[FEATURE] PiecewiseEffects for Flows

[JonaGL]

Prerequisite Checks

• I have searched the existing issues and confirmed this feature doesn't already exist.

• I have checked the documentation to ensure this feature isn't already available.

Is your feature request related to a problem?

At the moment I'm not able to model the piecewise (in reality non-linear) relationships between flows and effects.

Describe the solution you'd like

I would like to use PiecewiseEffects in Flow:
flixopt.Flow( ... , effects_per_flow_hour=flixopt.PiecewiseEffects( ... ))

Energy System Use Case

I try to implement pressure losses for transmission objects on a very simplified basis. The pressure loss of a pipe is non-linear in respect to the flow in the pipe. To represent the pressure loss more precisely, I would like to use PiecewiseEffects.

Desired Code Example (optional)

# example with pressure losses, which my_effect takes into account
my_piecewise_effect = fx.PiecewiseEffects(
        piecewise_origin=fx.Piecewise(flow_list),
        piecewise_shares={my_effect.label: fx.Piecewise(pressure_loss_list)},
    )

flixopt.Flow( ... , effects_per_flow_hour=my_piecewise_effect)

Component Category (if applicable)

Network/Grid (transmission, distribution)

Alternatives considered

No response

Additional context

No response

[FBumann]

@JonaGL Thanks for your request.
We will work on this.
It might also be possible to use a linear Transformer with fx.PiecewiseConversioninstead.
This would lead to the losses being accounted for in a Flow (with a connected Bus and Sink probably), instead of an Effect.
You should be able to achieve what you are looking for while we work on a more elegant solution.
If you have any Questions on this don't hesitate to ask here.

[FBumann]

@JonaGL I will try to solve this on Friday. I can't promise that I'll finish it, but ill keep you updated.

[JonaGL]

@FBumann Thanks a lot!

[FBumann]

@JonaGL i hope you got the news #310 (comment)