Supplier, Feed-In, Source, Sink
For the material models, there are components for suppliers and feed-in on the one hand and for sources and sinks on the other.
Supplier and Feed-In Components
The symbols of the supplier and feed-in components differ from those of the other components in their graphic design: they have a transparent background and no frame.
The supplier components (see figure below) include:
The feed-in components (see following figure) include:
Supply/Feed-In
Only two of these components function bidirectionally in relation to the material model: they can supply and receive energy via the same pin. These two components are the Electricity_Supplier and the component External_Heat_Supply_And_Feed (the latter from the Heat Transfer folder). They can supply other components with energy as well as receive energy fed in by other components.
The other components only work in one direction. There are supplier components, such as Cooling Supplier, District Heating Supplier, Fuel Supplier, which supply energy or materials to other components, and components for feed-in, which receive energy or materials generated by other components, e.g., Fuel Grid Feed-In, District Cooling Grid Feed-In, District Heating Grid Feed-In.
Input Data
In the Technical input data of the supplier and feed-in components enter the Ecological input data CO2 emission factor and Primary energy factor (PEF) to carry out the life cycle assessment. Optionally, annual rates of change can be specified for the ecological factors. To do this, open the selection field by clicking on 
under the respective heading Annual modification rate for ecological impact factors. The drop-down list opens in which you can select Use annual modification rates for ecological impact factors. When this function is activated, the input mask above is expanded to include additional input fields for the Annual reduction of the CO2 emission factor and of the Primary energy factor (PEFs) as well as for the Minimum CO2-factor and the Minimum primary energy factor (PEF).
For Supply/delivery and feed-in, the ecological factors and their rates of change are entered separately (see following figure).
Only the Investment and Reinvestment costs can be specified as Economic input data for the supplier and feed-in components. The Investment costs include, for example, the connection costs, which must be taken into account in a structural optimization to determine the optimum connected load.
Sources and Sinks
Sources and sinks are almost without exception characterized by circular symbols (see the following figure).
Sources and sinks do not have an input form for CO2 emissions and primary energy; they are always located within the LCA space.
There are the following sources and sinks:
