Use the Systems Analysis tool to create a load calculation or annual simulation report for heating, cooling, and airflow.
After analytical spaces are assigned, you can run a systems analysis. Revit uses a workflow to run the analysis. A workflow is a script that takes data from Revit, translates it to EnergyPlus, runs a simulation, and creates a report for design heating, cooling, and airflow. You can create your own customized workflow scripts. See the Autodesk University class, "Revit Systems Analysis Features and Framework-Creating Custom Workflows."
Two workflows are available by default: one for HVAC simulation and one for annual simulation. If the workflows do not appear in the dialog, you can set the folder location in the Options Dialog: File Locations Tab.
To run the systems analysis
The analysis runs in a background process so you can continue working. When the analysis is finished, you will be notified by the Background Processes on the Status Bar with a link to view the report.
Each workflow generates two report styles: a loads report and a detailed report.
Sizing loads are automatically added as properties to the analytical spaces at the end of the analysis.