Using Revit Analysis Tools for Sustainable Design
Autodesk Revit models contain the data needed to perform early stage energy analysis, as well as later stage analysis for lighting. If you are unfamiliar with the analysis tools included with Revit or how to make sure the data being used is accurate, you may want to check out the on-demand Applied Software webinar, “Stay Accurate and Save Energy: Revit for Sustainable Design.”
During the webinar, Matt Dillon provided an overview of Revit analysis tools and workflows for sustainability in design, including a demonstration.
He pointed out that tackling sustainability in the early design phase of a project allows us to make changes that won’t require retrofits, complicate the project or delay the schedule. The workflows Matt covered in the webinar included:
- Conceptual design
- Schematic design and design development
- Autodesk Insight
The analysis tools in Revit are easy to use, quick, accurate, and give you actionable information early in the process. The analysis information can be put in the cloud for computations to proceed, so you can continue to work on other things locally.
The Energy Analysis tools can be downloaded and installed from the Autodesk Desktop Application. They use DOE-2 and EnergyPlus databases for very accurate results.
When preparing to do analyses in Revit, Matt advised to first set the building location and account for the orientation of true north (vs. plan north). Then set location, so it can correlate that to the DOE-2 database.
You can typically work with the defaults when doing solar analysis in Revit, which involves three steps:
- Analysis type
Photovoltaic with a few available standards
- Surface selection
All roof exterior surfaces
All mass surfaces
User selection of specific surfaces
- Results settings
If you have the Autodesk Architecture Engineering and Construction (AEC) Collection, you can use FormIt for quick conceptual modeling. When you generate mass models, you can get a very quick solar analysis.
Applied Software offers classes that provide indepth instruction on Revit tools and workflows.
Energy analysis is a bit more complex. It can be performed in FormIt, which is straightforward, or by using Revit which involves a few more steps.
With Revit, the energy settings need to be defined, and the energy model needs to be generated. The energy model can be tweaked at this point. Then the results can be pushed to Insight. Matt noted that you do not have to remodel to experiment with different scenarios. In Insight, you can upload your base model and look at different scenarios. He said, “You don’t have to make too many decisions early on.” You can vary components in Insight to see what effects they have on your energy requirements without changing your model. Once you find one you prefer, you can go back and adjust your model later.
With FormIt, you can perform energy analysis on conceptual masses with essentially a single mouse click. Using the “Generate Insight” tool, the computations are done in the cloud; when the Insight is ready, you can work on it in your browser on Insight.
When using the Energy Optimization panel on the ribbon, pay particular attention to whether you are using conceptual masses, building elements or a combination of the two. The default (Conceptual Masses and Building Elements) handles both and should be used most of the time. For conceptual masses, Matt’s advice is to leave the perimeter zone depth and perimeter zone division defaults on. They define the portion of the building that is bounded by an exterior wall, because these have different energy requirements than the core of the building.
Lighting analysis has a similar workflow, requiring location and orientation. For this tool, ensuring your material accuracy is critical, for instance glass transparency and reflectivity. Be sure to check the specifications of the materials your analysis will be based upon.
Matt explained that lighting analysis will require cloud credits, whereas solar and energy analyses do not.
When you run your analysis, you can choose to run a new analysis or view one that you generated previously. When you choose an analysis to run results for, that’s the point where you are charged cloud credits. You must accept, update and save the project to see your results.
Another option Matt suggested that is not as data-centric is using Cloud Rendering. This provides a more visual analysis. You can perform this just to check light levels in workspaces for example. It costs fewer cloud credits and still provides insight into light levels in a room.