# Write Modelica DES

![](https://3405893330-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-Ma9gBkJelXEQ5LsYEl7%2Fuploads%2Fgit-blob-083020824a04eb39e3fd501bc19e209cb3a89eff%2FWrite_Modelica_DES.png?alt=media)

![](https://3405893330-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-Ma9gBkJelXEQ5LsYEl7%2Fuploads%2Fgit-blob-4878c6ce7b9499591eadc71c60bc5fd418f86a9d%2FWrite_Modelica_DES.png?alt=media) - [\[source code\]](https://github.com/ladybug-tools/dragonfly-grasshopper/blob/master/dragonfly_grasshopper/src/DF%20Write%20Modelica%20DES.py)

Use an URBANopt geoJSON with a Distric Energy System (DES) loop assigned to it along with the corresponding scenario (containing building loads) to generate a Modelica model of the district system.

The model is generated using the modules of the Modelica Buildings Library (MBL). More information on the MBL can be found here: <https://simulationresearch.lbl.gov/modelica/>

The Modelica model produced by this component can be opened and edited in any of the standard Modelica interfaces (eg. Dymola) or it can be simulated with OpenModelica inside a Docker image using the "DF Run Modelica" component.

### Inputs

* **geojson \[Required]**

The path to an URBANopt-compatible geoJSON file. This geoJSON file can be obtained form the "DF Model to geoJSON" component. Note that the geoJSON must have a valid District Energy System (DES) Loop assigned to it in order to run correctly with this component.

* **scenario \[Required]**

The path to an URBANopt .csv file for the scenario. This CSV file can be obtained form the "DF Run URBANopt" component.

* **write \[Required]**

Set to "True" to run the component, install any missing dependencies, and write the Modelica files for the Distric Energy System.

### Outputs

* **report**

Reports, errors, warnings, etc.

* **sys\_param**

A JSON file containing all of the specifications of the District Energy System, including the detailed Building load profiles, equipment specifications, borehole field characteristics (if applicable), etc.

* **modelica**

A folder where all of the Modelica files of the District Energy System (DES) are written.