Difference between HB Annual Loads and HB Model to OSM

grasshopper honeybee
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1

Hi everyone,
I’m new to Grasshopper and Honeybee.

I’m currently running a façade energy simulation, and my goal is to determine the best geometry to reduce a building’s energy consumption. To do this, I’m analyzing the cooling and heating outputs from EnergyPlus.

I’ve run the simulation using both HB Annual Loads and HB Model to OSM, with exactly the same simulation parameters in both components, but I’m getting very different results. Can someone please enlighten me?

Here are my results summarized in a table:

Energy_facade_simulation_result_table
Energy_facade_simulation_result_table908×147 8.05 KB

This is a bit frustrating because, depending on which component I use, the optimized façade consumes either more or less energy than the reference façade.

Here is my Grasshopper file and a picture of it :

2

Somehow I cannot put my grasshopper file bc I’m new so here is a drive where my grasshopper file is :
https://drive.google.com/drive/folders/1j3-lZ8j9874mxbIEqDcGoPYP2NVTVwyQ?usp=drive_link

Here is also a picture of the parameters I have used for the simulation :

Energy_facade_simulation_parameters
Energy_facade_simulation_parameters827×535 50.8 KB

3

You should compare both IDF files with WinMerge and see what changes. Alternatively you can also use EPCompare.

Some time ago I had this similar issue. I think the HB Annual loads don’t take into account latent loads, you have to specify it. (I’m talking from memory, I might be wrong)

4

Before anything, I suggest you check a few things about yur odel:

  1. Scale: Seems to be you built it in cm instead of meters [as should be].
  2. There are no windows at all.
  3. The are open areas on the facade [open air]

I’m not sure these issues explain or correct the results, but seems to be fair to start with a “correct” built model.

-A.