modelConsumer_SLP
Information
Purpose of model
A model of a heat consumer for district heating networks. It consists of a pump, a heat exchanger and a P-controller. The P-Controller sets the mass flow rate through the pump so that the return temperature of the district heating network is kept constant. The heat is transported from the heat carrier through the heat exchanger. With a combi time table the consumed heat flow is set. A gain model is used to normalize the heat flow rate according to a given Q_flow_nom, which can be set by the user. SLP in the name stands for the standard load profile that is used for heat the heat flow rate.
This consumer model is used for the simulation of district heating networks. It calculates the mass flow rate flowing through the consumer, which is important for the numerics of a district heating network simulation. Therefore, a pressure difference has to be given by the hydraulic grid. The mass flow rate is limited by a parameter (m_flow_nom) inside the P-Controller. The calculation of the mass flow rate is independent of the pressure difference at the inlet and outlet. Therefore, the user has to pick sensible pressure values inside the hydraulic grid. An example of a pressure control is given in: TransiEnt.Examples.Heat.Largescale_DHN
Level of detail, physical effects considered, and physical insight
- P-controler
- Heat losses from the building to the environemnt
- Heat transport through the heat exchanger
Interfaces
fluidPortIn_simple: inlet for the heat carrier
fluidPortOut_simple: outlet for the heat carrier
Q_flow_demand: input for the demanded heat flow (it can be turned off with the boolean parameter useInput, then the heat demand is set by the combi time table inside the model )
References
The model is based on the model Consumer.Consumer
Version History
Model was created by Jan Westphal (j.westphal@tuhh.de) in August 2025
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.MassFlowRate | m_flow_nom | 0.18 | Nominal mass flow rate of the water (used to limit the output of the P-Controller) |
| SI.HeatFlowRate | Q_flow_nom | 8e3 | Nominal heat flow rate (used in the heat exchanger) |
| SI.HeatFlowRate | Q_flow_Ref | 6.0563e3 | |
| Real | gain_k | Q_flow_nom/Q_flow_Ref | |
| SI.Density | rho | 981 | |
| Real | k | 20 | Constant for proportional part of PI-controller |
| Real | y_max | m_flow_nom | Max. opening of valve |
| Real | y_min | 0.0001 | Min. opening of valve |
| SI.SpecificHeatCapacity | cp | 4186 | |
| Boolean | useInput | false | |
| String | relativepath | "/heat/HeatLoad.txt" | |
| String | path | TransiEnt.Basics.Functions.fullPathName(Modelica.Utilities.System.getEnvironmentVariable("publicData") + relativepath) |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| TransiEnt.Basics.Interfaces.Thermal.FluidPortIn_simple | inlet | ||
| TransiEnt.Basics.Interfaces.Thermal.FluidPortOut_simple | outlet | ||
| Modelica.Blocks.Interfaces.RealInput | Q_flow_demand |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| SI.HeatFlowRate | Q_flow_C | Consumed heat flow rate, just for evaluation | |
| TransiEnt.Components.Heat.SimplePump_mflow | pump | ||
| TransiEnt.Components.Heat.HeatExchanger_simple | heatExchanger | ||
| Modelica.Blocks.Sources.RealExpression | SetTemperature2 | ||
| Modelica.Blocks.Sources.CombiTimeTable | combiTimeTable | ||
| Modelica.Blocks.Math.Gain | gain | ||
| Modelica.Blocks.Continuous.LimPID | PID1 | ||
| Modelica.Blocks.Sources.RealExpression | SetTemperature1 |