modelHeatExchanger_simple
Information
Purpose of model
A model of a heat exchanger. It consists of two fluid ports and a heat port. The model is based on the three balance equations of mass, energy and momentum. A dynamic energy balance is assumed. The mass and momentum balance are assumed to be static. No pressure losses are considered.It is used for the modeling of radiators and the modeling of substations in district heating networks.
Level of detail, physical effects considered, and physical insight
L2 (defined in the CodingConventions)
- no pressure losses considered
- static mass balance
- constant fluid properties
- dynamic energy balance
- heat transport according to EN442
Interfaces
inlet: A fluid inlet for the inflowing heat carrier medium
outlet: A fluid outlet for the outflowing heat carrier medium
heatPort: A heat port for transporting the heat from the heat carrier
Governing Equations
Mass balance: m_in+m_out=0
Energy balance: V*rho*dh/dt=m_in*h_in+m_out*h_in-Q_flow
References
The model is an adapted version of: Components.HeatExchanger
Version History
Model was inserted by Jan Westphal (j.westphal@tuhh.de) January 2025
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.MassFlowRate | m_flow_nom | 1 | Nominal mass flow rate of the water |
| SI.Volume | V | 0.01 | Volume of the heat exchanger |
| SI.Density | rho | 1000 | Density of the water |
| SI.TemperatureDifference | delta_T_nom | 35 | Nominal temperature difference between supply and return temperature |
| SI.HeatFlowRate | Q_flow_nom | 5e3*100 | Nominal heat flow rate at a given temperature difference |
| Real | n | 1.333 | Exponent for radiators |
| SI.SpecificHeatCapacity | cp | 4200 | Specific heat capacity |
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 |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| SI.MassFlowRate | m_flow | ||
| SI.Temperature | T_s | ||
| SI.Temperature | T_r | ||
| SI.SpecificEnthalpy | h |