Simultaneous equations error

[panos3]

Hello,

I've been trying to run my model but I am getting a lot o simultaneous equations errors one after the other. What is that exactly? and how can I solve it?

[Administrator]

You've got a bit of a logic problem in your model.

First of all, you've got "aluminium to be recycled (kg)", that's fine. This flows into "Aluminium Recycling Process" where it should remain until it is either recycled or not. The problem is you have "non-recyclable aluminium" and "recyclable aluminium" as dependant on "aluminium to be recycled (kg)", that cannot be correct. They should be dependant on the amount of aluminium in "Aluminium Recycling Process" delayed by a "process time". Once things are processed, they can then be split into "non-recyclable aluminium" and "recyclable aluminium".

So change the outflow of "Aluminium Recycling Process" to "rate aluminium processed". Now split "rate aluminium processed" into "non-recyclable aluminium" and "recyclable aluminium".

Aluminium Recycling Process = integ("aluminium to be recycled (kg)"-rate aluminium processed, 0 )
rate aluminium processed = Aluminium Recycling Process / time to process aluminium
"non-recyclable aluminium" = rate aluminium processed * coefficient of change 3
"recyclable aluminium" = rate aluminium processed - "non-recyclable aluminium"

Hope this helps.