modelSinglePipe_L2
Information
1. Purpose of model
Usage in simulation of district heating networks
2. Level of detail, physical effects considered, and physical insight
(no remarks)
3. Limits of validity
(no remarks)
4. Interfaces
(no remarks)
5. Nomenclature
(no remarks)
6. Governing Equations
(no remarks)
7. Remarks for Usage
For bigger simulations deactivate volume - underestimates the thermal delay by heating / cooling of the steel pipes.
Residence time is limited to 10h to improve initialisation at time = 0 with no mass flow present in the system.
8. Validation
(no remarks)
9. References
Heat transfer based on: B. van der Heijde, M. Fuchs, C. Ribas Tugores "Dynamic equation-based thermo-hydraulic pipe model for district heating and cooling systems", 2017
10. Version History
Model created by Philipp Huismann (huismann@gwi-essen.de) on 10.10.2018
Model revised by Philipp Huismann (huismann@gwi-essen.de) on 07.04.2022 | Pressure Loss linearisation for small mass flow rates, Residence Time limitation
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.SpecificEnthalpy | h_start | pipe_parameter.h_start | |
| SI.Height | z_in | 1 | Inlet Height of the pipe |
| SI.Height | z_out | 1 | Outlet Height of the pipe |
| Initialization | |||
| SI.Pressure | p_start | 10e5 | Pressure at start of Simulation |
| SI.Temperature | T_start | 90 + 273.1 | Temperature at start of Simulation |
| SI.MassFlowRate | m_flow_start | 1 | Mass flow at start of simulation - not used |
| SI.Velocity | v_nom | simCenter.v_nom | Design velocity of pipe. |
| HeatTransfer | |||
| Boolean | calc_initial_dstrb | true | Activates the calculation of a initial temperature distribution inside the pipes |
| Boolean | activate_volumes | simCenter.activate_volumes | Activate / Deactivate volumes to better represent delayed temperatrue changes due to heat capacity effects |
| SI.ThermalConductivity | lambda_insulation | 0.024 | Heattransfercoefficient of the insulation |
| SI.SpecificHeatCapacity | pipe_wall_capacity | pipe_parameter.pipe_wall_capacity | HeatCapacity of the pipe wall material |
| SI.Density | pipe_wall_d | pipe_parameter.pipe_wall_d | Density of the pipe wall material |
| Geometry | |||
| SI.Length | length | 10 | Length of the pipe |
| SI.Length | depth | 1 | Buried depth of the pipe |
| SI.Length | distance | 0.4 | Buried distance between pipe_pair - not used |
| SI.Length | diameter_i | 0.0217 | Inner Diameter of the pipe |
| SI.Length | diameter_o | 0.09 | Outer Diameter of the pipe |
| SI.Length | pipe_wall_thickness | 0.0026 | Pipe Wall Thickness |
| SI.Length | K | simCenter.K | average height of surface asperities |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| TransiEnt.Basics.Interfaces.Thermal.FluidPortIn | waterPortIn | Inlet port | |
| TransiEnt.Basics.Interfaces.Thermal.FluidPortOut | waterPortOut | Outlet port | |
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heat |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| TransiEnt.SimCenter | simCenter | ||
| Real | Q_loss | heat.Q_flow/length | Specif heat loss per meter |
| Real | dp_m | dp_residencetime.dp/length | Specif pressure loss per meter |
| Real | v | dp_residencetime.v_water | Velocity of the heat carrier |
| TransiEnt.Components.Heat.VolumesValvesFittings.Pipes.Base.pipe_parameters | pipe_parameter | ||
| Pipes.Base.dp_residencetime | dp_residencetime | ||
| HeatTransfer | hT_PlugFlow_LX_nom | ||
| HeatTransfer | hT_PlugFlow_LX_rev | ||
| Base.Fluid_Volume | fluid_Volume | ||
| Modelica.Thermal.HeatTransfer.Sources.FixedHeatFlow | fixedHeatFlow |
Contents
| Name | Description |
|---|---|
 HeatTransfer |