Linking of processes in openLCA with ecoinvent 3.6

Question

Hello everbody, 

i have some questions about the connection of database processes:
 
1.    Are there any ecological expenses associated with elemtary product flows? Apparently not, if you can create your own product flows as well to connect  the different processes. 

2.    Difference Unit/ System process:
If I create two types of product system from a process XY (for unit and system processes) and compare these two in the modelgraph, the unit productsystem shows all the pre-chains of e.g. fuels and machines (market, production..), but not in the system productsystem. Are these pre-chains included in the content of the system productsystem, but are they only not shown?  

3.    If I change the amount of the output-flow (quantitative  reference) in prefabricated processes of the database,  e.g. in the process  "excavation, hydraulic digger" (from 1m3 to 500m3), how is it then ensured that the  inputs  (e.g. the diesel consumption for the machine operation) also increase? Do I have to adjust this manually via parameters or do the  program  itself.

Thanks in advance for any response.

Best wishes,

Max

Answer 1

Hi max, trying to answer your three points:

1) what do you mean with "elementary product flow"? In LCA one can dinstinguish product, waste and elementary flows. I have never heard of a elementary product flow.

After creation of a new product flow object in openLCA, no environmental impacts will be linked to this flow. This is done via modelling the life cycle and thus linking your new product flow already existing flows.

2) system processes aggregate the pre-chain, making them a bit intransparent. The impact result should be the same.

3) Please only do changes to database processes after you have copied them. This way, you ensure, that your changes only apply to your modelling efforts and are not used in the background for the whole database.

If you manually change 1 -> 500 m³ and the process is not parametrized, you also have to manually change all the other flow amounts.

But why would you even want a linear multiplication with 500?

If you need 500 m³ you could specify so in the process, which uses "excavation, hydraulic digger" as an input? This way all the flow informaton of "excavation, hydraulic digger" will be multiplied by 500