus EUI output by the HB End Use Intensity component as well as the floor are of Models plugged into the “HB Geometry Properties” component.

Thanks again for bringing this up. Hopefully, this makes it easier to model buildings with a lot of plenum and attic spaces.