I've just started using STAN, so I hope the answer to the Question is not too obvious, but:
Is there any way, that you can Display Energy flows and material flows on the same Level? Like not making a new sub-System or smth similar.
Many thanks for your help.
You cannot display energy and mass flows in the same graph.
If you haven't heard so far about the layer concept of STAN: you can add an energy layer to your model and display the mass flows or the energy flows for the same model by switching between these layers.