Q_nominal?

[gitfeldhase]

Hello everyone,

i am facing another question.
I was looking for the constraints for the optimisation and therefore checking out the HeatPipeline class.
I saw the variable "nominal capacity of heating pipeline".
However, this parameter is not defined in the invest data for the pipes (invest_data/network/pipes.csv).

Therefore I assume that in case the nominal heat flow Q_nominal is not defined, it will use Q_out of the adjacent pipe to calculate the losses.

.. math:: \dot{Q}_{loss}(t) = f_{loss}(t) \cdot l \cdot \dot{Q}_{nominal}

Is that correct?

This is where I think the nominal value (Q_nominal) is set:
class HeatPipeline(Transformer):
[...]

def _set_nominal_value(self):
    i = list(self.inputs.keys())[0]
    o = list(self.outputs.keys())[0]
    if self.outputs[o].nominal_value is not None:
        self.inputs[i].nominal_value = \
            self.outputs[o].nominal_value
    elif self.inputs[i].nominal_value is not None:
        self.outputs[o].nominal_value = \
            self.inputs[i].nominal_value

Best regards and thanks for the support.

[joroeder]

I am currently out of office. In short, there are two constraint blocks, if you are doing investment optimization, the nomial_value is none, because it is an decision variable. Think of extending an existing network, therefore you can also define heatpipelines with given nominal_value.

[clarapineau]

Hello, I am facing the same question regarding the extension of an existing network. Is it correct that for existing pipes I have to specify their capacity and there is no way to just specify a pipe type + length and let DHNx calculate the capacity?
Thanks for your work and kind regards.