[FEATURE] Add option to calculate the nominal temperature rise/fall

[moritzn-met]

What is your precise need ?

To set the nominal_cold_side_temperature_rise and nominal_hot_side_temperature_drop for the flue gas HEX can be a challenge. Sometimes we dont have HMBD information about this. So it would be good to add an option to direct calculate it e.g. like this:
HEX.nominal_cold_side_temperature_rise = HEX.T_hot_in - HEX.T_cold_in;
HEX.nominal_hot_side_temperature_drop = HEX.T_hot_in - HEX.T_cold_in;

What solution do you see ?

Add a parameter to the HEX components to decide if we want to set the nominal deltaT or calculate it.

[pierre-eliep-met]

Agreed, I think it should even be the default behaviour, and not with a parameter, and we should remove the nominal if I'm correct, the interest is the current deltaT not the nominal one

[pierre-eliep-met]

@nabily-met do you agree on this last point ?