In today's post I will show how we can define a mixed use occupancy in Revit to develop a more accurate energy model.
When Revit creates an Energy Analysis Model (EAM) the default occupancy for the entire building is defined in the Energy Settings dialog; i.e. the Building Type parameter. However, we often have buildings with drastically different spaces, like a storage space or a food prep area.
Here is a similar post I wrote earlier this year, that also gets into creating custom occupancy schedules: Insight Energy Model - Mixed-use facility and part-time space usage
Let's look at how we can test the Revit + Insight workflow to validate the results we would expect...
Project Overview
I created a simple one story model for this post. I saved four copies of the model, each with a unique name so they could all co-exist in the same Insight project. With all else being equal, I made the following edits and then ran an energy simulation (Insight uses DOE2.2).
Here are the four runs I performed:
- No Revit Rooms/Spaces, energy settings set to use Rooms
- No Revit Rooms/Spaces, energy settings set to use Spaces
- A single Revit Space added to largest room, Space Type set to Inactive Storage, energy settings set to use Spaces
- A single Revit Space added to largest room, Space Type set to Food Prep, energy settings set to use Spaces
Insight Results
Lets jump ahead to the end results in Autodesk Insight (see image below). The first two runs with no Rooms/Spaces added to the Revit model yield the same results regardless of energy settings being set to use Rooms or use Spaces. Since Revit finds enclosed spaces automatically, and Rooms or Spaces are not required, the analysis simply used the Building Type (i.e. Office) which is selected in the energy settings dialog.
The other two models had a single Space added, in the largest room. When a Space is present and energy settings is set to use Spaces, the Space Type data is used for that space (all other areas still default to Office). To highlight the effect I selected a low energy space (Inactive Storage) and a higher energy space (food prep).
As expected, the storage space uses the least amount of energy and the food prep uses the most. The office is in-between those two.
Building/Space Type Settings
Now, let's go back to Revit to see how this was set up...
First, here is a look at the Energy Settings dialog:
- Building Type: Office (same setting for all four runs)
- Export Category: Rooms (set to Spaces for subsequent three runs)
There is a lot of information packed behind the "Office" selection. Autodesk simplifies this for architects by providing all these common settings behind a single selection. This can all be customized, but that is not always necessary, especially for early energy modeling.
The following settings are found at Manage\MEP Settings\Building\Space Type Settings. Here are all the inputs for the Office selection...
When a Revit Space is added, from the Analyze tab, we have the option of changing the Space Type. When a space exists, and the energy settings dialog is set to use Spaces, a whole different set of inputs are used for this specific space as shown here...
Here is an enlarged view of the Space Settings for the two options I used in this example. Everything from the latent loads to the heating and cooling set points are different. If you open the three schedules, you will see they are different as well.
EAM Space Values
Finally, for this post, when the EAM is created, the summation of all the inputs (including location and true north) are wrapped up in the result. If you select the analytical spaces, you can see the info that will be used directly in the energy simulation...
Fun stuff!
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