I get a negative impact result when calculation on just one flow even though this flow has positive impacts

Question

When I do a test calculation for just one Process in the PEF database I receive negative values. This occurs for various PEF Processes (materials) like "Alkyd resin dispersion (self-emulsified); technology mix; production mix, at plant; 50% in water"

When I inspect the impact values on the Process level they are positive as expected, so I am very surprised that they become inverted (negative) when I do a calculation.

Your help would be much appreciated.

Comments

How do you do the test calculation? You should not use the autoconnect option in the product system creation as GaBi processes are not meant for this, and it will result in funny supply chains.

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I add the Flow as Input. In this case  "Urea formaldehyde resin".  I do "Direct calculation" of the Process.  It then shows the impact as negative values?
I find the "Urea formaldehyde resin" in the PEF database under Materials production/Organic chemicals/nan/Urea-formaldehyde resin.

Answer 1

Thank you for the further explanation - direct calculation makes a product system with autoconnect and calculates this directly, on the fly, therefore you should not use direct calculation for PEF and GaBi-like databases.