modelnode

Information

1. Purpose of model

This model represents a district-heating node. It performs ideal mixing separately for the supply side and the return side. It applies a first-order dynamic on specific enthalpy and mass flows at the connection points to simulate transport delays.

It can be used to decouple subsystems in large district heating networks to improve numerical stability.

2. Level of detail, physical effects considered, and physical insight

Ideal mixing of mass fractions and enthalpy.

Mass conservation for supply and return.

First-order delay (tau_delay) for enthalpy and junction mass flows.

3. Limits of validity

No pipe storage, pressure losses, or heat losses considered.

4. Interfaces

n Supply and return ports, optional junction ports.

5. Nomenclature

(no remarks)

6. Governing Equations

Mass balance: Total inflows equal zero.

Equal pressure: All supply ports share the same pressure and all return ports share the same pressure

Ideal mixing (mass-flow-weighted).

First-order delay for enthalpy and mass flow.

7. Remarks for Usage

Model is simplified; combine with detailed network components.

8. Validation

(no remarks)

9. References

(no remarks)

10. Version History

Model created by Gas- und Wärme-Institut Essen and XRG, 2022

Modified by Stefanie Ruppert, 2025

Parameters

Connectors

Components