Green Building Studio Building Assumptions and Details.
Green Building Studio is the Autodesk energy analysis computational tool which runs the Energy Analysis features in Autodesk Revit and Vasari. Green Building Studio has a rich and extensive database of intelligent defaults for building constructions, schedules, internal loads, HVAC equipment, and other inputs needed for the energy analysis.
The Revit and Vasari inputs that are exposed in the Energy Settings are primarily based upon CBECS characteristics and standard practices in the construction industry. You can edit these settings within the Energy Settings dialog in Revit and Vasari. Detailed descriptions of the settings can be found in the references described below.
Conceptual Constructions : Descriptions of the thermal characteristics of the walls, floors, roofs, windows, and skylight.
Building Operation Schedule Defaults : Descriptions of the default operating schedule applied to your model, based upon the project's building type.
Building Operating Schedule options : Descriptions of the operating schedule options that may be applied to your model.
Building Type Defaults (Include Link to Building Type): When performing energy simulation using Green Building Studio, you need to define the building type for your model. In order to generate an energy model for simulation, Green Building Studio uses a default value based on building type and project location if a parameter has not been defined in your model.
Outdoor Air Infiltration : The Outdoor Air value defaults to 15 cfm/person. By clicking on Edit you can edit this value using Outdoor Air per Person; Outdoor Air per Area; or Air Changes per Hour.
Additional input defaults used in the energy analysis, but not exposed in the Revit or Vasari Energy Settings, are based upon ASHRAE Standards. You can view these input assumptions by logging in directly to the Green Building Studio website. Navigate to your projects, choose the project, click on the specific simulation run you wish to review, and navigate to the Building Assumptions and Details section of the Energy and Carbon Results.
These defaults can be edited using the Green Building Studio Project Template, Project Default, and Design Alternative features.
For the more experienced users, you can download even more detailed inputs from the Green Building Studio website by going to the Export and Download Data Files tab associated with each energy analysis run. There you can download files such as the gbXML file (which is populated with the default analysis inputs), the DOE-2 input file, the EnergyPlus file, and/or the Weather Data file.
Green Building Studio also supports a workflow which allows you to upload gbXML files directly to the Green Building website. In cases where the energy setting parameters are not already defined in the gbXML files, defaults are applied which, in some cases, differ from the defaults used within Revit and Vasari. These defaults are primarily based upon the ASHRAE 90.1, ASHRAE 90.2, ASHRAE 62.1 and CBECS data, and vary with building type, location, size, and number of floors.
For energy settings where ASHRAE baselines do not exist, regional code baselines, or building survey findings are applied as a reasonable starting point for new construction projects:
Schedules: California Non-residential New Construction Baseline Study 1999
Envelope thermal characteristics, LPD, HVAC efficiency: ASHRAE 90.1 2007 and ASHRAE 90.2 2007
Equipment power density & DHW loads: California 2005 Title 24 Energy Code
Occupancy density, ventilation: ASHRAE 62.1-2007
HVAC system type default for building type/size & other miscellaneous building characteristics: 2003 Commercial Buildings Energy Consumption Survey