Usage of flows

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WouterLCA
Posts: 3
Joined: 18 Sep 2012 08:02

Usage of flows

Post by WouterLCA » 18 Sep 2012 12:24

Hi guys,
I am doing a LCA on a small-scale wind turbine but I have encountered one or two problems and i was wandering if anyone can help.

I have modeled the system separately for its different materials,i.e Aluminum, Copper..etc and then want to use the collective results as the overall impact. It should be fairly straight forward, but some things just don't seem to work.

Questions
- When you use a process like 'Secondary Aluminum shape casted' does it include the flows that make up for example "Primary Aluminium Ingot"? (Because the aluminium I will be using for my turbine is already formed, is it correct to use the "Secondary aluminium shape casted" as the input for my processes?)

- I have built the system for aluminum which is currently working. The system is very similar to the 'Beer Can example' that was done in OpenLCA, except the primary aluminum ingot input has been changed to Secondary Aluminum shape casted. When i try to use this same logic for copper it doesnt seem to work correctly. The problem is that when using an input flow such as 'Copper wire' it seems like the "Copper wire" process has outputs but no inputs! This is different when using "Secondary Aluminum shape casted" instead of copper wire. For the Secondary Aluminum shape casted process inputs are present.

I would greatly appreciate some help and I am looking forward to a response.

Wouter van Rooyen, (Unviversity of Stellenbosch)

aciroth
Posts: 750
Joined: 09 May 2010 23:28

Re: Usage of flows

Post by aciroth » 18 Sep 2012 16:22

Hello Wouter,

this is of course more a data than a software question? The beer example uses the NREL database, from a previous edition. Here, the secondary aluminium (or aluminum) data set finally goes back to an aluminum recovery process, where aluminum is created "out of nothing" (you see that the process has only transport efforts and produces aluminium). This is a modeling decision. If you disagree to this for your model, you should add a secondary aluminium input to this process.
al_recovery.png
al_recovery.png (75.6 KiB) Viewed 7499 times
Also for copper, you should modify the original process (probably best in a copy of the process) if you disagree with the original modeling.

I hope this helps!
Andreas

WouterLCA
Posts: 3
Joined: 18 Sep 2012 08:02

Re: Usage of flows

Post by WouterLCA » 20 Sep 2012 21:57

Hi Andreas,
Thank you for the quick reply really appreciate it.

I am still busy trying to model the copper for my system, but have still not quite figured it out yet.
When i input the 'Copper wire, consumption mix, at plant.....' process into a product system it doesn't display any inputs for this process. As seen in the product system posted in attachments.

BUT, looking at the inputs and outputs of the process alone it is clear that there are both inputs and outputs for this process. (Also posted in attachments)

Regards

Wouter
Attachments
Product system.png
Product system.png (233.89 KiB) Viewed 7467 times
Process.png
Process.png (249.28 KiB) Viewed 7467 times

aciroth
Posts: 750
Joined: 09 May 2010 23:28

Re: Usage of flows

Post by aciroth » 21 Sep 2012 16:34

Hi Wouter,
the graph view in openLCA shows only the products, not the elementary flows (reason is that only the products can be used to connect processes). You have inputs for the copper wire process as LCI result (check the process view if you are in doubt - right-click on the copper wire box in the graph view and check 'open in editor'), but they are all elementary flows, and hence not visible in the graphical editor.
Cheers,
Andreas

WouterLCA
Posts: 3
Joined: 18 Sep 2012 08:02

Re: Usage of flows

Post by WouterLCA » 26 Sep 2012 08:02

Hi Andreas,
Ok i see now that the process indeed has inputs flows, but say now you calculate the life cycle inventory for a simple process that has for example; copper wire or cement as an input (as attached) - why are all the characterization amounts 0, even though you can see that the life cycle inventory has been calculated? For other metals this was not a problem.

Regards

Wouter

aciroth
Posts: 750
Joined: 09 May 2010 23:28

Re: Usage of flows

Post by aciroth » 28 Sep 2012 16:10

- you did not attach an image? Of course, the flows in the processes need to be recognised by the LCIA method you use.

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