process with stock and transfer coefficients

Hi,
I am trying to build a model and I have a process that has a stock and I would like to add transfer coefficients. Why is this not possible? Is there a solution to this issue?

Thank you!
Lev

It is not possible to define transfer coefficients in a process with stock. A transfer coefficient is defined as the ratio of a certain output flow of a process to the sum of its input flows. If you have a stock it is not clear without data whether the change in stock (dstock) is positive (accumulation of material) or negative (depletion of material). In the first case dstock would have to be considered like an output flow and in the second case like an input flow.

If you are sure that there is e.g. only an increase in stock (= positive dstock) then you can model this behaviour with a subsystem (see atachment). Notice that if a subsystem contains stocks their sum will be automatically displayed as stock of the subsytem. Inside of the subsystem you have to add one process that is used to assign transfer coefficients to the output flows of the subsystem AND the flow that is going into a second process with storage function only (it has no output flow).

main system:


subsystem:


Hope that helps,
Oliver

Thanks alot!