# Pressure Control

## Physical Model

The pressure control component enforces a specific pressure at the controlled_junction. This is achieved by adding a required pressure lift or pressure drop between the from_junction and to_junction, so that controlled_p_bar will be reached at the controlled junction. The controlled junction can be identical to the to_junction to control the pressure directly at the outlet.

Internally, the behaviour is achieved by fixing the pressure variable at controlled_junction in the system matrix and keeping the pressure drop of the pressure control unit variable, so that is calculated during the Newton-Raphson-calculation.

Note

The temperature at the inlet and outlet junction will not be adapted by the pressure control unit. Therefore, these components usually operate isothermal (inlet temperature = outlet temperature). It is assumed that temperature changes due to compression or expansion (Joule-Thomson-effect) are balanced internally by adding or removing heat.

Warning

A sufficient hydraulic connection between from_junction, to_junction and controlled_junction is crucial for proper operation of this component. Hydraulically impossible configurations (e.g., if the controlled junction is on a different stub) or contradicting other pressure control units will lead to non-convergence of the pipeflow.

## Create Function

For creating a single pressure control unit:

For creating multiple pressure control units at once:

## Component Table Data

net.press_control

 Parameter Datatype Value Range Explanation net pandapipesNet The pandapipes net object in whose press_control table the new unit will be added from_junction integer $$>$$ 0 Index of junction at which the pressure control unit starts to_junction integer $$>$$ 0 Index of junction at which the pressure control unit ends controlled_junction integer > 0 ID of the junction at which the pressure is controlled controlled_p_bar float > 0 Pressure set point [barg] control_active boolean If false, the unit behaves like an open valve loss_coefficient float > ß Pressure loss coefficient (only effective if control is not active) name string Name of the pressure control unit index integer > 0 Force specific index the press_control-DataFrame, if available in_service boolean True / False If false, the unit behaves like a closed valve. type string Type variable to classify different kinds of pressure control units (not considered by pandapipes’ calculations)

## Result Table Data

net.res_press_control

 Parameter Datatype Explanation p_from_bar float Pressure at “from”-junction [bar] p_to_bar float Pressure at “to”-junction [bar] t_from_k float Temperature at “from”-junction [K] t_to_k float Temperature at “to”-junction [K] mdot_to_kg_per_s float Mass flow out of pressure control unit [kg/s] mdot_from_kg_per_s float Mass flow into pressure control unit [kg/s] vdot_norm_m3_per_s float Norm volume flow [m^3/s] deltap_bar float Pressure difference between to- and from junction created by the pressure controller [bar]