i`m trying to model the production of a Aluminium die-cast part with openLCA 1.5.0 and the ProBas plus database.
In this database are many different unit and system processes for the production of aluminium.
I used a defined unit process for the production of the aluminium and made two unit processes for the production of the die-cast part and the transport of the part.
When creating the product system i set the options "add connected processes" and "connect with system processes if possible". The providers in the input of the processes are the predefined providers.
When i calculate the product system i get a negative GWP (-7kg CO2 eq.), which is very unrealistic for the production of a aluminium die-cast part.
Can anyone help me with what i`m doing wrong?
Is it better to work with the system processes of the database?