When preparing a model for energy analysis, you can use masses to create custom thermal zones.
Use custom thermal zones to more accurately reflect your design intent when automatic thermal zoning does not meet the energy analysis needs of your model. For example, you may want to model a large atrium that spans multiple levels and so should be represented by its own thermal zone.
Custom thermal zones can be useful in the following cases:
- You have an idea how the building might be zoned.
- You are more interested in customizing the zoning layout than the overall form of the building.
- You are building an energy model to export to gbXML, and you want the zones to be customized.
To use custom zoning, create a model that uses conceptual masses (the model may or may not include building elements), and define the following parameters in the Energy Settings dialog:
- Mode: Use Conceptual Masses or Use Conceptual Masses and Building Elements
- Perimeter Zone Depth: 0 (zero)
- Perimeter Zone Division: disabled
Then create zones by modeling separate forms inside a mass, cutting one mass form from another. Wherever a form is intersected by a mass floor, the simulation interprets a separate mass zone.
| Using one mass for the main building with automatic zones gives this result. | Defining a mass form in the main building gives a different zoning result. |
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To create an atrium, create a smaller atrium mass form that has a different mass floor configuration from the larger mass model. Place the atrium mass inside the larger mass model.