Dragon fly urban scale shading and demand clarification

from_building_solids_simplified.gh (74.4 KB)
I faced few question working with dragon fly’s sample files.
I simplified one of the model you can find in attachment, lets consider that the goal of this sample simulation is : calculating cooling and heating demand considering shading factor. (Shading of buildings on each other)
I defined two Breps (representing two buildings)
{I want to use honeybee for simulations as I had problems installing UrbanOpt}

And I have few questions:

1- for shading effect of buildings on each other, shading is something that should be define by user or it will be defined automatically ?
I mean in Model Component ( DF Model) should I import all buildings as context or it’s not needed.

2- to consider the cooling and heating “demand” I want to make sure that adjusted COP and HVAC IDeal are defined. which component do you suggest to add in for this algorithm?

3- as I understood at the end the results are for each building ,are the result based on the turns define with brep component? meaning first brep is the first in result.

Hi @az.sanei ,

1 - The default behavior of the dragonfly plugin is to export each Dragonfly building to a Honeybee model. In this process, any building that is not a part of the Dragonfly building is exported to the corresponding honeybee Model as context shade. You can use the shade_dist_ option to specify a certain distance from the building beyond which you are not interested in translating neighboring buildings to context shade. I recommend using the DF Model to Honeybee component to export your Dragonfly model to Honeybee models and then preview each of the resulting Honeybee models using the HB Visualize by Type component. Then, you can see exactly what is being simulated in each honeybee model.

2 - There’s no such thing as a COP for an ideal air system in EnergyPlus. So you can just run your simulation with the default ideal air systems and multiply the results with whatever you want afterwards.

3 - I don’t understand what you’re asking here but the resulting sql files from the “Model To OSM” component align with the order of the input honeybee _models. Does that answer your question?

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Thank you @chris I got point 1 and 2

about question 3, what I’m try to do is to simulate in block scale and at the end analyze the result for each building in the neighborhood.
to check that what I think should be done is to look in the results of “RoomEnergyResult” ( for example cooling) and each branch should represent one building. Based on your answer now I know the results are in order of the input honeybee_model.
the problem is:
I simplified a model with 2 building, but the result are showing 4 branches of monthly results.
is there any way to get monthly results for each building? I can’t figure it out why the results showing 4 branches. logically it should be 2 branches.


test.3dm (36.7 KB)
from_building_solids_simplified.gh (76.3 KB)

The results branches show each floor for each building. Some of them, in your case, are using the multiplier option.
You can try something like this to get the totals, normalized total and monthly results:


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That’s because each of your two buildings have two stories. So 2 x 2 = 4. When you use ideal air systems, you will get one set of cooling results per room (or story in this case).

Actuary buildings are not two stories each. one is a two story and other one is a four story building.
I considered the height of the 2 block test file different on purpose.

for question 3, I got the answer here:
It’s because use_multiplier_ is on! so the results for a four story building can be shown as 2 branches.

DragonFly missing stories in the middle - grasshopper / dragonfly-legacy - Ladybug Tools | Forum

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