LBT Showing Results AFTER simulation - Workflow

I get the following issue and wanted to share the solution i’ve found to solve it.
I have a case already simulated. I want to show the results (for instance Energy Balance) without running the simulation again (the results are stored in my machine).
For those results that require to connect results data and model geometry (e.g. LoadBalance, ColorRooms, ColorFaces, etc) i get the following error:

  1. Solution exception:None of the data collections could be matched to the input rooms.

The results and the model inputs are just the same as the simulated but still there is this error.
The way to solve this (thanks @chris) is using the JSON file created during the simulation for the model and then use the LoadObjects to load the HB objects from the JSON file. This will provide the exact model that was simulated, matching, in this way, the results structure. If i quote @chris:

You can see here an image with the original model and the JSON model connected to the ColorFaces componen. The first one gives an error, the second one workst:

Attached the file showing the workflow i suggest to solve the issue (See especially the green-orange groups).

Hope this will be helpful for some of you.
-A. (111.6 KB)


Humm… I have a similar problem, but using the JSON Model does not appear to solve it. Workflow attached if anyone can advise / comment. And thanks.

2021 04 01 v1.2 Simple Model Mass and (142.5 KB)

After giving this some review, it appears that the load balance component works fine so long as the model uses the default Ideal Air System. The error occurs when i switch to a PSZ-AC system. So now i am curious if/how to use the Load Balance component when modeling various HVAC systems that are not the default Ideal Air System…

Well, I ran into the same trouble like @Octagon26.

In my model after exchanging the “HB IdealAir” with a “HB HeatCool HVAC” component, trying a “residential heat pump”
I also have the impression it’s related to the change of HVAC in the model. So I’m not sure if it good to deal with it in this tread, or if it’s a topic of it’s own?

Also with Octagon’s file updated it’s still the same with his configuration.

2021 04 01 v1.2 Simple Model Mass and (138.0 KB)

Has anybody an idea where to look or what to do about it?

You should check this discussion.
Energy Balance is good for Ideal Air systems and not intended for more detailed HVAC systems.

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@AbrahamYezioro I wish I would have read this sooner. If I am running a dragonfly model with an HVAC system, then there are no results to read? None to visualize? What results can I extract from running a specific system? So far, as above, none of the components I can find will visualize any results for a specific HVAC system. This is unfortunate, as my most recent run took 5 hours.

The results are those that you asked for before the simulation If you didn’t, there are default ones.
Can’t tell about HVAC systems.
What i suggest, before you do so long simulations is to try simple examples where you can control inputs/outputs.
Did you try the DF example files? From those i recommend checking the from_building_footprints file, where there is an assignment of HVAC systems to the building.


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I never got back to the from building footprint example. I have used the from building solids file many times now. I switched back to using the multiplier to keep the simulation times lower. @AbrahamYezioro Does using the multiplier mess up the conductivity, or is this being averaged over all floors? How do you handle those results in practice? Do you, for example, take the values and multiply them by however many floor plates are of the same size? I assume there is a GH widget for the math, but I have not been able to look since my machine is constantly running my terrible simulations. :slightly_smiling_face:

I’m still suggesting to create a simple case, 1-2 low buildings before jumping into the big pool.
The from building footprint example shows the use of HVAC systems. Just take a look to see how it is implemented there. You don’t need to go back to this example.
Using the multiplier option takes care of all calculations. You don’t need to do that by yourself (that would be crazy). The thing with the multipliers is that it is a good shortcut when you have repetitive floors with the same thermal conditions. In theory for a 10 floors building, you need to model 3 floors: Ground, Roof and 2nd floor. Then multiply the last (2nd floor) 8 times. It is a cool E+ feature. The assumption is that floors/ceilings of this floor are adiabatic , so there is no messing with the thermal properties.



Thanks for the explanation. I know this is probably stated a thousand different ways elsewhere. It is hard to keep track of it all with so many threads discussing degrees of differences in the LBT use. It must seem very stupid of me to consistently ask the same questions, but I do not really have much time to read between the lines and hunt for nuggets. Whenever I get a chance I will go back and look at the footprints example. For now, I will stick to manually extracting the values I need from the Eplus reports, per building. The visualizations are not intuitive.