For mixed-use facilities and areas with reduced occupancy, we need to use the Space command, in Autodesk Revit, to properly define this for the Insight energy model. That is the topic of today's post.
Definitions for this post:Area: A physical volume within a buildingRoom: A specific Revit command/element (Architecture tab)Space: A specific Revit command/element (Analyze tab)
First off, if you are familiar with the Revit + Insight workflow, you may already know that Rooms or Spaces are not at all required. This is because Revit uses a special voxel algorithm to find enclosed areas. For today's post we'll see an example of this, and how various combinations can be used; for example:
- no rooms/no spaces
- no rooms/some spaces
- some rooms/no spaces.
No Rooms
The first example, see image below, has no Rooms placed. Revit still finds these three enclosed areas within the building, which can be seen in the Energy Analysis Model (EAM) within Revit.
Some Rooms
If, any rooms exist the only thing used from those elements is the room name and room number. This info appears in the EAM schedules in Revit, and can be helpful in keeping things organized and for some troubleshooting. But, they offer no additional value in the energy modeling process.
Some Spaces
Like Rooms, Spaces are not required... but, when used they offer a whole new world of EAM options for the area they occupy. The image below shows a copy of the same model shown above. This copy has two areas with no rooms or spaces, and one with a space placed.
When the Space is selected, we see an Energy Analyses section within the Properties palette (see image below). We will focus on Space Type for today's post. The default for all Spaces is <Building>. FYI: areas with no spaces use the Building Type set in the Energy Settings dialog, which is Office by default.
Clicking on <Building> and then the "..." icon, you will see the Space Type Settings dialog shown below (click to enlarge). Here you can see a collection of important inputs in any building energy model. One of those key inputs is the occupancy schedule. Clicking the selected value opens the Schedule Settings dialog.
For comparison, selecting another Space Type, we can see the occupancy schedule is very different. Hotels are used more in the evening than during the day.
Mixed-use example: for a mixed use highrise building where a number of floors are hotel, simply place spaces on those floors and change their Space Type to hotel and you're done!
In the case that a room(s) is only used part-time, you can create a custom occupancy schedule for a specific Space Type (see image below).
Part-time area use example: In the example above, with the single space, I selected a different Space Type option and applied a new/custom schedule, using the same schedule for occupancy, lighting, and power.
Energy Settings dialog
If Spaces are used, it is very important that the Export Category is set to Spaces in the Energy Settings dialog. This tells Revit to look for Spaces when creating the EAM.
Results
The Insight results of the two buildings can be seen in the image below.
- Rooms Example: 94.2 pEUI Mean (all three areas using Space Type 'office')
- Spaces Example: 84.6 pEUI Mean (two areas using 'office' and one using 'warehouse' with a 20% occupancy schedule)
Clearly, when one-third of the building is only used 20% of the time, the overall building EUI would be lower than all areas being used full-time. We can see that in the rough 10% pEUI difference (FYI: there are other input changes between the two space types, like set points, that also contribute to this difference). A word of warning: be careful not to over use this option, as areas are often repurposed post occupancy.
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