DesignBuilder is provided with an assembly library which contains a small database of typical components that may be useful in defining a CFD model. Some assemblies in the library include thermal gains while others simply provide an obstruction to airflow.
You can add your own assemblies to the library by selecting one or more component blocks and then using the Add assembly to library toolbar command (or Edit > Add assembly to library menu option).
The assembly library data can be exported for use in other projects using the File > Export > Export assembly library menu command.
The exported assembly library asl file can be loaded into other projects using the File > Import > Import assembly library menu command.