modelPressureDifferenceControl
Information
Purpose of model
Regulated pump due to a target pressure in the hydraulic grid. The model consists of a pump, two pressure sensors and a PID-Controller. The power of the pump is set by the PID-Controller so that the pressure difference at the bad point of the hydraulic grid remains constant at a target pressure difference. The pressure difference at the bad point is given by a RealInput. This control concept is often used in district heating networks. The Input for the PI-Controller is calculated using that input, the target pressure difference and a feedback block. The pump model is from the ClaRa Library and documented there. Furthermore, a similar pump model is used in the TransiEnt Library and explained in the documentation here:
TransiEnt.Components.Heat.PumpVLE_L1_simple
A limiter block is used to limit the output of the PID-Controller. The main difference between the model Pressure Control_p_input and PressureDifferenceControl is the controller. In this model a PID-Controller is used.
Interfaces
waterPortIn: fluid inlet for hydraulic grid
waterPortOut: fluid outlet for hydraulic grid
Delta_p_measured - RealInput for measured pressure difference
References
The pump model is from the ClaRa Library and documented there.
Version History
Model created by Tobias Ramm (tobias.ramm@tuhh.de) November 2015
Model modified by Lisa Andresen (andresen@tuhh.de) December 2015
Modeli documented by Jan Westphal (j.westphal@tuhh.de) August 2025
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Power | P_max | 2000 | Maximum electric power of pump |
| Modelica.Units.SI.Power | P_min | 0.1*P_max | Minimum electric power of pump |
| Modelica.Units.SI.PressureDifference | Delta_p_set | 1.2e5 | Set pressure at worst hydraulc point |
| TILMedia.VLEFluidTypes.BaseVLEFluid | Medium | simCenter.fluid1 | Medium in the component |
| Real | deviationThreshold | 0.1 | Deviation threshold before adjustment control (bar) |
| PI-Controller | |||
| Real | k | 5 | Gain for PI-Controller |
| Modelica.Units.SI.Time | Tc | 1 | Time constant for PI-Controller |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| TransiEnt.Basics.Interfaces.Thermal.FluidPortOut | waterPortOut | fluidport supply on consumer side | |
| TransiEnt.Basics.Interfaces.Thermal.FluidPortIn | waterPortIn | fluidport return on consumer side | |
| TransiEnt.Basics.Interfaces.General.PressureDifferenceIn | Delta_p_measured | at worst hydraulic point |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| TransiEnt.SimCenter | simCenter | ||
| ClaRa.Components.TurboMachines.Pumps.PumpVLE_L1_simple | pump_L1_simple | ||
| ClaRa.Components.Sensors.SensorVLE_L1_p | returnPressureSensor | ||
| ClaRa.Components.Sensors.SensorVLE_L1_p | supplyPressureSensor1 | ||
| Modelica.Blocks.Sources.Constant | p_set_Consumer | ||
| Modelica.Blocks.Math.Feedback | feedbackLoop | ||
| Modelica.Blocks.Math.Gain | gain | ||
| Modelica.Blocks.Nonlinear.DeadZone | deadZone | ||
| Modelica.Blocks.Math.Gain | pascal2Bar | ||
| Modelica.Blocks.Nonlinear.Limiter | limiter | ||
| TransiEnt.Basics.Blocks.LimPID | PID | ||
| Modelica.Blocks.Sources.Constant | zero |